* [RFC][PATCH 0/8] Critical Page Pool
@ 2005-11-18 19:32 Matthew Dobson
2005-11-18 19:36 ` [RFC][PATCH 1/8] Create " Matthew Dobson
` (11 more replies)
0 siblings, 12 replies; 28+ messages in thread
From: Matthew Dobson @ 2005-11-18 19:32 UTC (permalink / raw)
To: linux-kernel; +Cc: Linux Memory Management
We have a clustering product that needs to be able to guarantee that the
networking system won't stop functioning in the case of OOM/low memory
condition. The current mempool system is inadequate because to keep the
whole networking stack functioning, we need more than 1 or 2 slab caches to
be guaranteed. We need to guarantee that any request made with a specific
flag will succeed, assuming of course that you've made your "critical page
pool" big enough.
The following patch series implements such a critical page pool. It
creates 2 userspace triggers:
/proc/sys/vm/critical_pages: write the number of pages you want to reserve
for the critical pool into this file
/proc/sys/vm/in_emergency: write a non-zero value to tell the kernel that
the system is in an emergency state and authorize the kernel to dip into
the critical pool to satisfy critical allocations.
We mark critical allocations with the __GFP_CRITICAL flag, and when the
system is in an emergency state, we are allowed to delve into this pool to
satisfy __GFP_CRITICAL allocations that cannot be satisfied through the
normal means.
Feedback on our approach would be appreciated.
Thanks!
-Matt
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^ permalink raw reply [flat|nested] 28+ messages in thread
* [RFC][PATCH 1/8] Create Critical Page Pool
2005-11-18 19:32 [RFC][PATCH 0/8] Critical Page Pool Matthew Dobson
@ 2005-11-18 19:36 ` Matthew Dobson
2005-11-19 0:08 ` Paul Jackson
2005-11-18 19:36 ` [RFC][PATCH 2/8] Create emergency trigger Matthew Dobson
` (10 subsequent siblings)
11 siblings, 1 reply; 28+ messages in thread
From: Matthew Dobson @ 2005-11-18 19:36 UTC (permalink / raw)
To: linux-kernel; +Cc: Linux Memory Management
[-- Attachment #1: Type: text/plain, Size: 77 bytes --]
Create the critical page pool and it's associated /proc/sys/vm/ file.
-Matt
[-- Attachment #2: critical_pool.patch --]
[-- Type: text/x-patch, Size: 10222 bytes --]
Implement a Critical Page Pool:
* Write a number of pages into /proc/sys/vm/critical_pages
* These pages will be reserved for 'critical' allocations, signified
by the __GFP_CRITICAL flag passed to an allocation request.
Signed-off-by: Matthew Dobson <colpatch@us.ibm.com>
Index: linux-2.6.15-rc1+critical_pool/Documentation/sysctl/vm.txt
===================================================================
--- linux-2.6.15-rc1+critical_pool.orig/Documentation/sysctl/vm.txt 2005-11-15 13:47:14.000000000 -0800
+++ linux-2.6.15-rc1+critical_pool/Documentation/sysctl/vm.txt 2005-11-17 16:27:33.108545112 -0800
@@ -26,6 +26,7 @@ Currently, these files are in /proc/sys/
- min_free_kbytes
- laptop_mode
- block_dump
+- critical_pages
==============================================================
@@ -102,3 +103,12 @@ This is used to force the Linux VM to ke
of kilobytes free. The VM uses this number to compute a pages_min
value for each lowmem zone in the system. Each lowmem zone gets
a number of reserved free pages based proportionally on its size.
+
+==============================================================
+
+critical_pages:
+
+This is used to force the Linux VM to reserve a pool of pages for
+emergency (__GFP_CRITICAL) allocations. Allocations with this flag
+MUST succeed.
+The number written into this file is the number of pages to reserve.
Index: linux-2.6.15-rc1+critical_pool/include/linux/gfp.h
===================================================================
--- linux-2.6.15-rc1+critical_pool.orig/include/linux/gfp.h 2005-11-15 13:46:37.000000000 -0800
+++ linux-2.6.15-rc1+critical_pool/include/linux/gfp.h 2005-11-17 16:28:28.375143312 -0800
@@ -41,6 +41,7 @@ struct vm_area_struct;
#define __GFP_NOMEMALLOC ((__force gfp_t)0x10000u) /* Don't use emergency reserves */
#define __GFP_NORECLAIM ((__force gfp_t)0x20000u) /* No realy zone reclaim during allocation */
#define __GFP_HARDWALL ((__force gfp_t)0x40000u) /* Enforce hardwall cpuset memory allocs */
+#define __GFP_CRITICAL ((__force gfp_t)0x80000u) /* Critical allocation. MUST succeed! */
#define __GFP_BITS_SHIFT 20 /* Room for 20 __GFP_FOO bits */
#define __GFP_BITS_MASK ((__force gfp_t)((1 << __GFP_BITS_SHIFT) - 1))
@@ -49,7 +50,8 @@ struct vm_area_struct;
#define GFP_LEVEL_MASK (__GFP_WAIT|__GFP_HIGH|__GFP_IO|__GFP_FS| \
__GFP_COLD|__GFP_NOWARN|__GFP_REPEAT| \
__GFP_NOFAIL|__GFP_NORETRY|__GFP_NO_GROW|__GFP_COMP| \
- __GFP_NOMEMALLOC|__GFP_NORECLAIM|__GFP_HARDWALL)
+ __GFP_NOMEMALLOC|__GFP_NORECLAIM|__GFP_HARDWALL| \
+ __GFP_CRITICAL)
#define GFP_ATOMIC (__GFP_HIGH)
#define GFP_NOIO (__GFP_WAIT)
@@ -58,6 +60,8 @@ struct vm_area_struct;
#define GFP_USER (__GFP_WAIT | __GFP_IO | __GFP_FS | __GFP_HARDWALL)
#define GFP_HIGHUSER (__GFP_WAIT | __GFP_IO | __GFP_FS | __GFP_HARDWALL | \
__GFP_HIGHMEM)
+#define GFP_ATOMIC_CRIT (GFP_ATOMIC | __GFP_CRITICAL)
+#define GFP_KERNEL_CRIT (GFP_KERNEL | __GFP_CRITICAL)
/* Flag - indicates that the buffer will be suitable for DMA. Ignored on some
platforms, used as appropriate on others */
Index: linux-2.6.15-rc1+critical_pool/include/linux/sysctl.h
===================================================================
--- linux-2.6.15-rc1+critical_pool.orig/include/linux/sysctl.h 2005-11-15 13:46:38.000000000 -0800
+++ linux-2.6.15-rc1+critical_pool/include/linux/sysctl.h 2005-11-17 16:27:33.111544656 -0800
@@ -181,6 +181,7 @@ enum
VM_VFS_CACHE_PRESSURE=26, /* dcache/icache reclaim pressure */
VM_LEGACY_VA_LAYOUT=27, /* legacy/compatibility virtual address space layout */
VM_SWAP_TOKEN_TIMEOUT=28, /* default time for token time out */
+ VM_CRITICAL_PAGES=30, /* # of pages to reserve for __GFP_CRITICAL allocs */
};
Index: linux-2.6.15-rc1+critical_pool/kernel/sysctl.c
===================================================================
--- linux-2.6.15-rc1+critical_pool.orig/kernel/sysctl.c 2005-11-15 13:47:25.000000000 -0800
+++ linux-2.6.15-rc1+critical_pool/kernel/sysctl.c 2005-11-17 16:27:33.116543896 -0800
@@ -849,6 +849,16 @@ static ctl_table vm_table[] = {
.strategy = &sysctl_jiffies,
},
#endif
+ {
+ .ctl_name = VM_CRITICAL_PAGES,
+ .procname = "critical_pages",
+ .data = &critical_pages,
+ .maxlen = sizeof(critical_pages),
+ .mode = 0644,
+ .proc_handler = &critical_pages_sysctl_handler,
+ .strategy = &sysctl_intvec,
+ .extra1 = &zero,
+ },
{ .ctl_name = 0 }
};
Index: linux-2.6.15-rc1+critical_pool/mm/page_alloc.c
===================================================================
--- linux-2.6.15-rc1+critical_pool.orig/mm/page_alloc.c 2005-11-15 13:47:26.000000000 -0800
+++ linux-2.6.15-rc1+critical_pool/mm/page_alloc.c 2005-11-17 16:27:33.120543288 -0800
@@ -53,6 +53,65 @@ unsigned long totalram_pages __read_most
unsigned long totalhigh_pages __read_mostly;
long nr_swap_pages;
+/* The number of pages to maintain in the critical page pool */
+int critical_pages = 0;
+
+/* Critical Page Pool control structure */
+static struct critical_pool {
+ unsigned int free;
+ spinlock_t lock;
+ struct list_head pages;
+} critical_pool = {
+ .free = 0,
+ .lock = SPIN_LOCK_UNLOCKED,
+ .pages = LIST_HEAD_INIT(critical_pool.pages),
+};
+
+/* MCD - This needs to be arch specific */
+#define CRITICAL_POOL_GFPMASK (GFP_KERNEL)
+
+static inline int is_critical_pool_full(void)
+{
+ return critical_pool.free >= critical_pages;
+}
+
+static inline struct page *get_critical_page(gfp_t gfpmask)
+{
+ struct page *page = NULL;
+
+ spin_lock(&critical_pool.lock);
+ if (!list_empty(&critical_pool.pages)) {
+ /* Grab the next free critical pool page */
+ page = list_entry(critical_pool.pages.next, struct page, lru);
+ list_del(&page->lru);
+ critical_pool.free--;
+ }
+ spin_unlock(&critical_pool.lock);
+
+ return page;
+}
+
+static inline int put_critical_page(struct page *page)
+{
+ int ret = 0;
+
+ spin_lock(&critical_pool.lock);
+ if (!is_critical_pool_full()) {
+ /*
+ * We snached this page away in the process of being freed, so
+ * we must re-increment it's count so we don't cause problems
+ * when we hand it back out to a future __GFP_CRITICAL alloc.
+ */
+ BUG_ON(!get_page_testone(page));
+ list_add(&page->lru, &critical_pool.pages);
+ critical_pool.free++;
+ ret = 1;
+ }
+ spin_unlock(&critical_pool.lock);
+
+ return ret;
+}
+
/*
* results with 256, 32 in the lowmem_reserve sysctl:
* 1G machine -> (16M dma, 800M-16M normal, 1G-800M high)
@@ -305,6 +364,10 @@ static inline void __free_pages_bulk (st
if (unlikely(order))
destroy_compound_page(page, order);
+ else if (!is_critical_pool_full())
+ /* If the critical pool isn't full, add this page to it */
+ if (put_critical_page(page))
+ return;
page_idx = page_to_pfn(page) & ((1 << MAX_ORDER) - 1);
@@ -984,6 +1047,20 @@ rebalance:
}
nopage:
+ /*
+ * This is the LAST DITCH effort. We maintain a pool of 'critical'
+ * pages specifically for allocation requests marked __GFP_CRITICAL.
+ * Rather than fail one of these allocations, take a page (if any)
+ * from the critical pool.
+ */
+ if (gfp_mask & __GFP_CRITICAL) {
+ page = get_critical_page(gfp_mask);
+ if (page) {
+ z = page_zone(page);
+ goto got_pg;
+ }
+ }
+
if (!(gfp_mask & __GFP_NOWARN) && printk_ratelimit()) {
printk(KERN_WARNING "%s: page allocation failure."
" order:%d, mode:0x%x\n",
@@ -2522,6 +2599,68 @@ int lowmem_reserve_ratio_sysctl_handler(
return 0;
}
+static inline void fill_critical_pool(int num)
+{
+ struct page *page;
+ int i;
+
+ for (i = 0; i < num; i++) {
+ page = alloc_page(CRITICAL_POOL_GFPMASK);
+ if (!page)
+ return;
+ spin_lock(&critical_pool.lock);
+ list_add(&page->lru, &critical_pool.pages);
+ critical_pool.free++;
+ spin_unlock(&critical_pool.lock);
+ }
+}
+
+static inline void drain_critical_pool(int num)
+{
+ struct page *page;
+ int i;
+
+ for (i = 0; i < num; i++) {
+ spin_lock(&critical_pool.lock);
+ BUG_ON(critical_pool.free < 0);
+ if (list_empty(&critical_pool.pages) || !critical_pool.free) {
+ spin_unlock(&critical_pool.lock);
+ break;
+ }
+
+ page = list_entry(critical_pool.pages.next, struct page, lru);
+ list_del(&page->lru);
+ critical_pool.free--;
+ spin_unlock(&critical_pool.lock);
+
+ __free_pages(page, 0);
+ }
+}
+
+/*
+ * critical_pages_sysctl_handler - handle writes to /proc/sys/vm/critical_pages
+ * Whenever this file changes, add/remove pages to/from the critical page
+ * pool.
+ */
+int critical_pages_sysctl_handler(ctl_table *table, int write,
+ struct file *file, void __user *buffer,
+ size_t *length, loff_t *ppos)
+{
+ int num;
+
+ proc_dointvec(table, write, file, buffer, length, ppos);
+ if (!write)
+ return 0;
+
+ num = critical_pages - critical_pool.free;
+ if (num > 0)
+ fill_critical_pool(num);
+ else if (num < 0)
+ drain_critical_pool(-num);
+
+ return 0;
+}
+
__initdata int hashdist = HASHDIST_DEFAULT;
#ifdef CONFIG_NUMA
Index: linux-2.6.15-rc1+critical_pool/include/linux/mmzone.h
===================================================================
--- linux-2.6.15-rc1+critical_pool.orig/include/linux/mmzone.h 2005-11-15 13:46:38.000000000 -0800
+++ linux-2.6.15-rc1+critical_pool/include/linux/mmzone.h 2005-11-17 16:27:33.121543136 -0800
@@ -430,6 +430,8 @@ int min_free_kbytes_sysctl_handler(struc
extern int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1];
int lowmem_reserve_ratio_sysctl_handler(struct ctl_table *, int, struct file *,
void __user *, size_t *, loff_t *);
+int critical_pages_sysctl_handler(struct ctl_table *, int, struct file *,
+ void __user *, size_t *, loff_t *);
#include <linux/topology.h>
/* Returns the number of the current Node. */
Index: linux-2.6.15-rc1+critical_pool/include/linux/mm.h
===================================================================
--- linux-2.6.15-rc1+critical_pool.orig/include/linux/mm.h 2005-11-15 13:46:36.000000000 -0800
+++ linux-2.6.15-rc1+critical_pool/include/linux/mm.h 2005-11-17 16:27:33.125542528 -0800
@@ -32,6 +32,8 @@ extern int sysctl_legacy_va_layout;
#define sysctl_legacy_va_layout 0
#endif
+extern int critical_pages;
+
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/processor.h>
^ permalink raw reply [flat|nested] 28+ messages in thread
* [RFC][PATCH 2/8] Create emergency trigger
2005-11-18 19:32 [RFC][PATCH 0/8] Critical Page Pool Matthew Dobson
2005-11-18 19:36 ` [RFC][PATCH 1/8] Create " Matthew Dobson
@ 2005-11-18 19:36 ` Matthew Dobson
2005-11-19 0:21 ` Paul Jackson
2005-11-18 19:40 ` [RFC][PATCH 3/8] Slab cleanup Matthew Dobson
` (9 subsequent siblings)
11 siblings, 1 reply; 28+ messages in thread
From: Matthew Dobson @ 2005-11-18 19:36 UTC (permalink / raw)
To: linux-kernel; +Cc: Linux Memory Management
[-- Attachment #1: Type: text/plain, Size: 40 bytes --]
Create the in_emergency trigger.
-Matt
[-- Attachment #2: emergency_trigger.patch --]
[-- Type: text/x-patch, Size: 4892 bytes --]
Create a userspace trigger: /proc/sys/vm/in_emergency that notifies the kernel
that the system is in an emergency state, and allows the kernel to delve into
the 'critical pool' to satisfy __GFP_CRITICAL allocations.
Signed-off-by: Matthew Dobson <colpatch@us.ibm.com>
Index: linux-2.6.15-rc1+critical_pool/Documentation/sysctl/vm.txt
===================================================================
--- linux-2.6.15-rc1+critical_pool.orig/Documentation/sysctl/vm.txt 2005-11-17 16:51:19.000000000 -0800
+++ linux-2.6.15-rc1+critical_pool/Documentation/sysctl/vm.txt 2005-11-17 16:51:20.000000000 -0800
@@ -27,6 +27,7 @@ Currently, these files are in /proc/sys/
- laptop_mode
- block_dump
- critical_pages
+- in_emergency
==============================================================
@@ -112,3 +113,12 @@ This is used to force the Linux VM to re
emergency (__GFP_CRITICAL) allocations. Allocations with this flag
MUST succeed.
The number written into this file is the number of pages to reserve.
+
+==============================================================
+
+in_emergency:
+
+This is used to let the Linux VM know that userspace thinks that the system is
+in an emergency situation.
+Writing a non-zero value into this file tells the VM we *are* in an emergency
+situation & writing zero tells the VM we *are not* in an emergency situation.
Index: linux-2.6.15-rc1+critical_pool/include/linux/sysctl.h
===================================================================
--- linux-2.6.15-rc1+critical_pool.orig/include/linux/sysctl.h 2005-11-17 16:51:19.000000000 -0800
+++ linux-2.6.15-rc1+critical_pool/include/linux/sysctl.h 2005-11-17 16:51:20.000000000 -0800
@@ -182,6 +182,7 @@ enum
VM_LEGACY_VA_LAYOUT=27, /* legacy/compatibility virtual address space layout */
VM_SWAP_TOKEN_TIMEOUT=28, /* default time for token time out */
VM_CRITICAL_PAGES=30, /* # of pages to reserve for __GFP_CRITICAL allocs */
+ VM_IN_EMERGENCY=31, /* tell the VM if we are/aren't in an emergency */
};
Index: linux-2.6.15-rc1+critical_pool/kernel/sysctl.c
===================================================================
--- linux-2.6.15-rc1+critical_pool.orig/kernel/sysctl.c 2005-11-17 16:51:19.000000000 -0800
+++ linux-2.6.15-rc1+critical_pool/kernel/sysctl.c 2005-11-17 16:51:20.000000000 -0800
@@ -859,6 +859,16 @@ static ctl_table vm_table[] = {
.strategy = &sysctl_intvec,
.extra1 = &zero,
},
+ {
+ .ctl_name = VM_IN_EMERGENCY,
+ .procname = "in_emergency",
+ .data = &system_in_emergency,
+ .maxlen = sizeof(system_in_emergency),
+ .mode = 0644,
+ .proc_handler = &proc_dointvec,
+ .strategy = &sysctl_intvec,
+ .extra1 = &zero,
+ },
{ .ctl_name = 0 }
};
Index: linux-2.6.15-rc1+critical_pool/mm/page_alloc.c
===================================================================
--- linux-2.6.15-rc1+critical_pool.orig/mm/page_alloc.c 2005-11-17 16:51:19.000000000 -0800
+++ linux-2.6.15-rc1+critical_pool/mm/page_alloc.c 2005-11-18 11:24:02.024254248 -0800
@@ -53,6 +53,9 @@ unsigned long totalram_pages __read_most
unsigned long totalhigh_pages __read_mostly;
long nr_swap_pages;
+/* Is the sytem in an emergency situation? */
+int system_in_emergency = 0;
+
/* The number of pages to maintain in the critical page pool */
int critical_pages = 0;
@@ -865,7 +868,7 @@ struct page * fastcall
__alloc_pages(gfp_t gfp_mask, unsigned int order,
struct zonelist *zonelist)
{
- const gfp_t wait = gfp_mask & __GFP_WAIT;
+ gfp_t wait = gfp_mask & __GFP_WAIT;
struct zone **zones, *z;
struct page *page;
struct reclaim_state reclaim_state;
@@ -876,6 +879,16 @@ __alloc_pages(gfp_t gfp_mask, unsigned i
int can_try_harder;
int did_some_progress;
+ if (is_emergency_alloc(gfp_mask)) {
+ /*
+ * If the system is 'in emergency' and this is a critical
+ * allocation, then make sure we don't sleep
+ */
+ gfp_mask &= ~__GFP_WAIT;
+ gfp_mask |= __GFP_NORECLAIM | __GFP_HIGH;
+ wait = 0;
+ }
+
might_sleep_if(wait);
/*
@@ -1053,7 +1066,7 @@ nopage:
* Rather than fail one of these allocations, take a page (if any)
* from the critical pool.
*/
- if (gfp_mask & __GFP_CRITICAL) {
+ if (is_emergency_alloc(gfp_mask)) {
page = get_critical_page(gfp_mask);
if (page) {
z = page_zone(page);
Index: linux-2.6.15-rc1+critical_pool/include/linux/mm.h
===================================================================
--- linux-2.6.15-rc1+critical_pool.orig/include/linux/mm.h 2005-11-17 16:51:19.000000000 -0800
+++ linux-2.6.15-rc1+critical_pool/include/linux/mm.h 2005-11-17 16:51:20.000000000 -0800
@@ -33,6 +33,12 @@ extern int sysctl_legacy_va_layout;
#endif
extern int critical_pages;
+extern int system_in_emergency;
+
+static inline int is_emergency_alloc(gfp_t gfpmask)
+{
+ return system_in_emergency && (gfpmask & __GFP_CRITICAL);
+}
#include <asm/page.h>
#include <asm/pgtable.h>
^ permalink raw reply [flat|nested] 28+ messages in thread
* [RFC][PATCH 3/8] Slab cleanup
2005-11-18 19:32 [RFC][PATCH 0/8] Critical Page Pool Matthew Dobson
2005-11-18 19:36 ` [RFC][PATCH 1/8] Create " Matthew Dobson
2005-11-18 19:36 ` [RFC][PATCH 2/8] Create emergency trigger Matthew Dobson
@ 2005-11-18 19:40 ` Matthew Dobson
2005-11-18 19:41 ` [RFC][PATCH 4/8] Fix a bug in scsi_get_command Matthew Dobson
` (8 subsequent siblings)
11 siblings, 0 replies; 28+ messages in thread
From: Matthew Dobson @ 2005-11-18 19:40 UTC (permalink / raw)
To: linux-kernel; +Cc: Linux Memory Management
[-- Attachment #1: Type: text/plain, Size: 301 bytes --]
This patch isn't strictly necessary for the series, but the patch to add
critical pool support to the slab allocator is based on top of these
cleanups. If any/all of the cleanup work is rejected (discussed in a
seperate, earlier thread), then I will rebase the following patches as
necessary.
-Matt
[-- Attachment #2: slab_cleanup.patch --]
[-- Type: text/x-patch, Size: 101031 bytes --]
Index: linux-2.6.15-rc1+slab_cleanup/include/linux/percpu.h
===================================================================
--- linux-2.6.15-rc1+slab_cleanup.orig/include/linux/percpu.h 2005-11-15 15:21:47.659921992 -0800
+++ linux-2.6.15-rc1+slab_cleanup/include/linux/percpu.h 2005-11-15 15:23:47.699673176 -0800
@@ -33,14 +33,14 @@ struct percpu_data {
(__typeof__(ptr))__p->ptrs[(cpu)]; \
})
-extern void *__alloc_percpu(size_t size, size_t align);
+extern void *__alloc_percpu(size_t size);
extern void free_percpu(const void *);
#else /* CONFIG_SMP */
#define per_cpu_ptr(ptr, cpu) (ptr)
-static inline void *__alloc_percpu(size_t size, size_t align)
+static inline void *__alloc_percpu(size_t size)
{
void *ret = kmalloc(size, GFP_KERNEL);
if (ret)
@@ -55,7 +55,6 @@ static inline void free_percpu(const voi
#endif /* CONFIG_SMP */
/* Simple wrapper for the common case: zeros memory. */
-#define alloc_percpu(type) \
- ((type *)(__alloc_percpu(sizeof(type), __alignof__(type))))
+#define alloc_percpu(type) ((type *)(__alloc_percpu(sizeof(type))))
#endif /* __LINUX_PERCPU_H */
Index: linux-2.6.15-rc1+slab_cleanup/mm/slab.c
===================================================================
--- linux-2.6.15-rc1+slab_cleanup.orig/mm/slab.c 2005-11-15 14:42:52.871863728 -0800
+++ linux-2.6.15-rc1+slab_cleanup/mm/slab.c 2005-11-15 15:23:52.131999360 -0800
@@ -50,7 +50,7 @@
* The head array is strictly LIFO and should improve the cache hit rates.
* On SMP, it additionally reduces the spinlock operations.
*
- * The c_cpuarray may not be read with enabled local interrupts -
+ * The c_cpuarray may not be read with enabled local interrupts -
* it's changed with a smp_call_function().
*
* SMP synchronization:
@@ -73,7 +73,7 @@
* can never happen inside an interrupt (kmem_cache_create(),
* kmem_cache_shrink() and kmem_cache_reap()).
*
- * At present, each engine can be growing a cache. This should be blocked.
+ * At present each engine can be growing a cache. This should be blocked.
*
* 15 March 2005. NUMA slab allocator.
* Shai Fultheim <shai@scalex86.org>.
@@ -86,53 +86,52 @@
* All object allocations for a node occur from node specific slab lists.
*/
-#include <linux/config.h>
-#include <linux/slab.h>
-#include <linux/mm.h>
-#include <linux/swap.h>
-#include <linux/cache.h>
-#include <linux/interrupt.h>
-#include <linux/init.h>
-#include <linux/compiler.h>
-#include <linux/seq_file.h>
-#include <linux/notifier.h>
-#include <linux/kallsyms.h>
-#include <linux/cpu.h>
-#include <linux/sysctl.h>
-#include <linux/module.h>
-#include <linux/rcupdate.h>
-#include <linux/string.h>
-#include <linux/nodemask.h>
-
-#include <asm/uaccess.h>
-#include <asm/cacheflush.h>
-#include <asm/tlbflush.h>
-#include <asm/page.h>
+#include <linux/config.h>
+#include <linux/slab.h>
+#include <linux/mm.h>
+#include <linux/swap.h>
+#include <linux/cache.h>
+#include <linux/interrupt.h>
+#include <linux/init.h>
+#include <linux/compiler.h>
+#include <linux/seq_file.h>
+#include <linux/notifier.h>
+#include <linux/kallsyms.h>
+#include <linux/cpu.h>
+#include <linux/sysctl.h>
+#include <linux/module.h>
+#include <linux/rcupdate.h>
+#include <linux/string.h>
+#include <linux/nodemask.h>
+
+#include <asm/uaccess.h>
+#include <asm/cacheflush.h>
+#include <asm/tlbflush.h>
+#include <asm/page.h>
/*
* DEBUG - 1 for kmem_cache_create() to honour; SLAB_DEBUG_INITIAL,
* SLAB_RED_ZONE & SLAB_POISON.
- * 0 for faster, smaller code (especially in the critical paths).
+ * 0 for faster, smaller code (especially in the critical paths)
*
* STATS - 1 to collect stats for /proc/slabinfo.
- * 0 for faster, smaller code (especially in the critical paths).
+ * 0 for faster, smaller code (especially in the critical paths)
*
* FORCED_DEBUG - 1 enables SLAB_RED_ZONE and SLAB_POISON (if possible)
*/
-
#ifdef CONFIG_DEBUG_SLAB
-#define DEBUG 1
-#define STATS 1
-#define FORCED_DEBUG 1
+#define DEBUG 1
+#define STATS 1
+#define FORCED_DEBUG 1
#else
-#define DEBUG 0
-#define STATS 0
-#define FORCED_DEBUG 0
+#define DEBUG 0
+#define STATS 0
+#define FORCED_DEBUG 0
#endif
/* Shouldn't this be in a header file somewhere? */
-#define BYTES_PER_WORD sizeof(void *)
+#define BYTES_PER_WORD sizeof(void *)
#ifndef cache_line_size
#define cache_line_size() L1_CACHE_BYTES
@@ -180,7 +179,7 @@
SLAB_DESTROY_BY_RCU)
#endif
-/*
+/**
* kmem_bufctl_t:
*
* Bufctl's are used for linking objs within a slab
@@ -198,13 +197,13 @@
* Note: This limit can be raised by introducing a general cache whose size
* is less than 512 (PAGE_SIZE<<3), but greater than 256.
*/
-
typedef unsigned int kmem_bufctl_t;
#define BUFCTL_END (((kmem_bufctl_t)(~0U))-0)
#define BUFCTL_FREE (((kmem_bufctl_t)(~0U))-1)
-#define SLAB_LIMIT (((kmem_bufctl_t)(~0U))-2)
+#define SLAB_LIMIT (((kmem_bufctl_t)(~0U))-2)
-/* Max number of objs-per-slab for caches which use off-slab slabs.
+/*
+ * Max number of objs-per-slab for caches which use off-slab slabs.
* Needed to avoid a possible looping condition in cache_grow().
*/
static unsigned long offslab_limit;
@@ -220,9 +219,9 @@ struct slab {
struct list_head list;
unsigned long colouroff;
void *s_mem; /* including colour offset */
- unsigned int inuse; /* num of objs active in slab */
+ unsigned int inuse; /* # of objs active in slab */
kmem_bufctl_t free;
- unsigned short nodeid;
+ unsigned short nid; /* node number slab is on */
};
/*
@@ -264,36 +263,38 @@ struct array_cache {
unsigned int limit;
unsigned int batchcount;
unsigned int touched;
- spinlock_t lock;
- void *entry[0]; /*
- * Must have this definition in here for the proper
- * alignment of array_cache. Also simplifies accessing
- * the entries.
- * [0] is for gcc 2.95. It should really be [].
- */
+ spinlock_t lock;
+ /*
+ * Must have this definition in here for the proper alignment of
+ * array_cache. Also simplifies accessing the entries.
+ * [0] is for gcc 2.95. It should really be [].
+ */
+ void *entry[0];
};
-/* bootstrap: The caches do not work without cpuarrays anymore,
+/*
+ * bootstrap: The caches do not work without cpuarrays anymore,
* but the cpuarrays are allocated from the generic caches...
*/
#define BOOT_CPUCACHE_ENTRIES 1
struct arraycache_init {
struct array_cache cache;
- void * entries[BOOT_CPUCACHE_ENTRIES];
+ void *entries[BOOT_CPUCACHE_ENTRIES];
};
/*
* The slab lists for all objects.
*/
struct kmem_list3 {
- struct list_head slabs_partial; /* partial list first, better asm code */
+ /* place the partial list first for better assembly code */
+ struct list_head slabs_partial;
struct list_head slabs_full;
struct list_head slabs_free;
- unsigned long free_objects;
- unsigned long next_reap;
- int free_touched;
- unsigned int free_limit;
- spinlock_t list_lock;
+ unsigned long free_objects;
+ unsigned long next_reap;
+ int free_touched;
+ unsigned int free_limit;
+ spinlock_t list_lock;
struct array_cache *shared; /* shared per node */
struct array_cache **alien; /* on other nodes */
};
@@ -301,11 +302,11 @@ struct kmem_list3 {
/*
* Need this for bootstrapping a per node allocator.
*/
-#define NUM_INIT_LISTS (2 * MAX_NUMNODES + 1)
+#define NUM_INIT_LISTS (2 * MAX_NUMNODES + 1)
struct kmem_list3 __initdata initkmem_list3[NUM_INIT_LISTS];
-#define CACHE_CACHE 0
-#define SIZE_AC 1
-#define SIZE_L3 (1 + MAX_NUMNODES)
+#define CACHE_CACHE 0
+#define SIZE_AC 1
+#define SIZE_L3 (1 + MAX_NUMNODES)
/*
* This function must be completely optimized away if
@@ -318,10 +319,10 @@ static __always_inline int index_of(cons
if (__builtin_constant_p(size)) {
int i = 0;
-#define CACHE(x) \
- if (size <=x) \
- return i; \
- else \
+#define CACHE(x) \
+ if (size <= x) \
+ return i; \
+ else \
i++;
#include "linux/kmalloc_sizes.h"
#undef CACHE
@@ -349,17 +350,17 @@ static inline void kmem_list3_init(struc
parent->free_touched = 0;
}
-#define MAKE_LIST(cachep, listp, slab, nodeid) \
- do { \
- INIT_LIST_HEAD(listp); \
- list_splice(&(cachep->nodelists[nodeid]->slab), listp); \
+#define MAKE_LIST(cachep, listp, slab, nid) \
+ do { \
+ INIT_LIST_HEAD(listp); \
+ list_splice(&(cachep->nodelists[nid]->slab), listp); \
} while (0)
-#define MAKE_ALL_LISTS(cachep, ptr, nodeid) \
- do { \
- MAKE_LIST((cachep), (&(ptr)->slabs_full), slabs_full, nodeid); \
- MAKE_LIST((cachep), (&(ptr)->slabs_partial), slabs_partial, nodeid); \
- MAKE_LIST((cachep), (&(ptr)->slabs_free), slabs_free, nodeid); \
+#define MAKE_ALL_LISTS(cachep, ptr, nid) \
+ do { \
+ MAKE_LIST((cachep), &(ptr)->slabs_full, slabs_full, nid); \
+ MAKE_LIST((cachep), &(ptr)->slabs_partial, slabs_partial, nid);\
+ MAKE_LIST((cachep), &(ptr)->slabs_free, slabs_free, nid); \
} while (0)
/*
@@ -367,7 +368,6 @@ static inline void kmem_list3_init(struc
*
* manages a cache.
*/
-
struct kmem_cache {
/* 1) per-cpu data, touched during every alloc/free */
struct array_cache *array[NR_CPUS];
@@ -428,10 +428,11 @@ struct kmem_cache {
};
#define CFLGS_OFF_SLAB (0x80000000UL)
-#define OFF_SLAB(x) ((x)->flags & CFLGS_OFF_SLAB)
+#define OFF_SLAB(x) ((x)->flags & CFLGS_OFF_SLAB)
#define BATCHREFILL_LIMIT 16
-/* Optimization question: fewer reaps means less
+/*
+ * Optimization question: fewer reaps means less
* probability for unnessary cpucache drain/refill cycles.
*
* OTOH the cpuarrays can contain lots of objects,
@@ -441,20 +442,19 @@ struct kmem_cache {
#define REAPTIMEOUT_LIST3 (4*HZ)
#if STATS
-#define STATS_INC_ACTIVE(x) ((x)->num_active++)
-#define STATS_DEC_ACTIVE(x) ((x)->num_active--)
-#define STATS_INC_ALLOCED(x) ((x)->num_allocations++)
-#define STATS_INC_GROWN(x) ((x)->grown++)
-#define STATS_INC_REAPED(x) ((x)->reaped++)
-#define STATS_SET_HIGH(x) do { if ((x)->num_active > (x)->high_mark) \
- (x)->high_mark = (x)->num_active; \
+#define STATS_INC_ACTIVE(x) ((x)->num_active++)
+#define STATS_DEC_ACTIVE(x) ((x)->num_active--)
+#define STATS_INC_ALLOCED(x) ((x)->num_allocations++)
+#define STATS_INC_GROWN(x) ((x)->grown++)
+#define STATS_INC_REAPED(x) ((x)->reaped++)
+#define STATS_SET_HIGH(x) do { if ((x)->num_active > (x)->high_mark) \
+ (x)->high_mark = (x)->num_active; \
} while (0)
-#define STATS_INC_ERR(x) ((x)->errors++)
-#define STATS_INC_NODEALLOCS(x) ((x)->node_allocs++)
-#define STATS_INC_NODEFREES(x) ((x)->node_frees++)
-#define STATS_SET_FREEABLE(x, i) \
- do { if ((x)->max_freeable < i) \
- (x)->max_freeable = i; \
+#define STATS_INC_ERR(x) ((x)->errors++)
+#define STATS_INC_NODEALLOCS(x) ((x)->node_allocs++)
+#define STATS_INC_NODEFREES(x) ((x)->node_frees++)
+#define STATS_SET_FREEABLE(x,i) do { if ((x)->max_freeable < i) \
+ (x)->max_freeable = i; \
} while (0)
#define STATS_INC_ALLOCHIT(x) atomic_inc(&(x)->allochit)
@@ -462,18 +462,16 @@ struct kmem_cache {
#define STATS_INC_FREEHIT(x) atomic_inc(&(x)->freehit)
#define STATS_INC_FREEMISS(x) atomic_inc(&(x)->freemiss)
#else
-#define STATS_INC_ACTIVE(x) do { } while (0)
-#define STATS_DEC_ACTIVE(x) do { } while (0)
-#define STATS_INC_ALLOCED(x) do { } while (0)
-#define STATS_INC_GROWN(x) do { } while (0)
-#define STATS_INC_REAPED(x) do { } while (0)
-#define STATS_SET_HIGH(x) do { } while (0)
-#define STATS_INC_ERR(x) do { } while (0)
-#define STATS_INC_NODEALLOCS(x) do { } while (0)
-#define STATS_INC_NODEFREES(x) do { } while (0)
-#define STATS_SET_FREEABLE(x, i) \
- do { } while (0)
-
+#define STATS_INC_ACTIVE(x) do { } while (0)
+#define STATS_DEC_ACTIVE(x) do { } while (0)
+#define STATS_INC_ALLOCED(x) do { } while (0)
+#define STATS_INC_GROWN(x) do { } while (0)
+#define STATS_INC_REAPED(x) do { } while (0)
+#define STATS_SET_HIGH(x) do { } while (0)
+#define STATS_INC_ERR(x) do { } while (0)
+#define STATS_INC_NODEALLOCS(x) do { } while (0)
+#define STATS_INC_NODEFREES(x) do { } while (0)
+#define STATS_SET_FREEABLE(x,i) do { } while (0)
#define STATS_INC_ALLOCHIT(x) do { } while (0)
#define STATS_INC_ALLOCMISS(x) do { } while (0)
#define STATS_INC_FREEHIT(x) do { } while (0)
@@ -481,27 +479,31 @@ struct kmem_cache {
#endif
#if DEBUG
-/* Magic nums for obj red zoning.
+/*
+ * Magic nums for obj red zoning.
* Placed in the first word before and the first word after an obj.
*/
-#define RED_INACTIVE 0x5A2CF071UL /* when obj is inactive */
-#define RED_ACTIVE 0x170FC2A5UL /* when obj is active */
+#define RED_INACTIVE 0x5A2CF071UL /* when obj is inactive */
+#define RED_ACTIVE 0x170FC2A5UL /* when obj is active */
/* ...and for poisoning */
-#define POISON_INUSE 0x5a /* for use-uninitialised poisoning */
+#define POISON_INUSE 0x5a /* for use-uninitialised poisoning */
#define POISON_FREE 0x6b /* for use-after-free poisoning */
-#define POISON_END 0xa5 /* end-byte of poisoning */
+#define POISON_END 0xa5 /* end-byte of poisoning */
-/* memory layout of objects:
+/* Don't use red zoning for ojects greater than this size */
+#define RED_ZONE_LIMIT 4096
+
+/*
+ * memory layout of objects:
* 0 : objp
- * 0 .. cachep->dbghead - BYTES_PER_WORD - 1: padding. This ensures that
+ * 0 .. cachep->dbghead - BYTES_PER_WORD-1: padding. This ensures that
* the end of an object is aligned with the end of the real
* allocation. Catches writes behind the end of the allocation.
- * cachep->dbghead - BYTES_PER_WORD .. cachep->dbghead - 1:
- * redzone word.
+ * cachep->dbghead - BYTES_PER_WORD .. cachep->dbghead - 1: redzone word.
* cachep->dbghead: The real object.
- * cachep->objsize - 2* BYTES_PER_WORD: redzone word [BYTES_PER_WORD long]
- * cachep->objsize - 1* BYTES_PER_WORD: last caller address [BYTES_PER_WORD long]
+ * cachep->objsize - 2*BYTES_PER_WORD: redzone word [BYTES_PER_WORD long]
+ * cachep->objsize - 1*BYTES_PER_WORD: last caller addr [BYTES_PER_WORD long]
*/
static int obj_dbghead(kmem_cache_t *cachep)
{
@@ -516,24 +518,24 @@ static int obj_reallen(kmem_cache_t *cac
static unsigned long *dbg_redzone1(kmem_cache_t *cachep, void *objp)
{
BUG_ON(!(cachep->flags & SLAB_RED_ZONE));
- return (unsigned long*) (objp+obj_dbghead(cachep)-BYTES_PER_WORD);
+ return (unsigned long *) (objp + obj_dbghead(cachep) - BYTES_PER_WORD);
}
static unsigned long *dbg_redzone2(kmem_cache_t *cachep, void *objp)
{
BUG_ON(!(cachep->flags & SLAB_RED_ZONE));
if (cachep->flags & SLAB_STORE_USER)
- return (unsigned long*) (objp+cachep->objsize-2*BYTES_PER_WORD);
- return (unsigned long*) (objp+cachep->objsize-BYTES_PER_WORD);
+ return (objp + cachep->objsize - 2 * BYTES_PER_WORD);
+ return (objp + cachep->objsize - BYTES_PER_WORD);
}
static void **dbg_userword(kmem_cache_t *cachep, void *objp)
{
BUG_ON(!(cachep->flags & SLAB_STORE_USER));
- return (void**)(objp+cachep->objsize-BYTES_PER_WORD);
+ return (void **)(objp + cachep->objsize - BYTES_PER_WORD);
}
-#else
+#else /* !DEBUG */
#define obj_dbghead(x) 0
#define obj_reallen(cachep) (cachep->objsize)
@@ -541,40 +543,41 @@ static void **dbg_userword(kmem_cache_t
#define dbg_redzone2(cachep, objp) ({BUG(); (unsigned long *)NULL;})
#define dbg_userword(cachep, objp) ({BUG(); (void **)NULL;})
-#endif
+#endif /* DEBUG */
/*
* Maximum size of an obj (in 2^order pages)
* and absolute limit for the gfp order.
*/
#if defined(CONFIG_LARGE_ALLOCS)
-#define MAX_OBJ_ORDER 13 /* up to 32Mb */
-#define MAX_GFP_ORDER 13 /* up to 32Mb */
+#define MAX_OBJ_ORDER 13 /* up to 32Mb */
+#define MAX_GFP_ORDER 13 /* up to 32Mb */
#elif defined(CONFIG_MMU)
-#define MAX_OBJ_ORDER 5 /* 32 pages */
-#define MAX_GFP_ORDER 5 /* 32 pages */
+#define MAX_OBJ_ORDER 5 /* 32 pages */
+#define MAX_GFP_ORDER 5 /* 32 pages */
#else
-#define MAX_OBJ_ORDER 8 /* up to 1Mb */
-#define MAX_GFP_ORDER 8 /* up to 1Mb */
+#define MAX_OBJ_ORDER 8 /* up to 1Mb */
+#define MAX_GFP_ORDER 8 /* up to 1Mb */
#endif
/*
* Do not go above this order unless 0 objects fit into the slab.
*/
-#define BREAK_GFP_ORDER_HI 1
-#define BREAK_GFP_ORDER_LO 0
+#define BREAK_GFP_ORDER_HI 1
+#define BREAK_GFP_ORDER_LO 0
static int slab_break_gfp_order = BREAK_GFP_ORDER_LO;
-/* Macros for storing/retrieving the cachep and or slab from the
+/*
+ * Macros for storing/retrieving the cachep and or slab from the
* global 'mem_map'. These are used to find the slab an obj belongs to.
* With kfree(), these are used to find the cache which an obj belongs to.
*/
-#define SET_PAGE_CACHE(pg,x) ((pg)->lru.next = (struct list_head *)(x))
-#define GET_PAGE_CACHE(pg) ((kmem_cache_t *)(pg)->lru.next)
-#define SET_PAGE_SLAB(pg,x) ((pg)->lru.prev = (struct list_head *)(x))
-#define GET_PAGE_SLAB(pg) ((struct slab *)(pg)->lru.prev)
+#define SET_PAGE_CACHE(pg,x) ((pg)->lru.next = (struct list_head *)(x))
+#define GET_PAGE_CACHE(pg) ((kmem_cache_t *)(pg)->lru.next)
+#define SET_PAGE_SLAB(pg,x) ((pg)->lru.prev = (struct list_head *)(x))
+#define GET_PAGE_SLAB(pg) ((struct slab *)(pg)->lru.prev)
-/* These are the default caches for kmalloc. Custom caches can have other sizes. */
+/* These are the default kmalloc caches. Custom caches can have other sizes. */
struct cache_sizes malloc_sizes[] = {
#define CACHE(x) { .cs_size = (x) },
#include <linux/kmalloc_sizes.h>
@@ -616,7 +619,7 @@ static kmem_cache_t cache_cache = {
};
/* Guard access to the cache-chain. */
-static struct semaphore cache_chain_sem;
+static struct semaphore cache_chain_sem;
static struct list_head cache_chain;
/*
@@ -640,10 +643,10 @@ static enum {
static DEFINE_PER_CPU(struct work_struct, reap_work);
-static void free_block(kmem_cache_t* cachep, void** objpp, int len, int node);
+static void free_block(kmem_cache_t *cachep, void **objpp, int len, int nid);
static void enable_cpucache (kmem_cache_t *cachep);
static void cache_reap (void *unused);
-static int __node_shrink(kmem_cache_t *cachep, int node);
+static int __node_shrink(kmem_cache_t *cachep, int nid);
static inline struct array_cache *ac_data(kmem_cache_t *cachep)
{
@@ -655,19 +658,19 @@ static inline kmem_cache_t *__find_gener
struct cache_sizes *csizep = malloc_sizes;
#if DEBUG
- /* This happens if someone tries to call
- * kmem_cache_create(), or __kmalloc(), before
- * the generic caches are initialized.
- */
+ /*
+ * This happens if someone calls kmem_cache_create() or __kmalloc()
+ * before the generic caches are initialized
+ */
BUG_ON(malloc_sizes[INDEX_AC].cs_cachep == NULL);
#endif
while (size > csizep->cs_size)
csizep++;
/*
- * Really subtle: The last entry with cs->cs_size==ULONG_MAX
- * has cs_{dma,}cachep==NULL. Thus no special case
- * for large kmalloc calls required.
+ * Really subtle: The last entry with cs->cs_size == ULONG_MAX has
+ * cs_{dma,}cachep == NULL, thus no special case for large kmalloc
+ * calls is required.
*/
if (unlikely(gfpflags & GFP_DMA))
return csizep->cs_dmacachep;
@@ -680,12 +683,12 @@ kmem_cache_t *kmem_find_general_cachep(s
}
EXPORT_SYMBOL(kmem_find_general_cachep);
-/* Cal the num objs, wastage, and bytes left over for a given slab size. */
+/* Calculate the num objs, wastage, & bytes left over for a given slab size. */
static void cache_estimate(unsigned long gfporder, size_t size, size_t align,
- int flags, size_t *left_over, unsigned int *num)
+ int flags, size_t *left_over, unsigned int *num)
{
int i;
- size_t wastage = PAGE_SIZE<<gfporder;
+ size_t wastage = PAGE_SIZE << gfporder;
size_t extra = 0;
size_t base = 0;
@@ -694,7 +697,7 @@ static void cache_estimate(unsigned long
extra = sizeof(kmem_bufctl_t);
}
i = 0;
- while (i*size + ALIGN(base+i*extra, align) <= wastage)
+ while (i * size + ALIGN(base + i * extra, align) <= wastage)
i++;
if (i > 0)
i--;
@@ -703,8 +706,8 @@ static void cache_estimate(unsigned long
i = SLAB_LIMIT;
*num = i;
- wastage -= i*size;
- wastage -= ALIGN(base+i*extra, align);
+ wastage -= i * size;
+ wastage -= ALIGN(base + i * extra, align);
*left_over = wastage;
}
@@ -718,7 +721,7 @@ static void __slab_error(const char *fun
}
/*
- * Initiate the reap timer running on the target CPU. We run at around 1 to 2Hz
+ * Initiate the reap timer running on the target CPU. We run at around 1-2Hz
* via the workqueue/eventd.
* Add the CPU number into the expiration time to minimize the possibility of
* the CPUs getting into lockstep and contending for the global cache chain
@@ -739,13 +742,13 @@ static void __devinit start_cpu_timer(in
}
}
-static struct array_cache *alloc_arraycache(int node, int entries,
- int batchcount)
+static struct array_cache *alloc_arraycache(int nid, int entries,
+ int batchcount)
{
- int memsize = sizeof(void*)*entries+sizeof(struct array_cache);
+ int memsize = sizeof(void *) * entries + sizeof(struct array_cache);
struct array_cache *nc = NULL;
- nc = kmalloc_node(memsize, GFP_KERNEL, node);
+ nc = kmalloc_node(memsize, GFP_KERNEL, nid);
if (nc) {
nc->avail = 0;
nc->limit = entries;
@@ -757,24 +760,24 @@ static struct array_cache *alloc_arrayca
}
#ifdef CONFIG_NUMA
-static inline struct array_cache **alloc_alien_cache(int node, int limit)
+static inline struct array_cache **alloc_alien_cache(int nid, int limit)
{
struct array_cache **ac_ptr;
- int memsize = sizeof(void*)*MAX_NUMNODES;
+ int memsize = sizeof(void *) * MAX_NUMNODES;
int i;
if (limit > 1)
limit = 12;
- ac_ptr = kmalloc_node(memsize, GFP_KERNEL, node);
+ ac_ptr = kmalloc_node(memsize, GFP_KERNEL, nid);
if (ac_ptr) {
for_each_node(i) {
- if (i == node || !node_online(i)) {
+ if (i == nid || !node_online(i)) {
ac_ptr[i] = NULL;
continue;
}
- ac_ptr[i] = alloc_arraycache(node, limit, 0xbaadf00d);
+ ac_ptr[i] = alloc_arraycache(nid, limit, 0xbaadf00d);
if (!ac_ptr[i]) {
- for (i--; i <=0; i--)
+ for (i--; i <= 0; i--)
kfree(ac_ptr[i]);
kfree(ac_ptr);
return NULL;
@@ -797,13 +800,14 @@ static inline void free_alien_cache(stru
kfree(ac_ptr);
}
-static inline void __drain_alien_cache(kmem_cache_t *cachep, struct array_cache *ac, int node)
+static inline void __drain_alien_cache(kmem_cache_t *cachep,
+ struct array_cache *ac, int nid)
{
- struct kmem_list3 *rl3 = cachep->nodelists[node];
+ struct kmem_list3 *rl3 = cachep->nodelists[nid];
if (ac->avail) {
spin_lock(&rl3->list_lock);
- free_block(cachep, ac->entry, ac->avail, node);
+ free_block(cachep, ac->entry, ac->avail, nid);
ac->avail = 0;
spin_unlock(&rl3->list_lock);
}
@@ -811,7 +815,7 @@ static inline void __drain_alien_cache(k
static void drain_alien_cache(kmem_cache_t *cachep, struct kmem_list3 *l3)
{
- int i=0;
+ int i = 0;
struct array_cache *ac;
unsigned long flags;
@@ -825,72 +829,74 @@ static void drain_alien_cache(kmem_cache
}
}
#else
-#define alloc_alien_cache(node, limit) do { } while (0)
-#define free_alien_cache(ac_ptr) do { } while (0)
-#define drain_alien_cache(cachep, l3) do { } while (0)
+#define alloc_alien_cache(nid, limit) do { } while (0)
+#define free_alien_cache(ac_ptr) do { } while (0)
+#define drain_alien_cache(cachep, l3) do { } while (0)
#endif
static int __devinit cpuup_callback(struct notifier_block *nfb,
- unsigned long action, void *hcpu)
+ unsigned long action, void *hcpu)
{
long cpu = (long)hcpu;
- kmem_cache_t* cachep;
+ kmem_cache_t *cachep;
struct kmem_list3 *l3 = NULL;
- int node = cpu_to_node(cpu);
+ int nid = cpu_to_node(cpu);
int memsize = sizeof(struct kmem_list3);
struct array_cache *nc = NULL;
switch (action) {
case CPU_UP_PREPARE:
down(&cache_chain_sem);
- /* we need to do this right in the beginning since
+ /*
+ * we need to do this right in the beginning since
* alloc_arraycache's are going to use this list.
* kmalloc_node allows us to add the slab to the right
* kmem_list3 and not this cpu's kmem_list3
*/
-
list_for_each_entry(cachep, &cache_chain, next) {
- /* setup the size64 kmemlist for cpu before we can
+ /*
+ * setup the size64 kmemlist for cpu before we can
* begin anything. Make sure some other cpu on this
* node has not already allocated this
*/
- if (!cachep->nodelists[node]) {
- if (!(l3 = kmalloc_node(memsize,
- GFP_KERNEL, node)))
+ if (!cachep->nodelists[nid]) {
+ if (!(l3 = kmalloc_node(memsize, GFP_KERNEL,
+ nid)))
goto bad;
kmem_list3_init(l3);
l3->next_reap = jiffies + REAPTIMEOUT_LIST3 +
- ((unsigned long)cachep)%REAPTIMEOUT_LIST3;
+ ((unsigned long)cachep) % REAPTIMEOUT_LIST3;
- cachep->nodelists[node] = l3;
+ cachep->nodelists[nid] = l3;
}
- spin_lock_irq(&cachep->nodelists[node]->list_lock);
- cachep->nodelists[node]->free_limit =
- (1 + nr_cpus_node(node)) *
+ spin_lock_irq(&cachep->nodelists[nid]->list_lock);
+ cachep->nodelists[nid]->free_limit =
+ (1 + nr_cpus_node(nid)) *
cachep->batchcount + cachep->num;
- spin_unlock_irq(&cachep->nodelists[node]->list_lock);
+ spin_unlock_irq(&cachep->nodelists[nid]->list_lock);
}
- /* Now we can go ahead with allocating the shared array's
- & array cache's */
+ /* Now we can allocate the shared arrays & array caches */
list_for_each_entry(cachep, &cache_chain, next) {
- nc = alloc_arraycache(node, cachep->limit,
- cachep->batchcount);
+ nc = alloc_arraycache(nid, cachep->limit,
+ cachep->batchcount);
if (!nc)
goto bad;
cachep->array[cpu] = nc;
- l3 = cachep->nodelists[node];
+ l3 = cachep->nodelists[nid];
BUG_ON(!l3);
if (!l3->shared) {
- if (!(nc = alloc_arraycache(node,
- cachep->shared*cachep->batchcount,
+ if (!(nc = alloc_arraycache(nid,
+ cachep->shared * cachep->batchcount,
0xbaadf00d)))
- goto bad;
+ goto bad;
- /* we are serialised from CPU_DEAD or
- CPU_UP_CANCELLED by the cpucontrol lock */
+ /*
+ * we are serialised from CPU_DEAD or
+ * CPU_UP_CANCELLED by the cpucontrol lock
+ */
l3->shared = nc;
}
}
@@ -909,12 +915,12 @@ static int __devinit cpuup_callback(stru
struct array_cache *nc;
cpumask_t mask;
- mask = node_to_cpumask(node);
+ mask = node_to_cpumask(nid);
spin_lock_irq(&cachep->spinlock);
/* cpu is dead; no one can alloc from it. */
nc = cachep->array[cpu];
cachep->array[cpu] = NULL;
- l3 = cachep->nodelists[node];
+ l3 = cachep->nodelists[nid];
if (!l3)
goto unlock_cache;
@@ -924,16 +930,16 @@ static int __devinit cpuup_callback(stru
/* Free limit for this kmem_list3 */
l3->free_limit -= cachep->batchcount;
if (nc)
- free_block(cachep, nc->entry, nc->avail, node);
+ free_block(cachep, nc->entry, nc->avail, nid);
if (!cpus_empty(mask)) {
- spin_unlock(&l3->list_lock);
- goto unlock_cache;
- }
+ spin_unlock(&l3->list_lock);
+ goto unlock_cache;
+ }
if (l3->shared) {
free_block(cachep, l3->shared->entry,
- l3->shared->avail, node);
+ l3->shared->avail, nid);
kfree(l3->shared);
l3->shared = NULL;
}
@@ -944,8 +950,8 @@ static int __devinit cpuup_callback(stru
}
/* free slabs belonging to this node */
- if (__node_shrink(cachep, node)) {
- cachep->nodelists[node] = NULL;
+ if (__node_shrink(cachep, nid)) {
+ cachep->nodelists[nid] = NULL;
spin_unlock(&l3->list_lock);
kfree(l3);
} else {
@@ -970,23 +976,23 @@ static struct notifier_block cpucache_no
/*
* swap the static kmem_list3 with kmalloced memory
*/
-static void init_list(kmem_cache_t *cachep, struct kmem_list3 *list,
- int nodeid)
+static void init_list(kmem_cache_t *cachep, struct kmem_list3 *list, int nid)
{
struct kmem_list3 *ptr;
- BUG_ON(cachep->nodelists[nodeid] != list);
- ptr = kmalloc_node(sizeof(struct kmem_list3), GFP_KERNEL, nodeid);
+ BUG_ON(cachep->nodelists[nid] != list);
+ ptr = kmalloc_node(sizeof(struct kmem_list3), GFP_KERNEL, nid);
BUG_ON(!ptr);
local_irq_disable();
memcpy(ptr, list, sizeof(struct kmem_list3));
- MAKE_ALL_LISTS(cachep, ptr, nodeid);
- cachep->nodelists[nodeid] = ptr;
+ MAKE_ALL_LISTS(cachep, ptr, nid);
+ cachep->nodelists[nid] = ptr;
local_irq_enable();
}
-/* Initialisation.
+/*
+ * Initialization.
* Called after the gfp() functions have been enabled, and before smp_init().
*/
void __init kmem_cache_init(void)
@@ -1009,7 +1015,8 @@ void __init kmem_cache_init(void)
if (num_physpages > (32 << 20) >> PAGE_SHIFT)
slab_break_gfp_order = BREAK_GFP_ORDER_HI;
- /* Bootstrap is tricky, because several objects are allocated
+ /*
+ * Bootstrap is tricky, because several objects are allocated
* from caches that do not exist yet:
* 1) initialize the cache_cache cache: it contains the kmem_cache_t
* structures of all caches, except cache_cache itself: cache_cache
@@ -1026,7 +1033,7 @@ void __init kmem_cache_init(void)
* kmalloc cache with kmalloc allocated arrays.
* 5) Replace the __init data for kmem_list3 for cache_cache and
* the other cache's with kmalloc allocated memory.
- * 6) Resize the head arrays of the kmalloc caches to their final sizes.
+ * 6) Resize head arrays of the kmalloc caches to their final sizes.
*/
/* 1) create the cache_cache */
@@ -1040,24 +1047,24 @@ void __init kmem_cache_init(void)
cache_cache.objsize = ALIGN(cache_cache.objsize, cache_line_size());
cache_estimate(0, cache_cache.objsize, cache_line_size(), 0,
- &left_over, &cache_cache.num);
+ &left_over, &cache_cache.num);
if (!cache_cache.num)
BUG();
- cache_cache.colour = left_over/cache_cache.colour_off;
+ cache_cache.colour = left_over / cache_cache.colour_off;
cache_cache.colour_next = 0;
- cache_cache.slab_size = ALIGN(cache_cache.num*sizeof(kmem_bufctl_t) +
+ cache_cache.slab_size = ALIGN(cache_cache.num * sizeof(kmem_bufctl_t) +
sizeof(struct slab), cache_line_size());
/* 2+3) create the kmalloc caches */
sizes = malloc_sizes;
names = cache_names;
- /* Initialize the caches that provide memory for the array cache
+ /*
+ * Initialize the caches that provide memory for the array cache
* and the kmem_list3 structures first.
* Without this, further allocations will bug
*/
-
sizes[INDEX_AC].cs_cachep = kmem_cache_create(names[INDEX_AC].name,
sizes[INDEX_AC].cs_size, ARCH_KMALLOC_MINALIGN,
(ARCH_KMALLOC_FLAGS | SLAB_PANIC), NULL, NULL);
@@ -1097,44 +1104,42 @@ void __init kmem_cache_init(void)
}
/* 4) Replace the bootstrap head arrays */
{
- void * ptr;
+ void *ptr;
ptr = kmalloc(sizeof(struct arraycache_init), GFP_KERNEL);
local_irq_disable();
BUG_ON(ac_data(&cache_cache) != &initarray_cache.cache);
memcpy(ptr, ac_data(&cache_cache),
- sizeof(struct arraycache_init));
+ sizeof(struct arraycache_init));
cache_cache.array[smp_processor_id()] = ptr;
local_irq_enable();
ptr = kmalloc(sizeof(struct arraycache_init), GFP_KERNEL);
local_irq_disable();
- BUG_ON(ac_data(malloc_sizes[INDEX_AC].cs_cachep)
- != &initarray_generic.cache);
+ BUG_ON(ac_data(malloc_sizes[INDEX_AC].cs_cachep) !=
+ &initarray_generic.cache);
memcpy(ptr, ac_data(malloc_sizes[INDEX_AC].cs_cachep),
- sizeof(struct arraycache_init));
+ sizeof(struct arraycache_init));
malloc_sizes[INDEX_AC].cs_cachep->array[smp_processor_id()] =
- ptr;
+ ptr;
local_irq_enable();
}
/* 5) Replace the bootstrap kmem_list3's */
{
- int node;
+ int nid;
/* Replace the static kmem_list3 structures for the boot cpu */
init_list(&cache_cache, &initkmem_list3[CACHE_CACHE],
- numa_node_id());
+ numa_node_id());
- for_each_online_node(node) {
+ for_each_online_node(nid) {
init_list(malloc_sizes[INDEX_AC].cs_cachep,
- &initkmem_list3[SIZE_AC+node], node);
+ &initkmem_list3[SIZE_AC+nid], nid);
- if (INDEX_AC != INDEX_L3) {
+ if (INDEX_AC != INDEX_L3)
init_list(malloc_sizes[INDEX_L3].cs_cachep,
- &initkmem_list3[SIZE_L3+node],
- node);
- }
+ &initkmem_list3[SIZE_L3+nid], nid);
}
}
@@ -1150,12 +1155,14 @@ void __init kmem_cache_init(void)
/* Done! */
g_cpucache_up = FULL;
- /* Register a cpu startup notifier callback
+ /*
+ * Register a cpu startup notifier callback
* that initializes ac_data for all new cpus
*/
register_cpu_notifier(&cpucache_notifier);
- /* The reap timers are started later, with a module init call:
+ /*
+ * The reap timers are started later, with a module init call:
* That part of the kernel is not yet operational.
*/
}
@@ -1164,16 +1171,12 @@ static int __init cpucache_init(void)
{
int cpu;
- /*
- * Register the timers that return unneeded
- * pages to gfp.
- */
+ /* Register the timers that return unneeded pages to gfp */
for_each_online_cpu(cpu)
start_cpu_timer(cpu);
return 0;
}
-
__initcall(cpucache_init);
/*
@@ -1183,23 +1186,22 @@ __initcall(cpucache_init);
* did not request dmaable memory, we might get it, but that
* would be relatively rare and ignorable.
*/
-static void *kmem_getpages(kmem_cache_t *cachep, gfp_t flags, int nodeid)
+static void *kmem_getpages(kmem_cache_t *cachep, gfp_t flags, int nid)
{
struct page *page;
void *addr;
int i;
flags |= cachep->gfpflags;
- if (likely(nodeid == -1)) {
+ if (likely(nid == -1))
page = alloc_pages(flags, cachep->gfporder);
- } else {
- page = alloc_pages_node(nodeid, flags, cachep->gfporder);
- }
+ else
+ page = alloc_pages_node(nid, flags, cachep->gfporder);
if (!page)
return NULL;
addr = page_address(page);
- i = (1 << cachep->gfporder);
+ i = 1 << cachep->gfporder;
if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
atomic_add(i, &slab_reclaim_pages);
add_page_state(nr_slab, i);
@@ -1215,7 +1217,7 @@ static void *kmem_getpages(kmem_cache_t
*/
static void kmem_freepages(kmem_cache_t *cachep, void *addr)
{
- unsigned long i = (1<<cachep->gfporder);
+ unsigned long i = 1 << cachep->gfporder;
struct page *page = virt_to_page(addr);
const unsigned long nr_freed = i;
@@ -1228,13 +1230,13 @@ static void kmem_freepages(kmem_cache_t
if (current->reclaim_state)
current->reclaim_state->reclaimed_slab += nr_freed;
free_pages((unsigned long)addr, cachep->gfporder);
- if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
- atomic_sub(1<<cachep->gfporder, &slab_reclaim_pages);
+ if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
+ atomic_sub(1 << cachep->gfporder, &slab_reclaim_pages);
}
static void kmem_rcu_free(struct rcu_head *head)
{
- struct slab_rcu *slab_rcu = (struct slab_rcu *) head;
+ struct slab_rcu *slab_rcu = (struct slab_rcu *)head;
kmem_cache_t *cachep = slab_rcu->cachep;
kmem_freepages(cachep, slab_rcu->addr);
@@ -1246,19 +1248,19 @@ static void kmem_rcu_free(struct rcu_hea
#ifdef CONFIG_DEBUG_PAGEALLOC
static void store_stackinfo(kmem_cache_t *cachep, unsigned long *addr,
- unsigned long caller)
+ unsigned long caller)
{
int size = obj_reallen(cachep);
- addr = (unsigned long *)&((char*)addr)[obj_dbghead(cachep)];
+ addr = (unsigned long *)&((char *)addr)[obj_dbghead(cachep)];
- if (size < 5*sizeof(unsigned long))
+ if (size < 5 * sizeof(unsigned long))
return;
- *addr++=0x12345678;
- *addr++=caller;
- *addr++=smp_processor_id();
- size -= 3*sizeof(unsigned long);
+ *addr++ = 0x12345678;
+ *addr++ = caller;
+ *addr++ = smp_processor_id();
+ size -= 3 * sizeof(unsigned long);
{
unsigned long *sptr = &caller;
unsigned long svalue;
@@ -1266,34 +1268,32 @@ static void store_stackinfo(kmem_cache_t
while (!kstack_end(sptr)) {
svalue = *sptr++;
if (kernel_text_address(svalue)) {
- *addr++=svalue;
+ *addr++ = svalue;
size -= sizeof(unsigned long);
if (size <= sizeof(unsigned long))
break;
}
}
-
}
- *addr++=0x87654321;
+ *addr++ = 0x87654321;
}
#endif
static void poison_obj(kmem_cache_t *cachep, void *addr, unsigned char val)
{
int size = obj_reallen(cachep);
- addr = &((char*)addr)[obj_dbghead(cachep)];
+ addr = &((char *)addr)[obj_dbghead(cachep)];
memset(addr, val, size);
- *(unsigned char *)(addr+size-1) = POISON_END;
+ *(unsigned char *)(addr + size - 1) = POISON_END;
}
static void dump_line(char *data, int offset, int limit)
{
int i;
printk(KERN_ERR "%03x:", offset);
- for (i=0;i<limit;i++) {
+ for (i = 0; i < limit; i++)
printk(" %02x", (unsigned char)data[offset+i]);
- }
printk("\n");
}
#endif
@@ -1307,24 +1307,24 @@ static void print_objinfo(kmem_cache_t *
if (cachep->flags & SLAB_RED_ZONE) {
printk(KERN_ERR "Redzone: 0x%lx/0x%lx.\n",
- *dbg_redzone1(cachep, objp),
- *dbg_redzone2(cachep, objp));
+ *dbg_redzone1(cachep, objp),
+ *dbg_redzone2(cachep, objp));
}
if (cachep->flags & SLAB_STORE_USER) {
printk(KERN_ERR "Last user: [<%p>]",
- *dbg_userword(cachep, objp));
+ *dbg_userword(cachep, objp));
print_symbol("(%s)",
(unsigned long)*dbg_userword(cachep, objp));
printk("\n");
}
- realobj = (char*)objp+obj_dbghead(cachep);
+ realobj = (char *)objp + obj_dbghead(cachep);
size = obj_reallen(cachep);
- for (i=0; i<size && lines;i+=16, lines--) {
+ for (i = 0; i < size && lines; i += 16, lines--) {
int limit;
limit = 16;
- if (i+limit > size)
- limit = size-i;
+ if (i + limit > size)
+ limit = size - i;
dump_line(realobj, i, limit);
}
}
@@ -1335,27 +1335,27 @@ static void check_poison_obj(kmem_cache_
int size, i;
int lines = 0;
- realobj = (char*)objp+obj_dbghead(cachep);
+ realobj = (char *)objp + obj_dbghead(cachep);
size = obj_reallen(cachep);
- for (i=0;i<size;i++) {
+ for (i = 0; i < size; i++) {
char exp = POISON_FREE;
- if (i == size-1)
+ if (i == size - 1)
exp = POISON_END;
if (realobj[i] != exp) {
int limit;
/* Mismatch ! */
/* Print header */
if (lines == 0) {
- printk(KERN_ERR "Slab corruption: start=%p, len=%d\n",
- realobj, size);
+ printk(KERN_ERR "Slab corruption: start=%p, "
+ "len=%d\n", realobj, size);
print_objinfo(cachep, objp, 0);
}
/* Hexdump the affected line */
- i = (i/16)*16;
+ i = (i / 16) * 16;
limit = 16;
- if (i+limit > size)
- limit = size-i;
+ if (i + limit > size)
+ limit = size - i;
dump_line(realobj, i, limit);
i += 16;
lines++;
@@ -1365,36 +1365,35 @@ static void check_poison_obj(kmem_cache_
}
}
if (lines != 0) {
- /* Print some data about the neighboring objects, if they
- * exist:
- */
+ /* Print data about the neighboring objects, if they exist */
struct slab *slabp = GET_PAGE_SLAB(virt_to_page(objp));
int objnr;
- objnr = (objp-slabp->s_mem)/cachep->objsize;
+ objnr = (objp - slabp->s_mem) / cachep->objsize;
if (objnr) {
- objp = slabp->s_mem+(objnr-1)*cachep->objsize;
- realobj = (char*)objp+obj_dbghead(cachep);
+ objp = slabp->s_mem + (objnr - 1) * cachep->objsize;
+ realobj = (char *)objp + obj_dbghead(cachep);
printk(KERN_ERR "Prev obj: start=%p, len=%d\n",
- realobj, size);
+ realobj, size);
print_objinfo(cachep, objp, 2);
}
- if (objnr+1 < cachep->num) {
- objp = slabp->s_mem+(objnr+1)*cachep->objsize;
- realobj = (char*)objp+obj_dbghead(cachep);
+ if (objnr + 1 < cachep->num) {
+ objp = slabp->s_mem + (objnr + 1) * cachep->objsize;
+ realobj = (char *)objp + obj_dbghead(cachep);
printk(KERN_ERR "Next obj: start=%p, len=%d\n",
- realobj, size);
+ realobj, size);
print_objinfo(cachep, objp, 2);
}
}
}
#endif
-/* Destroy all the objs in a slab, and release the mem back to the system.
+/*
+ * Destroy all the objs in a slab, and release the mem back to the system.
* Before calling the slab must have been unlinked from the cache.
* The cache-lock is not held/needed.
*/
-static void slab_destroy (kmem_cache_t *cachep, struct slab *slabp)
+static void slab_destroy(kmem_cache_t *cachep, struct slab *slabp)
{
void *addr = slabp->s_mem - slabp->colouroff;
@@ -1405,8 +1404,10 @@ static void slab_destroy (kmem_cache_t *
if (cachep->flags & SLAB_POISON) {
#ifdef CONFIG_DEBUG_PAGEALLOC
- if ((cachep->objsize%PAGE_SIZE)==0 && OFF_SLAB(cachep))
- kernel_map_pages(virt_to_page(objp), cachep->objsize/PAGE_SIZE,1);
+ if ((cachep->objsize % PAGE_SIZE) == 0 &&
+ OFF_SLAB(cachep))
+ kernel_map_pages(virt_to_page(objp),
+ cachep->objsize/PAGE_SIZE, 1);
else
check_poison_obj(cachep, objp);
#else
@@ -1422,13 +1423,13 @@ static void slab_destroy (kmem_cache_t *
"was overwritten");
}
if (cachep->dtor && !(cachep->flags & SLAB_POISON))
- (cachep->dtor)(objp+obj_dbghead(cachep), cachep, 0);
+ (cachep->dtor)(objp + obj_dbghead(cachep), cachep, 0);
}
#else
if (cachep->dtor) {
int i;
for (i = 0; i < cachep->num; i++) {
- void* objp = slabp->s_mem+cachep->objsize*i;
+ void *objp = slabp->s_mem + cachep->objsize * i;
(cachep->dtor)(objp, cachep, 0);
}
}
@@ -1437,7 +1438,7 @@ static void slab_destroy (kmem_cache_t *
if (unlikely(cachep->flags & SLAB_DESTROY_BY_RCU)) {
struct slab_rcu *slab_rcu;
- slab_rcu = (struct slab_rcu *) slabp;
+ slab_rcu = (struct slab_rcu *)slabp;
slab_rcu->cachep = cachep;
slab_rcu->addr = addr;
call_rcu(&slab_rcu->head, kmem_rcu_free);
@@ -1448,21 +1449,70 @@ static void slab_destroy (kmem_cache_t *
}
}
-/* For setting up all the kmem_list3s for cache whose objsize is same
- as size of kmem_list3. */
+/*
+ * For setting up all the kmem_list3s for cache whose objsize is same
+ * as size of kmem_list3.
+ */
static inline void set_up_list3s(kmem_cache_t *cachep, int index)
{
- int node;
+ int nid;
- for_each_online_node(node) {
- cachep->nodelists[node] = &initkmem_list3[index+node];
- cachep->nodelists[node]->next_reap = jiffies +
+ for_each_online_node(nid) {
+ cachep->nodelists[nid] = &initkmem_list3[index + nid];
+ cachep->nodelists[nid]->next_reap = jiffies +
REAPTIMEOUT_LIST3 +
- ((unsigned long)cachep)%REAPTIMEOUT_LIST3;
+ ((unsigned long)cachep) % REAPTIMEOUT_LIST3;
}
}
/**
+ * calculate_slab_order - calculate size (page order) of slabs and the number
+ * of objects per slab.
+ *
+ * This could be made much more intelligent. For now, try to avoid using
+ * high order pages for slabs. When the gfp() functions are more friendly
+ * towards high-order requests, this should be changed.
+ */
+static inline size_t calculate_slab_order(kmem_cache_t *cachep, size_t size,
+ size_t align, gfp_t flags)
+{
+ size_t left_over = 0;
+
+ for ( ; ; cachep->gfporder++) {
+ unsigned int num;
+ size_t remainder;
+
+ if (cachep->gfporder > MAX_GFP_ORDER) {
+ cachep->num = 0;
+ break;
+ }
+
+ cache_estimate(cachep->gfporder, size, align, flags,
+ &remainder, &num);
+ if (!num)
+ continue;
+ /* More than offslab_limit objects will cause problems */
+ if (flags & CFLGS_OFF_SLAB && cachep->num > offslab_limit)
+ break;
+
+ cachep->num = num;
+ left_over = remainder;
+
+ /*
+ * Large number of objects is good, but very large slabs are
+ * currently bad for the gfp()s.
+ */
+ if (cachep->gfporder >= slab_break_gfp_order)
+ break;
+
+ if ((left_over * 8) <= (PAGE_SIZE << cachep->gfporder))
+ break; /* Acceptable internal fragmentation */
+ }
+
+ return left_over;
+}
+
+/**
* kmem_cache_create - Create a cache.
* @name: A string which is used in /proc/slabinfo to identify this cache.
* @size: The size of objects to be created in this cache.
@@ -1477,9 +1527,9 @@ static inline void set_up_list3s(kmem_ca
* and the @dtor is run before the pages are handed back.
*
* @name must be valid until the cache is destroyed. This implies that
- * the module calling this has to destroy the cache before getting
+ * the module calling this has to destroy the cache before getting
* unloaded.
- *
+ *
* The flags are
*
* %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
@@ -1495,32 +1545,28 @@ static inline void set_up_list3s(kmem_ca
* cacheline. This can be beneficial if you're counting cycles as closely
* as davem.
*/
-kmem_cache_t *
-kmem_cache_create (const char *name, size_t size, size_t align,
- unsigned long flags, void (*ctor)(void*, kmem_cache_t *, unsigned long),
- void (*dtor)(void*, kmem_cache_t *, unsigned long))
+kmem_cache_t *kmem_cache_create(const char *name, size_t size, size_t align,
+ unsigned long flags,
+ void (*ctor)(void *, kmem_cache_t *, unsigned long),
+ void (*dtor)(void *, kmem_cache_t *, unsigned long))
{
- size_t left_over, slab_size, ralign;
+ size_t left_over, slab_size, aligned_slab_size, ralign;
kmem_cache_t *cachep = NULL;
- struct list_head *p;
+ kmem_cache_t *pc;
/*
* Sanity checks... these are all serious usage bugs.
*/
- if ((!name) ||
- in_interrupt() ||
- (size < BYTES_PER_WORD) ||
- (size > (1<<MAX_OBJ_ORDER)*PAGE_SIZE) ||
- (dtor && !ctor)) {
- printk(KERN_ERR "%s: Early error in slab %s\n",
- __FUNCTION__, name);
- BUG();
- }
+ if (!name || in_interrupt() || (size < BYTES_PER_WORD) ||
+ (size > (1 << MAX_OBJ_ORDER) * PAGE_SIZE) || (dtor && !ctor)) {
+ printk(KERN_ERR "%s: Early error in slab %s\n",
+ __FUNCTION__, name);
+ BUG();
+ }
down(&cache_chain_sem);
- list_for_each(p, &cache_chain) {
- kmem_cache_t *pc = list_entry(p, kmem_cache_t, next);
+ list_for_each_entry(pc, &cache_chain, next) {
mm_segment_t old_fs = get_fs();
char tmp;
int res;
@@ -1542,7 +1588,7 @@ kmem_cache_create (const char *name, siz
if (!strcmp(pc->name,name)) {
printk("kmem_cache_create: duplicate cache %s\n", name);
dump_stack();
- goto oops;
+ goto out;
}
}
@@ -1562,7 +1608,8 @@ kmem_cache_create (const char *name, siz
* above the next power of two: caches with object sizes just above a
* power of two have a significant amount of internal fragmentation.
*/
- if ((size < 4096 || fls(size-1) == fls(size-1+3*BYTES_PER_WORD)))
+ if (size < RED_ZONE_LIMIT ||
+ fls(size - 1) == fls(size - 1 + 3 * BYTES_PER_WORD))
flags |= SLAB_RED_ZONE|SLAB_STORE_USER;
if (!(flags & SLAB_DESTROY_BY_RCU))
flags |= SLAB_POISON;
@@ -1580,24 +1627,26 @@ kmem_cache_create (const char *name, siz
if (flags & ~CREATE_MASK)
BUG();
- /* Check that size is in terms of words. This is needed to avoid
+ /*
+ * Check that size is in terms of words. This is needed to avoid
* unaligned accesses for some archs when redzoning is used, and makes
* sure any on-slab bufctl's are also correctly aligned.
*/
- if (size & (BYTES_PER_WORD-1)) {
- size += (BYTES_PER_WORD-1);
- size &= ~(BYTES_PER_WORD-1);
+ if (size & (BYTES_PER_WORD - 1)) {
+ size += (BYTES_PER_WORD - 1);
+ size &= ~(BYTES_PER_WORD - 1);
}
/* calculate out the final buffer alignment: */
/* 1) arch recommendation: can be overridden for debug */
if (flags & SLAB_HWCACHE_ALIGN) {
- /* Default alignment: as specified by the arch code.
+ /*
+ * Default alignment: as specified by the arch code.
* Except if an object is really small, then squeeze multiple
* objects into one cacheline.
*/
ralign = cache_line_size();
- while (size <= ralign/2)
+ while (size <= ralign / 2)
ralign /= 2;
} else {
ralign = BYTES_PER_WORD;
@@ -1614,7 +1663,8 @@ kmem_cache_create (const char *name, siz
if (ralign > BYTES_PER_WORD)
flags &= ~(SLAB_RED_ZONE|SLAB_STORE_USER);
}
- /* 4) Store it. Note that the debug code below can reduce
+ /*
+ * 4) Store it. Note that the debug code below can reduce
* the alignment to BYTES_PER_WORD.
*/
align = ralign;
@@ -1622,7 +1672,7 @@ kmem_cache_create (const char *name, siz
/* Get cache's description obj. */
cachep = (kmem_cache_t *) kmem_cache_alloc(&cache_cache, SLAB_KERNEL);
if (!cachep)
- goto oops;
+ goto out;
memset(cachep, 0, sizeof(kmem_cache_t));
#if DEBUG
@@ -1634,10 +1684,11 @@ kmem_cache_create (const char *name, siz
/* add space for red zone words */
cachep->dbghead += BYTES_PER_WORD;
- size += 2*BYTES_PER_WORD;
+ size += 2 * BYTES_PER_WORD;
}
if (flags & SLAB_STORE_USER) {
- /* user store requires word alignment and
+ /*
+ * user store requires word alignment and
* one word storage behind the end of the real
* object.
*/
@@ -1645,7 +1696,8 @@ kmem_cache_create (const char *name, siz
size += BYTES_PER_WORD;
}
#if FORCED_DEBUG && defined(CONFIG_DEBUG_PAGEALLOC)
- if (size >= malloc_sizes[INDEX_L3+1].cs_size && cachep->reallen > cache_line_size() && size < PAGE_SIZE) {
+ if (size >= malloc_sizes[INDEX_L3+1].cs_size &&
+ cachep->reallen > cache_line_size() && size < PAGE_SIZE) {
cachep->dbghead += PAGE_SIZE - size;
size = PAGE_SIZE;
}
@@ -1653,7 +1705,7 @@ kmem_cache_create (const char *name, siz
#endif
/* Determine if the slab management is 'on' or 'off' slab. */
- if (size >= (PAGE_SIZE>>3))
+ if (size >= (PAGE_SIZE >> 3))
/*
* Size is large, assume best to place the slab management obj
* off-slab (should allow better packing of objs).
@@ -1665,75 +1717,35 @@ kmem_cache_create (const char *name, siz
if ((flags & SLAB_RECLAIM_ACCOUNT) && size <= PAGE_SIZE) {
/*
* A VFS-reclaimable slab tends to have most allocations
- * as GFP_NOFS and we really don't want to have to be allocating
+ * as GFP_NOFS & we really don't want to have to be allocating
* higher-order pages when we are unable to shrink dcache.
*/
cachep->gfporder = 0;
cache_estimate(cachep->gfporder, size, align, flags,
- &left_over, &cachep->num);
- } else {
- /*
- * Calculate size (in pages) of slabs, and the num of objs per
- * slab. This could be made much more intelligent. For now,
- * try to avoid using high page-orders for slabs. When the
- * gfp() funcs are more friendly towards high-order requests,
- * this should be changed.
- */
- do {
- unsigned int break_flag = 0;
-cal_wastage:
- cache_estimate(cachep->gfporder, size, align, flags,
- &left_over, &cachep->num);
- if (break_flag)
- break;
- if (cachep->gfporder >= MAX_GFP_ORDER)
- break;
- if (!cachep->num)
- goto next;
- if (flags & CFLGS_OFF_SLAB &&
- cachep->num > offslab_limit) {
- /* This num of objs will cause problems. */
- cachep->gfporder--;
- break_flag++;
- goto cal_wastage;
- }
-
- /*
- * Large num of objs is good, but v. large slabs are
- * currently bad for the gfp()s.
- */
- if (cachep->gfporder >= slab_break_gfp_order)
- break;
-
- if ((left_over*8) <= (PAGE_SIZE<<cachep->gfporder))
- break; /* Acceptable internal fragmentation. */
-next:
- cachep->gfporder++;
- } while (1);
- }
+ &left_over, &cachep->num);
+ } else
+ left_over = calculate_slab_order(cachep, size, align, flags);
if (!cachep->num) {
printk("kmem_cache_create: couldn't create cache %s.\n", name);
kmem_cache_free(&cache_cache, cachep);
cachep = NULL;
- goto oops;
+ goto out;
}
- slab_size = ALIGN(cachep->num*sizeof(kmem_bufctl_t)
- + sizeof(struct slab), align);
+ slab_size = cachep->num * sizeof(kmem_bufctl_t) + sizeof(struct slab);
+ aligned_slab_size = ALIGN(slab_size, align);
/*
* If the slab has been placed off-slab, and we have enough space then
* move it on-slab. This is at the expense of any extra colouring.
*/
- if (flags & CFLGS_OFF_SLAB && left_over >= slab_size) {
+ if (flags & CFLGS_OFF_SLAB && left_over >= aligned_slab_size) {
flags &= ~CFLGS_OFF_SLAB;
- left_over -= slab_size;
- }
-
- if (flags & CFLGS_OFF_SLAB) {
- /* really off slab. No need for manual alignment */
- slab_size = cachep->num*sizeof(kmem_bufctl_t)+sizeof(struct slab);
+ left_over -= aligned_slab_size;
}
+ /* On slab, need manual alignment */
+ if (!(flags & CFLGS_OFF_SLAB))
+ slab_size = aligned_slab_size;
cachep->colour_off = cache_line_size();
/* Offset must be a multiple of the alignment. */
@@ -1761,14 +1773,16 @@ next:
enable_cpucache(cachep);
} else {
if (g_cpucache_up == NONE) {
- /* Note: the first kmem_cache_create must create
+ /*
+ * Note: the first kmem_cache_create must create
* the cache that's used by kmalloc(24), otherwise
* the creation of further caches will BUG().
*/
cachep->array[smp_processor_id()] =
&initarray_generic.cache;
- /* If the cache that's used by
+ /*
+ * If the cache that's used by
* kmalloc(sizeof(kmem_list3)) is the first cache,
* then we need to set up all its list3s, otherwise
* the creation of further caches will BUG().
@@ -1787,14 +1801,13 @@ next:
set_up_list3s(cachep, SIZE_L3);
g_cpucache_up = PARTIAL_L3;
} else {
- int node;
- for_each_online_node(node) {
-
- cachep->nodelists[node] =
+ int nid;
+ for_each_online_node(nid) {
+ cachep->nodelists[nid] =
kmalloc_node(sizeof(struct kmem_list3),
- GFP_KERNEL, node);
- BUG_ON(!cachep->nodelists[node]);
- kmem_list3_init(cachep->nodelists[node]);
+ GFP_KERNEL, nid);
+ BUG_ON(!cachep->nodelists[nid]);
+ kmem_list3_init(cachep->nodelists[nid]);
}
}
}
@@ -1809,15 +1822,14 @@ next:
ac_data(cachep)->touched = 0;
cachep->batchcount = 1;
cachep->limit = BOOT_CPUCACHE_ENTRIES;
- }
+ }
/* cache setup completed, link it into the list */
list_add(&cachep->next, &cache_chain);
unlock_cpu_hotplug();
-oops:
+out:
if (!cachep && (flags & SLAB_PANIC))
- panic("kmem_cache_create(): failed to create slab `%s'\n",
- name);
+ panic("%s: failed to create slab `%s'\n", __FUNCTION__, name);
up(&cache_chain_sem);
return cachep;
}
@@ -1842,25 +1854,25 @@ static void check_spinlock_acquired(kmem
#endif
}
-static inline void check_spinlock_acquired_node(kmem_cache_t *cachep, int node)
+static inline void check_spinlock_acquired_node(kmem_cache_t *cachep, int nid)
{
#ifdef CONFIG_SMP
check_irq_off();
- assert_spin_locked(&cachep->nodelists[node]->list_lock);
+ assert_spin_locked(&cachep->nodelists[nid]->list_lock);
#endif
}
#else
-#define check_irq_off() do { } while(0)
-#define check_irq_on() do { } while(0)
-#define check_spinlock_acquired(x) do { } while(0)
-#define check_spinlock_acquired_node(x, y) do { } while(0)
+#define check_irq_off() do { } while(0)
+#define check_irq_on() do { } while(0)
+#define check_spinlock_acquired(x) do { } while(0)
+#define check_spinlock_acquired_node(x, y) do { } while(0)
#endif
/*
* Waits for all CPUs to execute func().
*/
-static void smp_call_function_all_cpus(void (*func) (void *arg), void *arg)
+static void smp_call_function_all_cpus(void (*func)(void *arg), void *arg)
{
check_irq_on();
preempt_disable();
@@ -1875,36 +1887,36 @@ static void smp_call_function_all_cpus(v
preempt_enable();
}
-static void drain_array_locked(kmem_cache_t* cachep,
- struct array_cache *ac, int force, int node);
+static void drain_array_locked(kmem_cache_t *cachep, struct array_cache *ac,
+ int force, int nid);
static void do_drain(void *arg)
{
- kmem_cache_t *cachep = (kmem_cache_t*)arg;
+ kmem_cache_t *cachep = (kmem_cache_t *)arg;
struct array_cache *ac;
- int node = numa_node_id();
+ int nid = numa_node_id();
check_irq_off();
ac = ac_data(cachep);
- spin_lock(&cachep->nodelists[node]->list_lock);
- free_block(cachep, ac->entry, ac->avail, node);
- spin_unlock(&cachep->nodelists[node]->list_lock);
+ spin_lock(&cachep->nodelists[nid]->list_lock);
+ free_block(cachep, ac->entry, ac->avail, nid);
+ spin_unlock(&cachep->nodelists[nid]->list_lock);
ac->avail = 0;
}
static void drain_cpu_caches(kmem_cache_t *cachep)
{
struct kmem_list3 *l3;
- int node;
+ int nid;
smp_call_function_all_cpus(do_drain, cachep);
check_irq_on();
spin_lock_irq(&cachep->spinlock);
- for_each_online_node(node) {
- l3 = cachep->nodelists[node];
+ for_each_online_node(nid) {
+ l3 = cachep->nodelists[nid];
if (l3) {
spin_lock(&l3->list_lock);
- drain_array_locked(cachep, l3->shared, 1, node);
+ drain_array_locked(cachep, l3->shared, 1, nid);
spin_unlock(&l3->list_lock);
if (l3->alien)
drain_alien_cache(cachep, l3);
@@ -1913,10 +1925,10 @@ static void drain_cpu_caches(kmem_cache_
spin_unlock_irq(&cachep->spinlock);
}
-static int __node_shrink(kmem_cache_t *cachep, int node)
+static int __node_shrink(kmem_cache_t *cachep, int nid)
{
struct slab *slabp;
- struct kmem_list3 *l3 = cachep->nodelists[node];
+ struct kmem_list3 *l3 = cachep->nodelists[nid];
int ret;
for (;;) {
@@ -1938,11 +1950,17 @@ static int __node_shrink(kmem_cache_t *c
slab_destroy(cachep, slabp);
spin_lock_irq(&l3->list_lock);
}
- ret = !list_empty(&l3->slabs_full) ||
- !list_empty(&l3->slabs_partial);
+ ret = !list_empty(&l3->slabs_full) || !list_empty(&l3->slabs_partial);
return ret;
}
+/**
+ * __cache_shrink - Release all free slabs
+ * @cachep: The cache to shrink.
+ *
+ * Return 1 if there are still partial or full slabs belonging to this cache
+ * Return 0 if there are no more slabs belonging to this cache
+ */
static int __cache_shrink(kmem_cache_t *cachep)
{
int ret = 0, i = 0;
@@ -1959,7 +1977,7 @@ static int __cache_shrink(kmem_cache_t *
spin_unlock_irq(&l3->list_lock);
}
}
- return (ret ? 1 : 0);
+ return ret ? 1 : 0;
}
/**
@@ -1995,7 +2013,7 @@ EXPORT_SYMBOL(kmem_cache_shrink);
* The caller must guarantee that noone will allocate memory from the cache
* during the kmem_cache_destroy().
*/
-int kmem_cache_destroy(kmem_cache_t * cachep)
+int kmem_cache_destroy(kmem_cache_t *cachep)
{
int i;
struct kmem_list3 *l3;
@@ -2008,9 +2026,7 @@ int kmem_cache_destroy(kmem_cache_t * ca
/* Find the cache in the chain of caches. */
down(&cache_chain_sem);
- /*
- * the chain is never empty, cache_cache is never destroyed
- */
+ /* the chain is never empty, cache_cache is never destroyed */
list_del(&cachep->next);
up(&cache_chain_sem);
@@ -2046,8 +2062,8 @@ int kmem_cache_destroy(kmem_cache_t * ca
EXPORT_SYMBOL(kmem_cache_destroy);
/* Get the memory for a slab management obj. */
-static struct slab* alloc_slabmgmt(kmem_cache_t *cachep, void *objp,
- int colour_off, gfp_t local_flags)
+static struct slab *alloc_slabmgmt(kmem_cache_t *cachep, void *objp,
+ int colour_off, gfp_t local_flags)
{
struct slab *slabp;
@@ -2057,28 +2073,28 @@ static struct slab* alloc_slabmgmt(kmem_
if (!slabp)
return NULL;
} else {
- slabp = objp+colour_off;
+ slabp = objp + colour_off;
colour_off += cachep->slab_size;
}
slabp->inuse = 0;
slabp->colouroff = colour_off;
- slabp->s_mem = objp+colour_off;
+ slabp->s_mem = objp + colour_off;
return slabp;
}
static inline kmem_bufctl_t *slab_bufctl(struct slab *slabp)
{
- return (kmem_bufctl_t *)(slabp+1);
+ return (kmem_bufctl_t *)(slabp + 1);
}
-static void cache_init_objs(kmem_cache_t *cachep,
- struct slab *slabp, unsigned long ctor_flags)
+static void cache_init_objs(kmem_cache_t *cachep, struct slab *slabp,
+ unsigned long ctor_flags)
{
int i;
for (i = 0; i < cachep->num; i++) {
- void *objp = slabp->s_mem+cachep->objsize*i;
+ void *objp = slabp->s_mem + cachep->objsize * i;
#if DEBUG
/* need to poison the objs? */
if (cachep->flags & SLAB_POISON)
@@ -2096,7 +2112,8 @@ static void cache_init_objs(kmem_cache_t
* Otherwise, deadlock. They must also be threaded.
*/
if (cachep->ctor && !(cachep->flags & SLAB_POISON))
- cachep->ctor(objp+obj_dbghead(cachep), cachep, ctor_flags);
+ cachep->ctor(objp + obj_dbghead(cachep), cachep,
+ ctor_flags);
if (cachep->flags & SLAB_RED_ZONE) {
if (*dbg_redzone2(cachep, objp) != RED_INACTIVE)
@@ -2106,15 +2123,17 @@ static void cache_init_objs(kmem_cache_t
slab_error(cachep, "constructor overwrote the"
" start of an object");
}
- if ((cachep->objsize % PAGE_SIZE) == 0 && OFF_SLAB(cachep) && cachep->flags & SLAB_POISON)
- kernel_map_pages(virt_to_page(objp), cachep->objsize/PAGE_SIZE, 0);
+ if ((cachep->objsize % PAGE_SIZE) == 0 && OFF_SLAB(cachep) &&
+ cachep->flags & SLAB_POISON)
+ kernel_map_pages(virt_to_page(objp),
+ cachep->objsize / PAGE_SIZE, 0);
#else
if (cachep->ctor)
cachep->ctor(objp, cachep, ctor_flags);
#endif
- slab_bufctl(slabp)[i] = i+1;
+ slab_bufctl(slabp)[i] = i + 1;
}
- slab_bufctl(slabp)[i-1] = BUFCTL_END;
+ slab_bufctl(slabp)[i - 1] = BUFCTL_END;
slabp->free = 0;
}
@@ -2134,31 +2153,31 @@ static void set_slab_attr(kmem_cache_t *
int i;
struct page *page;
- /* Nasty!!!!!! I hope this is OK. */
i = 1 << cachep->gfporder;
page = virt_to_page(objp);
- do {
+ while (i--) {
SET_PAGE_CACHE(page, cachep);
SET_PAGE_SLAB(page, slabp);
page++;
- } while (--i);
+ }
}
/*
* Grow (by 1) the number of slabs within a cache. This is called by
* kmem_cache_alloc() when there are no active objs left in a cache.
*/
-static int cache_grow(kmem_cache_t *cachep, gfp_t flags, int nodeid)
+static int cache_grow(kmem_cache_t *cachep, gfp_t flags, int nid)
{
- struct slab *slabp;
- void *objp;
- size_t offset;
- gfp_t local_flags;
- unsigned long ctor_flags;
+ struct slab *slabp;
+ void *objp;
+ size_t offset;
+ gfp_t local_flags;
+ unsigned long ctor_flags;
struct kmem_list3 *l3;
- /* Be lazy and only check for valid flags here,
- * keeping it out of the critical path in kmem_cache_alloc().
+ /*
+ * Be lazy and only check for valid flags here,
+ * keeping it out of the critical path in kmem_cache_alloc().
*/
if (flags & ~(SLAB_DMA|SLAB_LEVEL_MASK|SLAB_NO_GROW))
BUG();
@@ -2192,24 +2211,22 @@ static int cache_grow(kmem_cache_t *cach
local_irq_enable();
/*
- * The test for missing atomic flag is performed here, rather than
- * the more obvious place, simply to reduce the critical path length
- * in kmem_cache_alloc(). If a caller is seriously mis-behaving they
- * will eventually be caught here (where it matters).
+ * Ensure caller isn't asking for DMA memory if the slab wasn't created
+ * with the SLAB_DMA flag.
+ * Also ensure the caller *is* asking for DMA memory if the slab was
+ * created with the SLAB_DMA flag.
*/
kmem_flagcheck(cachep, flags);
- /* Get mem for the objs.
- * Attempt to allocate a physical page from 'nodeid',
- */
- if (!(objp = kmem_getpages(cachep, flags, nodeid)))
- goto failed;
+ /* Get mem for the objects by allocating a physical page from 'nid' */
+ if (!(objp = kmem_getpages(cachep, flags, nid)))
+ goto out_nomem;
/* Get slab management. */
if (!(slabp = alloc_slabmgmt(cachep, objp, offset, local_flags)))
- goto opps1;
+ goto out_freepages;
- slabp->nodeid = nodeid;
+ slabp->nid = nid;
set_slab_attr(cachep, slabp, objp);
cache_init_objs(cachep, slabp, ctor_flags);
@@ -2217,7 +2234,7 @@ static int cache_grow(kmem_cache_t *cach
if (local_flags & __GFP_WAIT)
local_irq_disable();
check_irq_off();
- l3 = cachep->nodelists[nodeid];
+ l3 = cachep->nodelists[nid];
spin_lock(&l3->list_lock);
/* Make slab active. */
@@ -2226,16 +2243,15 @@ static int cache_grow(kmem_cache_t *cach
l3->free_objects += cachep->num;
spin_unlock(&l3->list_lock);
return 1;
-opps1:
+out_freepages:
kmem_freepages(cachep, objp);
-failed:
+out_nomem:
if (local_flags & __GFP_WAIT)
local_irq_disable();
return 0;
}
#if DEBUG
-
/*
* Perform extra freeing checks:
* - detect bad pointers.
@@ -2248,18 +2264,19 @@ static void kfree_debugcheck(const void
if (!virt_addr_valid(objp)) {
printk(KERN_ERR "kfree_debugcheck: out of range ptr %lxh.\n",
- (unsigned long)objp);
- BUG();
+ (unsigned long)objp);
+ BUG();
}
page = virt_to_page(objp);
if (!PageSlab(page)) {
- printk(KERN_ERR "kfree_debugcheck: bad ptr %lxh.\n", (unsigned long)objp);
+ printk(KERN_ERR "kfree_debugcheck: bad ptr %lxh.\n",
+ (unsigned long)objp);
BUG();
}
}
static void *cache_free_debugcheck(kmem_cache_t *cachep, void *objp,
- void *caller)
+ void *caller)
{
struct page *page;
unsigned int objnr;
@@ -2270,20 +2287,25 @@ static void *cache_free_debugcheck(kmem_
page = virt_to_page(objp);
if (GET_PAGE_CACHE(page) != cachep) {
- printk(KERN_ERR "mismatch in kmem_cache_free: expected cache %p, got %p\n",
- GET_PAGE_CACHE(page),cachep);
+ printk(KERN_ERR "mismatch in kmem_cache_free: "
+ "expected cache %p, got %p\n",
+ GET_PAGE_CACHE(page), cachep);
printk(KERN_ERR "%p is %s.\n", cachep, cachep->name);
- printk(KERN_ERR "%p is %s.\n", GET_PAGE_CACHE(page), GET_PAGE_CACHE(page)->name);
+ printk(KERN_ERR "%p is %s.\n", GET_PAGE_CACHE(page),
+ GET_PAGE_CACHE(page)->name);
WARN_ON(1);
}
slabp = GET_PAGE_SLAB(page);
if (cachep->flags & SLAB_RED_ZONE) {
- if (*dbg_redzone1(cachep, objp) != RED_ACTIVE || *dbg_redzone2(cachep, objp) != RED_ACTIVE) {
+ if (*dbg_redzone1(cachep, objp) != RED_ACTIVE ||
+ *dbg_redzone2(cachep, objp) != RED_ACTIVE) {
slab_error(cachep, "double free, or memory outside"
- " object was overwritten");
- printk(KERN_ERR "%p: redzone 1: 0x%lx, redzone 2: 0x%lx.\n",
- objp, *dbg_redzone1(cachep, objp), *dbg_redzone2(cachep, objp));
+ " object was overwritten");
+ printk(KERN_ERR "%p: redzone 1: 0x%lx, "
+ "redzone 2: 0x%lx.\n", objp,
+ *dbg_redzone1(cachep, objp),
+ *dbg_redzone2(cachep, objp));
}
*dbg_redzone1(cachep, objp) = RED_INACTIVE;
*dbg_redzone2(cachep, objp) = RED_INACTIVE;
@@ -2294,27 +2316,30 @@ static void *cache_free_debugcheck(kmem_
objnr = (objp-slabp->s_mem)/cachep->objsize;
BUG_ON(objnr >= cachep->num);
- BUG_ON(objp != slabp->s_mem + objnr*cachep->objsize);
+ BUG_ON(objp != slabp->s_mem + objnr * cachep->objsize);
if (cachep->flags & SLAB_DEBUG_INITIAL) {
- /* Need to call the slab's constructor so the
+ /*
+ * Need to call the slab's constructor so the
* caller can perform a verify of its state (debugging).
* Called without the cache-lock held.
*/
- cachep->ctor(objp+obj_dbghead(cachep),
- cachep, SLAB_CTOR_CONSTRUCTOR|SLAB_CTOR_VERIFY);
+ cachep->ctor(objp + obj_dbghead(cachep), cachep,
+ SLAB_CTOR_CONSTRUCTOR|SLAB_CTOR_VERIFY);
}
if (cachep->flags & SLAB_POISON && cachep->dtor) {
- /* we want to cache poison the object,
+ /*
+ * we want to cache poison the object,
* call the destruction callback
*/
- cachep->dtor(objp+obj_dbghead(cachep), cachep, 0);
+ cachep->dtor(objp + obj_dbghead(cachep), cachep, 0);
}
if (cachep->flags & SLAB_POISON) {
#ifdef CONFIG_DEBUG_PAGEALLOC
if ((cachep->objsize % PAGE_SIZE) == 0 && OFF_SLAB(cachep)) {
store_stackinfo(cachep, objp, (unsigned long)caller);
- kernel_map_pages(virt_to_page(objp), cachep->objsize/PAGE_SIZE, 0);
+ kernel_map_pages(virt_to_page(objp),
+ cachep->objsize / PAGE_SIZE, 0);
} else {
poison_obj(cachep, objp, POISON_FREE);
}
@@ -2338,10 +2363,13 @@ static void check_slabp(kmem_cache_t *ca
}
if (entries != cachep->num - slabp->inuse) {
bad:
- printk(KERN_ERR "slab: Internal list corruption detected in cache '%s'(%d), slabp %p(%d). Hexdump:\n",
- cachep->name, cachep->num, slabp, slabp->inuse);
- for (i=0;i<sizeof(slabp)+cachep->num*sizeof(kmem_bufctl_t);i++) {
- if ((i%16)==0)
+ printk(KERN_ERR "slab: Internal list corruption detected in "
+ "cache '%s'(%d), slabp %p(%d). Hexdump:\n",
+ cachep->name, cachep->num, slabp, slabp->inuse);
+ for (i = 0;
+ i < sizeof(slabp) + cachep->num * sizeof(kmem_bufctl_t);
+ i++) {
+ if ((i % 16) == 0)
printk("\n%03x:", i);
printk(" %02x", ((unsigned char*)slabp)[i]);
}
@@ -2350,9 +2378,9 @@ bad:
}
}
#else
-#define kfree_debugcheck(x) do { } while(0)
-#define cache_free_debugcheck(x,objp,z) (objp)
-#define check_slabp(x,y) do { } while(0)
+#define kfree_debugcheck(x) do { } while(0)
+#define cache_free_debugcheck(x,objp,z) (objp)
+#define check_slabp(x,y) do { } while(0)
#endif
static void *cache_alloc_refill(kmem_cache_t *cachep, gfp_t flags)
@@ -2366,7 +2394,8 @@ static void *cache_alloc_refill(kmem_cac
retry:
batchcount = ac->batchcount;
if (!ac->touched && batchcount > BATCHREFILL_LIMIT) {
- /* if there was little recent activity on this
+ /*
+ * if there was little recent activity on this
* cache, then perform only a partial refill.
* Otherwise we could generate refill bouncing.
*/
@@ -2385,8 +2414,8 @@ retry:
shared_array->avail -= batchcount;
ac->avail = batchcount;
memcpy(ac->entry,
- &(shared_array->entry[shared_array->avail]),
- sizeof(void*)*batchcount);
+ &(shared_array->entry[shared_array->avail]),
+ sizeof(void *) * batchcount);
shared_array->touched = 1;
goto alloc_done;
}
@@ -2420,9 +2449,9 @@ retry:
next = slab_bufctl(slabp)[slabp->free];
#if DEBUG
slab_bufctl(slabp)[slabp->free] = BUFCTL_FREE;
- WARN_ON(numa_node_id() != slabp->nodeid);
+ WARN_ON(numa_node_id() != slabp->nid);
#endif
- slabp->free = next;
+ slabp->free = next;
}
check_slabp(cachep, slabp);
@@ -2443,20 +2472,20 @@ alloc_done:
int x;
x = cache_grow(cachep, flags, numa_node_id());
- // cache_grow can reenable interrupts, then ac could change.
+ /* cache_grow can reenable interrupts, then ac could change. */
ac = ac_data(cachep);
- if (!x && ac->avail == 0) // no objects in sight? abort
+ if (!x && ac->avail == 0) /* no objects in sight? abort */
return NULL;
- if (!ac->avail) // objects refilled by interrupt?
+ if (!ac->avail) /* objects refilled by interrupt? */
goto retry;
}
ac->touched = 1;
return ac->entry[--ac->avail];
}
-static inline void
-cache_alloc_debugcheck_before(kmem_cache_t *cachep, gfp_t flags)
+static inline void cache_alloc_debugcheck_before(kmem_cache_t *cachep,
+ gfp_t flags)
{
might_sleep_if(flags & __GFP_WAIT);
#if DEBUG
@@ -2465,16 +2494,16 @@ cache_alloc_debugcheck_before(kmem_cache
}
#if DEBUG
-static void *
-cache_alloc_debugcheck_after(kmem_cache_t *cachep,
- gfp_t flags, void *objp, void *caller)
+static void *cache_alloc_debugcheck_after(kmem_cache_t *cachep, gfp_t flags,
+ void *objp, void *caller)
{
- if (!objp)
+ if (!objp)
return objp;
- if (cachep->flags & SLAB_POISON) {
+ if (cachep->flags & SLAB_POISON) {
#ifdef CONFIG_DEBUG_PAGEALLOC
if ((cachep->objsize % PAGE_SIZE) == 0 && OFF_SLAB(cachep))
- kernel_map_pages(virt_to_page(objp), cachep->objsize/PAGE_SIZE, 1);
+ kernel_map_pages(virt_to_page(objp),
+ cachep->objsize / PAGE_SIZE, 1);
else
check_poison_obj(cachep, objp);
#else
@@ -2486,24 +2515,27 @@ cache_alloc_debugcheck_after(kmem_cache_
*dbg_userword(cachep, objp) = caller;
if (cachep->flags & SLAB_RED_ZONE) {
- if (*dbg_redzone1(cachep, objp) != RED_INACTIVE || *dbg_redzone2(cachep, objp) != RED_INACTIVE) {
- slab_error(cachep, "double free, or memory outside"
- " object was overwritten");
- printk(KERN_ERR "%p: redzone 1: 0x%lx, redzone 2: 0x%lx.\n",
- objp, *dbg_redzone1(cachep, objp), *dbg_redzone2(cachep, objp));
+ if (*dbg_redzone1(cachep, objp) != RED_INACTIVE ||
+ *dbg_redzone2(cachep, objp) != RED_INACTIVE) {
+ slab_error(cachep, "double free, or memory outside "
+ "object was overwritten");
+ printk(KERN_ERR "%p: redzone 1: 0x%lx, "
+ "redzone 2: 0x%lx.\n", objp,
+ *dbg_redzone1(cachep, objp),
+ *dbg_redzone2(cachep, objp));
}
*dbg_redzone1(cachep, objp) = RED_ACTIVE;
*dbg_redzone2(cachep, objp) = RED_ACTIVE;
}
objp += obj_dbghead(cachep);
if (cachep->ctor && cachep->flags & SLAB_POISON) {
- unsigned long ctor_flags = SLAB_CTOR_CONSTRUCTOR;
+ unsigned long ctor_flags = SLAB_CTOR_CONSTRUCTOR;
if (!(flags & __GFP_WAIT))
ctor_flags |= SLAB_CTOR_ATOMIC;
cachep->ctor(objp, cachep, ctor_flags);
- }
+ }
return objp;
}
#else
@@ -2531,7 +2563,7 @@ static inline void *____cache_alloc(kmem
static inline void *__cache_alloc(kmem_cache_t *cachep, gfp_t flags)
{
unsigned long save_flags;
- void* objp;
+ void *objp;
cache_alloc_debugcheck_before(cachep, flags);
@@ -2539,86 +2571,87 @@ static inline void *__cache_alloc(kmem_c
objp = ____cache_alloc(cachep, flags);
local_irq_restore(save_flags);
objp = cache_alloc_debugcheck_after(cachep, flags, objp,
- __builtin_return_address(0));
+ __builtin_return_address(0));
prefetchw(objp);
return objp;
}
#ifdef CONFIG_NUMA
/*
- * A interface to enable slab creation on nodeid
+ * A interface to enable slab creation on nid
*/
-static void *__cache_alloc_node(kmem_cache_t *cachep, gfp_t flags, int nodeid)
+static void *__cache_alloc_node(kmem_cache_t *cachep, gfp_t flags, int nid)
{
struct list_head *entry;
- struct slab *slabp;
- struct kmem_list3 *l3;
- void *obj;
- kmem_bufctl_t next;
- int x;
+ struct slab *slabp;
+ struct kmem_list3 *l3;
+ void *obj;
+ kmem_bufctl_t next;
+ int x;
- l3 = cachep->nodelists[nodeid];
- BUG_ON(!l3);
+ l3 = cachep->nodelists[nid];
+ BUG_ON(!l3);
retry:
- spin_lock(&l3->list_lock);
- entry = l3->slabs_partial.next;
- if (entry == &l3->slabs_partial) {
- l3->free_touched = 1;
- entry = l3->slabs_free.next;
- if (entry == &l3->slabs_free)
- goto must_grow;
- }
-
- slabp = list_entry(entry, struct slab, list);
- check_spinlock_acquired_node(cachep, nodeid);
- check_slabp(cachep, slabp);
-
- STATS_INC_NODEALLOCS(cachep);
- STATS_INC_ACTIVE(cachep);
- STATS_SET_HIGH(cachep);
-
- BUG_ON(slabp->inuse == cachep->num);
-
- /* get obj pointer */
- obj = slabp->s_mem + slabp->free*cachep->objsize;
- slabp->inuse++;
- next = slab_bufctl(slabp)[slabp->free];
-#if DEBUG
- slab_bufctl(slabp)[slabp->free] = BUFCTL_FREE;
-#endif
- slabp->free = next;
- check_slabp(cachep, slabp);
- l3->free_objects--;
- /* move slabp to correct slabp list: */
- list_del(&slabp->list);
-
- if (slabp->free == BUFCTL_END) {
- list_add(&slabp->list, &l3->slabs_full);
- } else {
- list_add(&slabp->list, &l3->slabs_partial);
- }
+ spin_lock(&l3->list_lock);
+ entry = l3->slabs_partial.next;
+ if (entry == &l3->slabs_partial) {
+ l3->free_touched = 1;
+ entry = l3->slabs_free.next;
+ if (entry == &l3->slabs_free)
+ goto must_grow;
+ }
+
+ slabp = list_entry(entry, struct slab, list);
+ check_spinlock_acquired_node(cachep, nid);
+ check_slabp(cachep, slabp);
+
+ STATS_INC_NODEALLOCS(cachep);
+ STATS_INC_ACTIVE(cachep);
+ STATS_SET_HIGH(cachep);
+
+ BUG_ON(slabp->inuse == cachep->num);
+
+ /* get obj pointer */
+ obj = slabp->s_mem + slabp->free * cachep->objsize;
+ slabp->inuse++;
+ next = slab_bufctl(slabp)[slabp->free];
+#if DEBUG
+ slab_bufctl(slabp)[slabp->free] = BUFCTL_FREE;
+#endif
+ slabp->free = next;
+ check_slabp(cachep, slabp);
+ l3->free_objects--;
+ /* move slabp to correct slabp list: */
+ list_del(&slabp->list);
+
+ if (slabp->free == BUFCTL_END) {
+ list_add(&slabp->list, &l3->slabs_full);
+ } else {
+ list_add(&slabp->list, &l3->slabs_partial);
+ }
- spin_unlock(&l3->list_lock);
- goto done;
+ spin_unlock(&l3->list_lock);
+ goto done;
must_grow:
- spin_unlock(&l3->list_lock);
- x = cache_grow(cachep, flags, nodeid);
+ spin_unlock(&l3->list_lock);
+ x = cache_grow(cachep, flags, nid);
- if (!x)
- return NULL;
+ if (!x)
+ return NULL;
- goto retry;
+ goto retry;
done:
- return obj;
+ return obj;
}
#endif
/*
* Caller needs to acquire correct kmem_list's list_lock
*/
-static void free_block(kmem_cache_t *cachep, void **objpp, int nr_objects, int node)
+static void free_block(kmem_cache_t *cachep, void **objpp, int nr_objects,
+ int nid)
{
int i;
struct kmem_list3 *l3;
@@ -2629,15 +2662,15 @@ static void free_block(kmem_cache_t *cac
unsigned int objnr;
slabp = GET_PAGE_SLAB(virt_to_page(objp));
- l3 = cachep->nodelists[node];
+ l3 = cachep->nodelists[nid];
list_del(&slabp->list);
objnr = (objp - slabp->s_mem) / cachep->objsize;
- check_spinlock_acquired_node(cachep, node);
+ check_spinlock_acquired_node(cachep, nid);
check_slabp(cachep, slabp);
#if DEBUG
/* Verify that the slab belongs to the intended node */
- WARN_ON(slabp->nodeid != node);
+ WARN_ON(slabp->nid != nid);
if (slab_bufctl(slabp)[objnr] != BUFCTL_FREE) {
printk(KERN_ERR "slab: double free detected in cache "
@@ -2661,7 +2694,8 @@ static void free_block(kmem_cache_t *cac
list_add(&slabp->list, &l3->slabs_free);
}
} else {
- /* Unconditionally move a slab to the end of the
+ /*
+ * Unconditionally move a slab to the end of the
* partial list on free - maximum time for the
* other objects to be freed, too.
*/
@@ -2674,30 +2708,29 @@ static void cache_flusharray(kmem_cache_
{
int batchcount;
struct kmem_list3 *l3;
- int node = numa_node_id();
+ int nid = numa_node_id();
batchcount = ac->batchcount;
#if DEBUG
BUG_ON(!batchcount || batchcount > ac->avail);
#endif
check_irq_off();
- l3 = cachep->nodelists[node];
+ l3 = cachep->nodelists[nid];
spin_lock(&l3->list_lock);
if (l3->shared) {
struct array_cache *shared_array = l3->shared;
- int max = shared_array->limit-shared_array->avail;
+ int max = shared_array->limit - shared_array->avail;
if (max) {
if (batchcount > max)
batchcount = max;
memcpy(&(shared_array->entry[shared_array->avail]),
- ac->entry,
- sizeof(void*)*batchcount);
+ ac->entry, sizeof(void *) * batchcount);
shared_array->avail += batchcount;
goto free_done;
}
}
- free_block(cachep, ac->entry, batchcount, node);
+ free_block(cachep, ac->entry, batchcount, nid);
free_done:
#if STATS
{
@@ -2720,11 +2753,11 @@ free_done:
spin_unlock(&l3->list_lock);
ac->avail -= batchcount;
memmove(ac->entry, &(ac->entry[batchcount]),
- sizeof(void*)*ac->avail);
+ sizeof(void *) * ac->avail);
}
-/*
+/**
* __cache_free
* Release an obj back to its cache. If the obj has a constructed
* state, it must be in this state _before_ it is released.
@@ -2738,33 +2771,32 @@ static inline void __cache_free(kmem_cac
check_irq_off();
objp = cache_free_debugcheck(cachep, objp, __builtin_return_address(0));
- /* Make sure we are not freeing a object from another
+ /*
+ * Make sure we are not freeing a object from another
* node to the array cache on this cpu.
*/
#ifdef CONFIG_NUMA
{
struct slab *slabp;
slabp = GET_PAGE_SLAB(virt_to_page(objp));
- if (unlikely(slabp->nodeid != numa_node_id())) {
+ if (unlikely(slabp->nid != numa_node_id())) {
struct array_cache *alien = NULL;
- int nodeid = slabp->nodeid;
- struct kmem_list3 *l3 = cachep->nodelists[numa_node_id()];
+ int nid = slabp->nid;
+ struct kmem_list3 *l3 =
+ cachep->nodelists[numa_node_id()];
STATS_INC_NODEFREES(cachep);
- if (l3->alien && l3->alien[nodeid]) {
- alien = l3->alien[nodeid];
+ if (l3->alien && l3->alien[nid]) {
+ alien = l3->alien[nid];
spin_lock(&alien->lock);
if (unlikely(alien->avail == alien->limit))
- __drain_alien_cache(cachep,
- alien, nodeid);
+ __drain_alien_cache(cachep, alien, nid);
alien->entry[alien->avail++] = objp;
spin_unlock(&alien->lock);
} else {
- spin_lock(&(cachep->nodelists[nodeid])->
- list_lock);
- free_block(cachep, &objp, 1, nodeid);
- spin_unlock(&(cachep->nodelists[nodeid])->
- list_lock);
+ spin_lock(&(cachep->nodelists[nid])->list_lock);
+ free_block(cachep, &objp, 1, nid);
+ spin_unlock(&(cachep->nodelists[nid])->list_lock);
}
return;
}
@@ -2796,8 +2828,7 @@ void *kmem_cache_alloc(kmem_cache_t *cac
EXPORT_SYMBOL(kmem_cache_alloc);
/**
- * kmem_ptr_validate - check if an untrusted pointer might
- * be a slab entry.
+ * kmem_ptr_validate - check if an untrusted pointer might be a slab entry.
* @cachep: the cache we're checking against
* @ptr: pointer to validate
*
@@ -2811,7 +2842,7 @@ EXPORT_SYMBOL(kmem_cache_alloc);
*/
int fastcall kmem_ptr_validate(kmem_cache_t *cachep, void *ptr)
{
- unsigned long addr = (unsigned long) ptr;
+ unsigned long addr = (unsigned long)ptr;
unsigned long min_addr = PAGE_OFFSET;
unsigned long align_mask = BYTES_PER_WORD-1;
unsigned long size = cachep->objsize;
@@ -2842,7 +2873,7 @@ out:
* kmem_cache_alloc_node - Allocate an object on the specified node
* @cachep: The cache to allocate from.
* @flags: See kmalloc().
- * @nodeid: node number of the target node.
+ * @nid: node number of the target node.
*
* Identical to kmem_cache_alloc, except that this function is slow
* and can sleep. And it will allocate memory on the given node, which
@@ -2850,41 +2881,43 @@ out:
* New and improved: it will now make sure that the object gets
* put on the correct node list so that there is no false sharing.
*/
-void *kmem_cache_alloc_node(kmem_cache_t *cachep, gfp_t flags, int nodeid)
+void *kmem_cache_alloc_node(kmem_cache_t *cachep, gfp_t flags, int nid)
{
unsigned long save_flags;
void *ptr;
- if (nodeid == -1)
+ if (nid == -1)
return __cache_alloc(cachep, flags);
- if (unlikely(!cachep->nodelists[nodeid])) {
+ if (unlikely(!cachep->nodelists[nid])) {
/* Fall back to __cache_alloc if we run into trouble */
- printk(KERN_WARNING "slab: not allocating in inactive node %d for cache %s\n", nodeid, cachep->name);
+ printk(KERN_WARNING "slab: not allocating in inactive node %d "
+ "for cache %s\n", nid, cachep->name);
return __cache_alloc(cachep,flags);
}
cache_alloc_debugcheck_before(cachep, flags);
local_irq_save(save_flags);
- if (nodeid == numa_node_id())
+ if (nid == numa_node_id())
ptr = ____cache_alloc(cachep, flags);
else
- ptr = __cache_alloc_node(cachep, flags, nodeid);
+ ptr = __cache_alloc_node(cachep, flags, nid);
local_irq_restore(save_flags);
- ptr = cache_alloc_debugcheck_after(cachep, flags, ptr, __builtin_return_address(0));
+ ptr = cache_alloc_debugcheck_after(cachep, flags, ptr,
+ __builtin_return_address(0));
return ptr;
}
EXPORT_SYMBOL(kmem_cache_alloc_node);
-void *kmalloc_node(size_t size, gfp_t flags, int node)
+void *kmalloc_node(size_t size, gfp_t flags, int nid)
{
kmem_cache_t *cachep;
cachep = kmem_find_general_cachep(size, flags);
if (unlikely(cachep == NULL))
return NULL;
- return kmem_cache_alloc_node(cachep, flags, node);
+ return kmem_cache_alloc_node(cachep, flags, nid);
}
EXPORT_SYMBOL(kmalloc_node);
#endif
@@ -2914,10 +2947,9 @@ void *__kmalloc(size_t size, gfp_t flags
{
kmem_cache_t *cachep;
- /* If you want to save a few bytes .text space: replace
- * __ with kmem_.
- * Then kmalloc uses the uninlined functions instead of the inline
- * functions.
+ /*
+ * If you want to save a few bytes .text space: replace __ with kmem_
+ * Then kmalloc uses the uninlined functions vs. the inline functions
*/
cachep = __find_general_cachep(size, flags);
if (unlikely(cachep == NULL))
@@ -2933,12 +2965,11 @@ EXPORT_SYMBOL(__kmalloc);
* Objects should be dereferenced using the per_cpu_ptr macro only.
*
* @size: how many bytes of memory are required.
- * @align: the alignment, which can't be greater than SMP_CACHE_BYTES.
*/
-void *__alloc_percpu(size_t size, size_t align)
+void *__alloc_percpu(size_t size)
{
int i;
- struct percpu_data *pdata = kmalloc(sizeof (*pdata), GFP_KERNEL);
+ struct percpu_data *pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);
if (!pdata)
return NULL;
@@ -2949,10 +2980,10 @@ void *__alloc_percpu(size_t size, size_t
* that we have allocated then....
*/
for_each_cpu(i) {
- int node = cpu_to_node(i);
+ int nid = cpu_to_node(i);
- if (node_online(node))
- pdata->ptrs[i] = kmalloc_node(size, GFP_KERNEL, node);
+ if (node_online(nid))
+ pdata->ptrs[i] = kmalloc_node(size, GFP_KERNEL, nid);
else
pdata->ptrs[i] = kmalloc(size, GFP_KERNEL);
@@ -2962,14 +2993,11 @@ void *__alloc_percpu(size_t size, size_t
}
/* Catch derefs w/o wrappers */
- return (void *) (~(unsigned long) pdata);
+ return (void *)(~(unsigned long) pdata);
unwind_oom:
- while (--i >= 0) {
- if (!cpu_possible(i))
- continue;
+ while (--i >= 0)
kfree(pdata->ptrs[i]);
- }
kfree(pdata);
return NULL;
}
@@ -3027,7 +3055,7 @@ void kfree(const void *objp)
local_irq_save(flags);
kfree_debugcheck(objp);
c = GET_PAGE_CACHE(virt_to_page(objp));
- __cache_free(c, (void*)objp);
+ __cache_free(c, (void *)objp);
local_irq_restore(flags);
}
EXPORT_SYMBOL(kfree);
@@ -3040,11 +3068,10 @@ EXPORT_SYMBOL(kfree);
* Don't free memory not originally allocated by alloc_percpu()
* The complemented objp is to check for that.
*/
-void
-free_percpu(const void *objp)
+void free_percpu(const void *objp)
{
int i;
- struct percpu_data *p = (struct percpu_data *) (~(unsigned long) objp);
+ struct percpu_data *p = (struct percpu_data *)(~(unsigned long)objp);
/*
* We allocate for all cpus so we cannot use for online cpu here.
@@ -3073,52 +3100,50 @@ EXPORT_SYMBOL_GPL(kmem_cache_name);
*/
static int alloc_kmemlist(kmem_cache_t *cachep)
{
- int node;
+ int nid;
struct kmem_list3 *l3;
int err = 0;
- for_each_online_node(node) {
+ for_each_online_node(nid) {
struct array_cache *nc = NULL, *new;
struct array_cache **new_alien = NULL;
#ifdef CONFIG_NUMA
- if (!(new_alien = alloc_alien_cache(node, cachep->limit)))
+ if (!(new_alien = alloc_alien_cache(nid, cachep->limit)))
goto fail;
#endif
- if (!(new = alloc_arraycache(node, (cachep->shared*
- cachep->batchcount), 0xbaadf00d)))
+ if (!(new = alloc_arraycache(nid, cachep->shared *
+ cachep->batchcount, 0xbaadf00d)))
goto fail;
- if ((l3 = cachep->nodelists[node])) {
-
+ if ((l3 = cachep->nodelists[nid])) {
spin_lock_irq(&l3->list_lock);
- if ((nc = cachep->nodelists[node]->shared))
- free_block(cachep, nc->entry,
- nc->avail, node);
+ if ((nc = cachep->nodelists[nid]->shared))
+ free_block(cachep, nc->entry, nc->avail, nid);
l3->shared = new;
- if (!cachep->nodelists[node]->alien) {
+ if (!cachep->nodelists[nid]->alien) {
l3->alien = new_alien;
new_alien = NULL;
}
- l3->free_limit = (1 + nr_cpus_node(node))*
- cachep->batchcount + cachep->num;
+ l3->free_limit = cachep->num +
+ (1 + nr_cpus_node(nid)) * cachep->batchcount;
spin_unlock_irq(&l3->list_lock);
kfree(nc);
free_alien_cache(new_alien);
continue;
}
if (!(l3 = kmalloc_node(sizeof(struct kmem_list3),
- GFP_KERNEL, node)))
+ GFP_KERNEL, nid)))
goto fail;
kmem_list3_init(l3);
l3->next_reap = jiffies + REAPTIMEOUT_LIST3 +
- ((unsigned long)cachep)%REAPTIMEOUT_LIST3;
+ ((unsigned long)cachep) % REAPTIMEOUT_LIST3;
l3->shared = new;
l3->alien = new_alien;
- l3->free_limit = (1 + nr_cpus_node(node))*
- cachep->batchcount + cachep->num;
- cachep->nodelists[node] = l3;
+ l3->free_limit = cachep->num +
+ (1 + nr_cpus_node(nid)) * cachep->batchcount;
+ cachep->nodelists[nid] = l3;
}
return err;
fail:
@@ -3145,16 +3170,18 @@ static void do_ccupdate_local(void *info
static int do_tune_cpucache(kmem_cache_t *cachep, int limit, int batchcount,
- int shared)
+ int shared)
{
struct ccupdate_struct new;
int i, err;
- memset(&new.new,0,sizeof(new.new));
+ memset(&new.new, 0, sizeof(new.new));
for_each_online_cpu(i) {
- new.new[i] = alloc_arraycache(cpu_to_node(i), limit, batchcount);
+ new.new[i] = alloc_arraycache(cpu_to_node(i), limit,
+ batchcount);
if (!new.new[i]) {
- for (i--; i >= 0; i--) kfree(new.new[i]);
+ for (i--; i >= 0; i--)
+ kfree(new.new[i]);
return -ENOMEM;
}
}
@@ -3182,7 +3209,7 @@ static int do_tune_cpucache(kmem_cache_t
err = alloc_kmemlist(cachep);
if (err) {
printk(KERN_ERR "alloc_kmemlist failed for %s, error %d.\n",
- cachep->name, -err);
+ cachep->name, -err);
BUG();
}
return 0;
@@ -3194,10 +3221,11 @@ static void enable_cpucache(kmem_cache_t
int err;
int limit, shared;
- /* The head array serves three purposes:
+ /*
+ * The head array serves three purposes:
* - create a LIFO ordering, i.e. return objects that are cache-warm
* - reduce the number of spinlock operations.
- * - reduce the number of linked list operations on the slab and
+ * - reduce the number of linked list operations on the slab and
* bufctl chains: array operations are cheaper.
* The numbers are guessed, we should auto-tune as described by
* Bonwick.
@@ -3213,7 +3241,8 @@ static void enable_cpucache(kmem_cache_t
else
limit = 120;
- /* Cpu bound tasks (e.g. network routing) can exhibit cpu bound
+ /*
+ * Cpu bound tasks (e.g. network routing) can exhibit cpu bound
* allocation behaviour: Most allocs on one cpu, most free operations
* on another cpu. For these cases, an efficient object passing between
* cpus is necessary. This is provided by a shared array. The array
@@ -3228,36 +3257,37 @@ static void enable_cpucache(kmem_cache_t
#endif
#if DEBUG
- /* With debugging enabled, large batchcount lead to excessively
- * long periods with disabled local interrupts. Limit the
+ /*
+ * With debugging enabled, large batchcount lead to excessively
+ * long periods with disabled local interrupts. Limit the
* batchcount
*/
if (limit > 32)
limit = 32;
#endif
- err = do_tune_cpucache(cachep, limit, (limit+1)/2, shared);
+ err = do_tune_cpucache(cachep, limit, (limit + 1) / 2, shared);
if (err)
printk(KERN_ERR "enable_cpucache failed for %s, error %d.\n",
- cachep->name, -err);
+ cachep->name, -err);
}
-static void drain_array_locked(kmem_cache_t *cachep,
- struct array_cache *ac, int force, int node)
+static void drain_array_locked(kmem_cache_t *cachep, struct array_cache *ac,
+ int force, int nid)
{
int tofree;
- check_spinlock_acquired_node(cachep, node);
+ check_spinlock_acquired_node(cachep, nid);
if (ac->touched && !force) {
ac->touched = 0;
} else if (ac->avail) {
- tofree = force ? ac->avail : (ac->limit+4)/5;
+ tofree = force ? ac->avail : (ac->limit + 4) / 5;
if (tofree > ac->avail) {
- tofree = (ac->avail+1)/2;
+ tofree = (ac->avail + 1) / 2;
}
- free_block(cachep, ac->entry, tofree, node);
+ free_block(cachep, ac->entry, tofree, nid);
ac->avail -= tofree;
memmove(ac->entry, &(ac->entry[tofree]),
- sizeof(void*)*ac->avail);
+ sizeof(void *) * ac->avail);
}
}
@@ -3275,53 +3305,44 @@ static void drain_array_locked(kmem_cach
*/
static void cache_reap(void *unused)
{
- struct list_head *walk;
- struct kmem_list3 *l3;
-
- if (down_trylock(&cache_chain_sem)) {
- /* Give up. Setup the next iteration. */
- schedule_delayed_work(&__get_cpu_var(reap_work), REAPTIMEOUT_CPUC);
- return;
- }
+ kmem_cache_t *searchp;
- list_for_each(walk, &cache_chain) {
- kmem_cache_t *searchp;
- struct list_head* p;
- int tofree;
- struct slab *slabp;
+ if (down_trylock(&cache_chain_sem))
+ goto out;
- searchp = list_entry(walk, kmem_cache_t, next);
+ list_for_each_entry(searchp, &cache_chain, next) {
+ struct kmem_list3 *l3;
+ int tofree, nid = numa_node_id();
if (searchp->flags & SLAB_NO_REAP)
goto next;
check_irq_on();
-
- l3 = searchp->nodelists[numa_node_id()];
+ l3 = searchp->nodelists[nid];
if (l3->alien)
drain_alien_cache(searchp, l3);
spin_lock_irq(&l3->list_lock);
- drain_array_locked(searchp, ac_data(searchp), 0,
- numa_node_id());
+ drain_array_locked(searchp, ac_data(searchp), 0, nid);
if (time_after(l3->next_reap, jiffies))
goto next_unlock;
-
l3->next_reap = jiffies + REAPTIMEOUT_LIST3;
if (l3->shared)
- drain_array_locked(searchp, l3->shared, 0,
- numa_node_id());
+ drain_array_locked(searchp, l3->shared, 0, nid);
if (l3->free_touched) {
l3->free_touched = 0;
goto next_unlock;
}
- tofree = (l3->free_limit+5*searchp->num-1)/(5*searchp->num);
+ tofree = 5 * searchp->num;
+ tofree = (l3->free_limit + tofree - 1) / tofree;
do {
- p = l3->slabs_free.next;
+ struct list_head *p = l3->slabs_free.next;
+ struct slab *slabp;
+
if (p == &(l3->slabs_free))
break;
@@ -3330,10 +3351,10 @@ static void cache_reap(void *unused)
list_del(&slabp->list);
STATS_INC_REAPED(searchp);
- /* Safe to drop the lock. The slab is no longer
- * linked to the cache.
- * searchp cannot disappear, we hold
- * cache_chain_lock
+ /*
+ * Safe to drop the lock:
+ * The slab is no longer linked to the cache
+ * searchp cannot disappear, we hold cache_chain_lock
*/
l3->free_objects -= searchp->num;
spin_unlock_irq(&l3->list_lock);
@@ -3348,38 +3369,44 @@ next:
check_irq_on();
up(&cache_chain_sem);
drain_remote_pages();
+out:
/* Setup the next iteration */
schedule_delayed_work(&__get_cpu_var(reap_work), REAPTIMEOUT_CPUC);
}
#ifdef CONFIG_PROC_FS
-static void *s_start(struct seq_file *m, loff_t *pos)
+static inline void print_slabinfo_header(struct seq_file *m)
{
- loff_t n = *pos;
- struct list_head *p;
-
- down(&cache_chain_sem);
- if (!n) {
- /*
- * Output format version, so at least we can change it
- * without _too_ many complaints.
- */
+ /*
+ * Output format version, so at least we can change it
+ * without _too_ many complaints.
+ */
#if STATS
- seq_puts(m, "slabinfo - version: 2.1 (statistics)\n");
+ seq_puts(m, "slabinfo - version: 2.1 (statistics)\n");
#else
- seq_puts(m, "slabinfo - version: 2.1\n");
+ seq_puts(m, "slabinfo - version: 2.1\n");
#endif
- seq_puts(m, "# name <active_objs> <num_objs> <objsize> <objperslab> <pagesperslab>");
- seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>");
- seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>");
+ seq_puts(m, "# name <active_objs> <num_objs> <objsize> "
+ "<objperslab> <pagesperslab>");
+ seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>");
+ seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>");
#if STATS
- seq_puts(m, " : globalstat <listallocs> <maxobjs> <grown> <reaped>"
- " <error> <maxfreeable> <nodeallocs> <remotefrees>");
- seq_puts(m, " : cpustat <allochit> <allocmiss> <freehit> <freemiss>");
+ seq_puts(m, " : globalstat <listallocs> <maxobjs> <grown> <reaped> "
+ "<error> <maxfreeable> <nodeallocs> <remotefrees>");
+ seq_puts(m, " : cpustat <allochit> <allocmiss> <freehit> <freemiss>");
#endif
- seq_putc(m, '\n');
- }
+ seq_putc(m, '\n');
+}
+
+static void *s_start(struct seq_file *m, loff_t *pos)
+{
+ loff_t n = *pos;
+ struct list_head *p;
+
+ down(&cache_chain_sem);
+ if (!n)
+ print_slabinfo_header(m);
p = cache_chain.next;
while (n--) {
p = p->next;
@@ -3393,8 +3420,8 @@ static void *s_next(struct seq_file *m,
{
kmem_cache_t *cachep = p;
++*pos;
- return cachep->next.next == &cache_chain ? NULL
- : list_entry(cachep->next.next, kmem_cache_t, next);
+ return cachep->next.next == &cache_chain ? NULL :
+ list_entry(cachep->next.next, kmem_cache_t, next);
}
static void s_stop(struct seq_file *m, void *p)
@@ -3406,22 +3433,20 @@ static int s_show(struct seq_file *m, vo
{
kmem_cache_t *cachep = p;
struct list_head *q;
- struct slab *slabp;
- unsigned long active_objs;
- unsigned long num_objs;
- unsigned long active_slabs = 0;
- unsigned long num_slabs, free_objects = 0, shared_avail = 0;
+ struct slab *slabp;
+ unsigned long active_objs, num_objs, active_slabs = 0;
+ unsigned long num_slabs, free_objects = 0, shared_avail = 0;
const char *name;
char *error = NULL;
- int node;
+ int nid;
struct kmem_list3 *l3;
check_irq_on();
spin_lock_irq(&cachep->spinlock);
active_objs = 0;
num_slabs = 0;
- for_each_online_node(node) {
- l3 = cachep->nodelists[node];
+ for_each_online_node(nid) {
+ l3 = cachep->nodelists[nid];
if (!l3)
continue;
@@ -3437,7 +3462,7 @@ static int s_show(struct seq_file *m, vo
list_for_each(q,&l3->slabs_partial) {
slabp = list_entry(q, struct slab, list);
if (slabp->inuse == cachep->num && !error)
- error = "slabs_partial inuse accounting error";
+ error = "slabs_partial/inuse accounting error";
if (!slabp->inuse && !error)
error = "slabs_partial/inuse accounting error";
active_objs += slabp->inuse;
@@ -3454,23 +3479,23 @@ static int s_show(struct seq_file *m, vo
spin_unlock(&l3->list_lock);
}
- num_slabs+=active_slabs;
- num_objs = num_slabs*cachep->num;
+ num_slabs += active_slabs;
+ num_objs = num_slabs * cachep->num;
if (num_objs - active_objs != free_objects && !error)
error = "free_objects accounting error";
- name = cachep->name;
+ name = cachep->name;
if (error)
printk(KERN_ERR "slab: cache %s error: %s\n", name, error);
- seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d",
- name, active_objs, num_objs, cachep->objsize,
- cachep->num, (1<<cachep->gfporder));
+ seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d", name, active_objs,
+ num_objs, cachep->objsize, cachep->num,
+ (1 << cachep->gfporder));
seq_printf(m, " : tunables %4u %4u %4u",
- cachep->limit, cachep->batchcount,
- cachep->shared);
+ cachep->limit, cachep->batchcount,
+ cachep->shared);
seq_printf(m, " : slabdata %6lu %6lu %6lu",
- active_slabs, num_slabs, shared_avail);
+ active_slabs, num_slabs, shared_avail);
#if STATS
{ /* list3 stats */
unsigned long high = cachep->high_mark;
@@ -3483,9 +3508,9 @@ static int s_show(struct seq_file *m, vo
unsigned long node_frees = cachep->node_frees;
seq_printf(m, " : globalstat %7lu %6lu %5lu %4lu \
- %4lu %4lu %4lu %4lu",
- allocs, high, grown, reaped, errors,
- max_freeable, node_allocs, node_frees);
+ %4lu %4lu %4lu %4lu", allocs, high, grown,
+ reaped, errors, max_freeable, node_allocs,
+ node_frees);
}
/* cpu stats */
{
@@ -3495,7 +3520,7 @@ static int s_show(struct seq_file *m, vo
unsigned long freemiss = atomic_read(&cachep->freemiss);
seq_printf(m, " : cpustat %6lu %6lu %6lu %6lu",
- allochit, allocmiss, freehit, freemiss);
+ allochit, allocmiss, freehit, freemiss);
}
#endif
seq_putc(m, '\n');
@@ -3516,7 +3541,6 @@ static int s_show(struct seq_file *m, vo
* num-pages-per-slab
* + further values on SMP and with statistics enabled
*/
-
struct seq_operations slabinfo_op = {
.start = s_start,
.next = s_next,
@@ -3533,17 +3557,17 @@ struct seq_operations slabinfo_op = {
* @ppos: unused
*/
ssize_t slabinfo_write(struct file *file, const char __user *buffer,
- size_t count, loff_t *ppos)
+ size_t count, loff_t *ppos)
{
char kbuf[MAX_SLABINFO_WRITE+1], *tmp;
int limit, batchcount, shared, res;
struct list_head *p;
-
+
if (count > MAX_SLABINFO_WRITE)
return -EINVAL;
if (copy_from_user(&kbuf, buffer, count))
return -EFAULT;
- kbuf[MAX_SLABINFO_WRITE] = '\0';
+ kbuf[MAX_SLABINFO_WRITE] = '\0';
tmp = strchr(kbuf, ' ');
if (!tmp)
@@ -3552,32 +3576,26 @@ ssize_t slabinfo_write(struct file *file
tmp++;
if (sscanf(tmp, " %d %d %d", &limit, &batchcount, &shared) != 3)
return -EINVAL;
+ if (limit < 1 || batchcount < 1 || batchcount > limit || shared < 0)
+ return 0;
/* Find the cache in the chain of caches. */
down(&cache_chain_sem);
res = -EINVAL;
list_for_each(p,&cache_chain) {
kmem_cache_t *cachep = list_entry(p, kmem_cache_t, next);
+ if (strcmp(cachep->name, kbuf))
+ continue;
- if (!strcmp(cachep->name, kbuf)) {
- if (limit < 1 ||
- batchcount < 1 ||
- batchcount > limit ||
- shared < 0) {
- res = 0;
- } else {
- res = do_tune_cpucache(cachep, limit,
- batchcount, shared);
- }
- break;
- }
+ res = do_tune_cpucache(cachep, limit, batchcount, shared);
+ if (res >= 0)
+ res = count;
+ break;
}
up(&cache_chain_sem);
- if (res >= 0)
- res = count;
return res;
}
-#endif
+#endif /* CONFIG_PROC_FS */
/**
* ksize - get the actual amount of memory allocated for a given object
@@ -3600,7 +3618,7 @@ unsigned int ksize(const void *objp)
}
-/*
+/**
* kstrdup - allocate space for and copy an existing string
*
* @s: the string to duplicate
Index: linux-2.6.15-rc1+slab_cleanup/net/ipv6/af_inet6.c
===================================================================
--- linux-2.6.15-rc1+slab_cleanup.orig/net/ipv6/af_inet6.c 2005-11-15 15:21:47.659921992 -0800
+++ linux-2.6.15-rc1+slab_cleanup/net/ipv6/af_inet6.c 2005-11-15 15:23:47.707671960 -0800
@@ -596,11 +596,11 @@ snmp6_mib_init(void *ptr[2], size_t mibs
if (ptr == NULL)
return -EINVAL;
- ptr[0] = __alloc_percpu(mibsize, mibalign);
+ ptr[0] = __alloc_percpu(mibsize);
if (!ptr[0])
goto err0;
- ptr[1] = __alloc_percpu(mibsize, mibalign);
+ ptr[1] = __alloc_percpu(mibsize);
if (!ptr[1])
goto err1;
^ permalink raw reply [flat|nested] 28+ messages in thread
* [RFC][PATCH 4/8] Fix a bug in scsi_get_command
2005-11-18 19:32 [RFC][PATCH 0/8] Critical Page Pool Matthew Dobson
` (2 preceding siblings ...)
2005-11-18 19:40 ` [RFC][PATCH 3/8] Slab cleanup Matthew Dobson
@ 2005-11-18 19:41 ` Matthew Dobson
2005-11-18 19:43 ` [RFC][PATCH 5/8] get_object/return_object Matthew Dobson
` (7 subsequent siblings)
11 siblings, 0 replies; 28+ messages in thread
From: Matthew Dobson @ 2005-11-18 19:41 UTC (permalink / raw)
To: linux-kernel; +Cc: Linux Memory Management
[-- Attachment #1: Type: text/plain, Size: 104 bytes --]
Testing this patch series uncovered a small bug in scsi_get_command. This
patch fixes that bug.
-Matt
[-- Attachment #2: scsi_get_command-fix.patch --]
[-- Type: text/x-patch, Size: 958 bytes --]
scsi_get_command() attempts to write into a structure that may not have been
successfully allocated. Move this write inside the if statement that ensures
we won't panic the kernel with a NULL pointer dereference.
Signed-off-by: Matthew Dobson <colpatch@us.ibm.com>
Index: linux-2.6.15-rc1+critical_pool/drivers/scsi/scsi.c
===================================================================
--- linux-2.6.15-rc1+critical_pool.orig/drivers/scsi/scsi.c 2005-11-15 13:45:38.000000000 -0800
+++ linux-2.6.15-rc1+critical_pool/drivers/scsi/scsi.c 2005-11-17 16:49:54.279656112 -0800
@@ -265,10 +265,10 @@ struct scsi_cmnd *scsi_get_command(struc
spin_lock_irqsave(&dev->list_lock, flags);
list_add_tail(&cmd->list, &dev->cmd_list);
spin_unlock_irqrestore(&dev->list_lock, flags);
+ cmd->jiffies_at_alloc = jiffies;
} else
put_device(&dev->sdev_gendev);
- cmd->jiffies_at_alloc = jiffies;
return cmd;
}
EXPORT_SYMBOL(scsi_get_command);
^ permalink raw reply [flat|nested] 28+ messages in thread
* [RFC][PATCH 5/8] get_object/return_object
2005-11-18 19:32 [RFC][PATCH 0/8] Critical Page Pool Matthew Dobson
` (3 preceding siblings ...)
2005-11-18 19:41 ` [RFC][PATCH 4/8] Fix a bug in scsi_get_command Matthew Dobson
@ 2005-11-18 19:43 ` Matthew Dobson
2005-11-18 19:44 ` [RFC][PATCH 6/8] slab_destruct Matthew Dobson
` (6 subsequent siblings)
11 siblings, 0 replies; 28+ messages in thread
From: Matthew Dobson @ 2005-11-18 19:43 UTC (permalink / raw)
To: linux-kernel; +Cc: Linux Memory Management
[-- Attachment #1: Type: text/plain, Size: 88 bytes --]
Move the code to get/return an object back to its slab into their own
functions.
-Matt
[-- Attachment #2: slab_prep-get_return_object.patch --]
[-- Type: text/x-patch, Size: 3855 bytes --]
Create two helper functions: get_object_from_slab() & return_object_to_slab().
Use these two helper function to replace duplicated code in mm/slab.c
These functions will also be reused by a later patch in this series.
Signed-off-by: Matthew Dobson <colpatch@us.ibm.com>
Index: linux-2.6.15-rc1+critical_pool/mm/slab.c
===================================================================
--- linux-2.6.15-rc1+critical_pool.orig/mm/slab.c 2005-11-17 16:39:24.401412160 -0800
+++ linux-2.6.15-rc1+critical_pool/mm/slab.c 2005-11-17 16:45:07.337277984 -0800
@@ -2148,6 +2148,42 @@ static void kmem_flagcheck(kmem_cache_t
}
}
+static void *get_object(kmem_cache_t *cachep, struct slab *slabp, int nid)
+{
+ void *obj = slabp->s_mem + (slabp->free * cachep->objsize);
+ kmem_bufctl_t next;
+
+ slabp->inuse++;
+ next = slab_bufctl(slabp)[slabp->free];
+#if DEBUG
+ slab_bufctl(slabp)[slabp->free] = BUFCTL_FREE;
+ WARN_ON(slabp->nid != nid);
+#endif
+ slabp->free = next;
+
+ return obj;
+}
+
+static void return_object(kmem_cache_t *cachep, struct slab *slabp, void *objp,
+ int nid)
+{
+ unsigned int objnr = (objp - slabp->s_mem) / cachep->objsize;
+
+#if DEBUG
+ /* Verify that the slab belongs to the intended node */
+ WARN_ON(slabp->nid != nid);
+
+ if (slab_bufctl(slabp)[objnr] != BUFCTL_FREE) {
+ printk(KERN_ERR "slab: double free detected in cache "
+ "'%s', objp %p\n", cachep->name, objp);
+ BUG();
+ }
+#endif
+ slab_bufctl(slabp)[objnr] = slabp->free;
+ slabp->free = objnr;
+ slabp->inuse--;
+}
+
static void set_slab_attr(kmem_cache_t *cachep, struct slab *slabp, void *objp)
{
int i;
@@ -2436,22 +2472,12 @@ retry:
check_slabp(cachep, slabp);
check_spinlock_acquired(cachep);
while (slabp->inuse < cachep->num && batchcount--) {
- kmem_bufctl_t next;
STATS_INC_ALLOCED(cachep);
STATS_INC_ACTIVE(cachep);
STATS_SET_HIGH(cachep);
- /* get obj pointer */
- ac->entry[ac->avail++] = slabp->s_mem +
- slabp->free*cachep->objsize;
-
- slabp->inuse++;
- next = slab_bufctl(slabp)[slabp->free];
-#if DEBUG
- slab_bufctl(slabp)[slabp->free] = BUFCTL_FREE;
- WARN_ON(numa_node_id() != slabp->nid);
-#endif
- slabp->free = next;
+ ac->entry[ac->avail++] = get_object(cachep, slabp,
+ numa_node_id());
}
check_slabp(cachep, slabp);
@@ -2586,7 +2612,6 @@ static void *__cache_alloc_node(kmem_cac
struct slab *slabp;
struct kmem_list3 *l3;
void *obj;
- kmem_bufctl_t next;
int x;
l3 = cachep->nodelists[nid];
@@ -2612,14 +2637,7 @@ retry:
BUG_ON(slabp->inuse == cachep->num);
- /* get obj pointer */
- obj = slabp->s_mem + slabp->free * cachep->objsize;
- slabp->inuse++;
- next = slab_bufctl(slabp)[slabp->free];
-#if DEBUG
- slab_bufctl(slabp)[slabp->free] = BUFCTL_FREE;
-#endif
- slabp->free = next;
+ obj = get_object(cachep, slabp, nid);
check_slabp(cachep, slabp);
l3->free_objects--;
/* move slabp to correct slabp list: */
@@ -2659,29 +2677,14 @@ static void free_block(kmem_cache_t *cac
for (i = 0; i < nr_objects; i++) {
void *objp = objpp[i];
struct slab *slabp;
- unsigned int objnr;
slabp = GET_PAGE_SLAB(virt_to_page(objp));
l3 = cachep->nodelists[nid];
list_del(&slabp->list);
- objnr = (objp - slabp->s_mem) / cachep->objsize;
check_spinlock_acquired_node(cachep, nid);
check_slabp(cachep, slabp);
-
-#if DEBUG
- /* Verify that the slab belongs to the intended node */
- WARN_ON(slabp->nid != nid);
-
- if (slab_bufctl(slabp)[objnr] != BUFCTL_FREE) {
- printk(KERN_ERR "slab: double free detected in cache "
- "'%s', objp %p\n", cachep->name, objp);
- BUG();
- }
-#endif
- slab_bufctl(slabp)[objnr] = slabp->free;
- slabp->free = objnr;
+ return_object(cachep, slabp, objp, nid);
STATS_DEC_ACTIVE(cachep);
- slabp->inuse--;
l3->free_objects++;
check_slabp(cachep, slabp);
^ permalink raw reply [flat|nested] 28+ messages in thread
* [RFC][PATCH 6/8] slab_destruct
2005-11-18 19:32 [RFC][PATCH 0/8] Critical Page Pool Matthew Dobson
` (4 preceding siblings ...)
2005-11-18 19:43 ` [RFC][PATCH 5/8] get_object/return_object Matthew Dobson
@ 2005-11-18 19:44 ` Matthew Dobson
2005-11-18 19:44 ` [RFC][PATCH 0/8] Critical Page Pool Avi Kivity
` (5 subsequent siblings)
11 siblings, 0 replies; 28+ messages in thread
From: Matthew Dobson @ 2005-11-18 19:44 UTC (permalink / raw)
To: linux-kernel; +Cc: Linux Memory Management
[-- Attachment #1: Type: text/plain, Size: 161 bytes --]
Break the current slab_destroy() into 2 functions: slab_destroy and
slab_destruct. slab_destruct calls the destructor code and any necessary
debug code.
-Matt
[-- Attachment #2: slab_prep-slab_destruct.patch --]
[-- Type: text/x-patch, Size: 2082 bytes --]
Create a helper function, slab_destruct(), called from slab_destroy(). This
makes slab_destroy() smaller and more readable, and moves ifdefs outside the
function body.
Signed-off-by: Matthew Dobson <colpatch@us.ibm.com>
Index: linux-2.6.14+critical_pool/mm/slab.c
===================================================================
--- linux-2.6.14+critical_pool.orig/mm/slab.c 2005-11-14 10:52:22.427207392 -0800
+++ linux-2.6.14+critical_pool/mm/slab.c 2005-11-14 10:52:27.514434016 -0800
@@ -1388,16 +1388,13 @@ static void check_poison_obj(kmem_cache_
}
#endif
-/*
- * Destroy all the objs in a slab, and release the mem back to the system.
- * Before calling the slab must have been unlinked from the cache.
- * The cache-lock is not held/needed.
+#if DEBUG
+/**
+ * slab_destruct - call the registered destructor for each object in
+ * a slab that is to be destroyed.
*/
-static void slab_destroy(kmem_cache_t *cachep, struct slab *slabp)
+static void slab_destruct(kmem_cache_t *cachep, struct slab *slabp)
{
- void *addr = slabp->s_mem - slabp->colouroff;
-
-#if DEBUG
int i;
for (i = 0; i < cachep->num; i++) {
void *objp = slabp->s_mem + cachep->objsize * i;
@@ -1425,7 +1422,10 @@ static void slab_destroy(kmem_cache_t *c
if (cachep->dtor && !(cachep->flags & SLAB_POISON))
(cachep->dtor)(objp + obj_dbghead(cachep), cachep, 0);
}
+}
#else
+static void slab_destruct(kmem_cache_t *cachep, struct slab *slabp)
+{
if (cachep->dtor) {
int i;
for (i = 0; i < cachep->num; i++) {
@@ -1433,8 +1433,19 @@ static void slab_destroy(kmem_cache_t *c
(cachep->dtor)(objp, cachep, 0);
}
}
+}
#endif
+/**
+ * Destroy all the objs in a slab, and release the mem back to the system.
+ * Before calling the slab must have been unlinked from the cache.
+ * The cache-lock is not held/needed.
+ */
+static void slab_destroy(kmem_cache_t *cachep, struct slab *slabp)
+{
+ void *addr = slabp->s_mem - slabp->colouroff;
+
+ slab_destruct(cachep, slabp);
if (unlikely(cachep->flags & SLAB_DESTROY_BY_RCU)) {
struct slab_rcu *slab_rcu;
^ permalink raw reply [flat|nested] 28+ messages in thread
* Re: [RFC][PATCH 0/8] Critical Page Pool
2005-11-18 19:32 [RFC][PATCH 0/8] Critical Page Pool Matthew Dobson
` (5 preceding siblings ...)
2005-11-18 19:44 ` [RFC][PATCH 6/8] slab_destruct Matthew Dobson
@ 2005-11-18 19:44 ` Avi Kivity
2005-11-18 19:51 ` Matthew Dobson
2005-11-18 19:45 ` [RFC][PATCH 7/8] __cache_grow() Matthew Dobson
` (4 subsequent siblings)
11 siblings, 1 reply; 28+ messages in thread
From: Avi Kivity @ 2005-11-18 19:44 UTC (permalink / raw)
To: Matthew Dobson; +Cc: linux-kernel, Linux Memory Management
Matthew Dobson wrote:
>We have a clustering product that needs to be able to guarantee that the
>networking system won't stop functioning in the case of OOM/low memory
>condition. The current mempool system is inadequate because to keep the
>whole networking stack functioning, we need more than 1 or 2 slab caches to
>be guaranteed. We need to guarantee that any request made with a specific
>flag will succeed, assuming of course that you've made your "critical page
>pool" big enough.
>
>The following patch series implements such a critical page pool. It
>creates 2 userspace triggers:
>
>/proc/sys/vm/critical_pages: write the number of pages you want to reserve
>for the critical pool into this file
>
>/proc/sys/vm/in_emergency: write a non-zero value to tell the kernel that
>the system is in an emergency state and authorize the kernel to dip into
>the critical pool to satisfy critical allocations.
>
>We mark critical allocations with the __GFP_CRITICAL flag, and when the
>system is in an emergency state, we are allowed to delve into this pool to
>satisfy __GFP_CRITICAL allocations that cannot be satisfied through the
>normal means.
>
>
>
1. If you have two subsystems which allocate critical pages, how do you
protect against the condition where one subsystem allocates all the
critical memory, causing the second to oom?
2. There already exists a critical pool: ordinary allocations fail if
free memory is below some limit, but special processes (kswapd) can
allocate that memory by setting PF_MEMALLOC. Perhaps this should be
extended, possibly with a per-process threshold.
--
Do not meddle in the internals of kernels, for they are subtle and quick to panic.
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply [flat|nested] 28+ messages in thread
* [RFC][PATCH 7/8] __cache_grow()
2005-11-18 19:32 [RFC][PATCH 0/8] Critical Page Pool Matthew Dobson
` (6 preceding siblings ...)
2005-11-18 19:44 ` [RFC][PATCH 0/8] Critical Page Pool Avi Kivity
@ 2005-11-18 19:45 ` Matthew Dobson
2005-11-18 19:47 ` [RFC][PATCH 8/8] Add support critical pool support to the slab allocator Matthew Dobson
` (3 subsequent siblings)
11 siblings, 0 replies; 28+ messages in thread
From: Matthew Dobson @ 2005-11-18 19:45 UTC (permalink / raw)
To: linux-kernel; +Cc: Linux Memory Management
[-- Attachment #1: Type: text/plain, Size: 125 bytes --]
Create a helper for cache_grow() that handles doing the cache coloring and
allocating & initializing the struct slab.
-Matt
[-- Attachment #2: slab_prep-__cache_grow.patch --]
[-- Type: text/x-patch, Size: 6001 bytes --]
Create a helper function, __cache_grow(), called by cache_grow(). This allows
us to move the cache coloring and struct slab allocation & initialization to
its own discrete function.
Also, move both functions below some debugging function definitions, so they can be used
in these functions by the next patch without needing forward declarations.
Signed-off-by: Matthew Dobson <colpatch@us.ibm.com>
Index: linux-2.6.15-rc1+critical_pool/mm/slab.c
===================================================================
--- linux-2.6.15-rc1+critical_pool.orig/mm/slab.c 2005-11-17 16:45:09.979876248 -0800
+++ linux-2.6.15-rc1+critical_pool/mm/slab.c 2005-11-17 16:49:45.118048888 -0800
@@ -2209,95 +2209,6 @@ static void set_slab_attr(kmem_cache_t *
}
}
-/*
- * Grow (by 1) the number of slabs within a cache. This is called by
- * kmem_cache_alloc() when there are no active objs left in a cache.
- */
-static int cache_grow(kmem_cache_t *cachep, gfp_t flags, int nid)
-{
- struct slab *slabp;
- void *objp;
- size_t offset;
- gfp_t local_flags;
- unsigned long ctor_flags;
- struct kmem_list3 *l3;
-
- /*
- * Be lazy and only check for valid flags here,
- * keeping it out of the critical path in kmem_cache_alloc().
- */
- if (flags & ~(SLAB_DMA|SLAB_LEVEL_MASK|SLAB_NO_GROW))
- BUG();
- if (flags & SLAB_NO_GROW)
- return 0;
-
- ctor_flags = SLAB_CTOR_CONSTRUCTOR;
- local_flags = (flags & SLAB_LEVEL_MASK);
- if (!(local_flags & __GFP_WAIT))
- /*
- * Not allowed to sleep. Need to tell a constructor about
- * this - it might need to know...
- */
- ctor_flags |= SLAB_CTOR_ATOMIC;
-
- /* About to mess with non-constant members - lock. */
- check_irq_off();
- spin_lock(&cachep->spinlock);
-
- /* Get colour for the slab, and cal the next value. */
- offset = cachep->colour_next;
- cachep->colour_next++;
- if (cachep->colour_next >= cachep->colour)
- cachep->colour_next = 0;
- offset *= cachep->colour_off;
-
- spin_unlock(&cachep->spinlock);
-
- check_irq_off();
- if (local_flags & __GFP_WAIT)
- local_irq_enable();
-
- /*
- * Ensure caller isn't asking for DMA memory if the slab wasn't created
- * with the SLAB_DMA flag.
- * Also ensure the caller *is* asking for DMA memory if the slab was
- * created with the SLAB_DMA flag.
- */
- kmem_flagcheck(cachep, flags);
-
- /* Get mem for the objects by allocating a physical page from 'nid' */
- if (!(objp = kmem_getpages(cachep, flags, nid)))
- goto out_nomem;
-
- /* Get slab management. */
- if (!(slabp = alloc_slabmgmt(cachep, objp, offset, local_flags)))
- goto out_freepages;
-
- slabp->nid = nid;
- set_slab_attr(cachep, slabp, objp);
-
- cache_init_objs(cachep, slabp, ctor_flags);
-
- if (local_flags & __GFP_WAIT)
- local_irq_disable();
- check_irq_off();
- l3 = cachep->nodelists[nid];
- spin_lock(&l3->list_lock);
-
- /* Make slab active. */
- list_add_tail(&slabp->list, &(l3->slabs_free));
- STATS_INC_GROWN(cachep);
- l3->free_objects += cachep->num;
- spin_unlock(&l3->list_lock);
- return 1;
-out_freepages:
- kmem_freepages(cachep, objp);
-out_nomem:
- if (local_flags & __GFP_WAIT)
- local_irq_disable();
- return 0;
-}
-
#if DEBUG
/*
* Perform extra freeing checks:
@@ -2430,6 +2341,105 @@ bad:
#define check_slabp(x,y) do { } while(0)
#endif
+/**
+ * Helper function for cache_grow(). Handle cache coloring, allocating a
+ * struct slab and initializing the slab.
+ */
+static struct slab *__cache_grow(kmem_cache_t *cachep, void *objp, gfp_t flags)
+{
+ struct slab *slabp;
+ size_t offset;
+ unsigned int local_flags;
+ unsigned long ctor_flags;
+
+ ctor_flags = SLAB_CTOR_CONSTRUCTOR;
+ local_flags = (flags & SLAB_LEVEL_MASK);
+ if (!(local_flags & __GFP_WAIT))
+ /*
+ * Not allowed to sleep. Need to tell a constructor about
+ * this - it might need to know...
+ */
+ ctor_flags |= SLAB_CTOR_ATOMIC;
+
+ /* About to mess with non-constant members - lock. */
+ check_irq_off();
+ spin_lock(&cachep->spinlock);
+
+ /* Get colour for the slab, and cal the next value. */
+ offset = cachep->colour_next;
+ cachep->colour_next++;
+ if (cachep->colour_next >= cachep->colour)
+ cachep->colour_next = 0;
+ offset *= cachep->colour_off;
+
+ spin_unlock(&cachep->spinlock);
+
+ check_irq_off();
+ if (local_flags & __GFP_WAIT)
+ local_irq_enable();
+
+ /* Get slab management. */
+ if (!(slabp = alloc_slabmgmt(cachep, objp, offset, local_flags)))
+ goto out;
+
+ set_slab_attr(cachep, slabp, objp);
+ cache_init_objs(cachep, slabp, ctor_flags);
+
+out:
+ if (local_flags & __GFP_WAIT)
+ local_irq_disable();
+ check_irq_off();
+ return slabp;
+}
+
+/**
+ * Grow (by 1) the number of slabs within a cache. This is called by
+ * kmem_cache_alloc() when there are no active objs left in a cache.
+ */
+static int cache_grow(kmem_cache_t *cachep, gfp_t flags, int nid)
+{
+ struct slab *slabp = NULL;
+ void *objp = NULL;
+
+ /*
+ * Be lazy and only check for valid flags here,
+ * keeping it out of the critical path in kmem_cache_alloc().
+ */
+ if (flags & ~(SLAB_DMA|SLAB_LEVEL_MASK|SLAB_NO_GROW))
+ BUG();
+ if (flags & SLAB_NO_GROW)
+ goto out;
+
+ /*
+ * Ensure caller isn't asking for DMA memory if the slab wasn't created
+ * with the SLAB_DMA flag.
+ * Also ensure the caller *is* asking for DMA memory if the slab was
+ * created with the SLAB_DMA flag.
+ */
+ kmem_flagcheck(cachep, flags);
+
+ /* Get mem for the objects by allocating a physical page from 'nid' */
+ if ((objp = kmem_getpages(cachep, flags, nid))) {
+ struct kmem_list3 *l3 = cachep->nodelists[nid];
+
+ if (!(slabp = __cache_grow(cachep, objp, flags))) {
+ kmem_freepages(cachep, objp);
+ objp = NULL;
+ goto out;
+ }
+ slabp->nid = nid;
+
+ STATS_INC_GROWN(cachep);
+ /* Make slab active. */
+ spin_lock(&l3->list_lock);
+ list_add_tail(&slabp->list, &l3->slabs_free);
+ l3->free_objects += cachep->num;
+ spin_unlock(&l3->list_lock);
+ }
+out:
+ return objp != NULL;
+}
+
static void *cache_alloc_refill(kmem_cache_t *cachep, gfp_t flags)
{
int batchcount;
^ permalink raw reply [flat|nested] 28+ messages in thread
* [RFC][PATCH 8/8] Add support critical pool support to the slab allocator
2005-11-18 19:32 [RFC][PATCH 0/8] Critical Page Pool Matthew Dobson
` (7 preceding siblings ...)
2005-11-18 19:45 ` [RFC][PATCH 7/8] __cache_grow() Matthew Dobson
@ 2005-11-18 19:47 ` Matthew Dobson
2005-11-18 19:56 ` [RFC][PATCH 0/8] Critical Page Pool Chris Wright
` (2 subsequent siblings)
11 siblings, 0 replies; 28+ messages in thread
From: Matthew Dobson @ 2005-11-18 19:47 UTC (permalink / raw)
To: linux-kernel; +Cc: Linux Memory Management
[-- Attachment #1: Type: text/plain, Size: 145 bytes --]
Finally, teach the slab allocator how to deal with critical pages and how
to keep them for use exclusively by __GFP_CRITICAL allocations.
-Matt
[-- Attachment #2: slab_support.patch --]
[-- Type: text/x-patch, Size: 6638 bytes --]
Modify the Slab Allocator to support the addition of a Critical Pool to the VM.
What we want is to ensure that if a cache is allocated a new slab page from the
Critical Pool during an Emergency situation, that only other __GFP_CRITICAL
allocations are satisfied from that slab.
Signed-off-by: Matthew Dobson <colpatch@us.ibm.com>
Index: linux-2.6.15-rc1+critical_pool/mm/slab.c
===================================================================
--- linux-2.6.15-rc1+critical_pool.orig/mm/slab.c 2005-11-17 16:51:22.965173864 -0800
+++ linux-2.6.15-rc1+critical_pool/mm/slab.c 2005-11-17 17:22:03.056437472 -0800
@@ -220,6 +220,7 @@ struct slab {
unsigned long colouroff;
void *s_mem; /* including colour offset */
unsigned int inuse; /* # of objs active in slab */
+ unsigned short critical; /* is this an critical slab? */
kmem_bufctl_t free;
unsigned short nid; /* node number slab is on */
};
@@ -395,6 +396,9 @@ struct kmem_cache {
unsigned int slab_size;
unsigned int dflags; /* dynamic flags */
+ /* list of critical slabs for this cache */
+ struct list_head slabs_crit;
+
/* constructor func */
void (*ctor)(void *, kmem_cache_t *, unsigned long);
@@ -1770,6 +1774,7 @@ kmem_cache_t *kmem_cache_create(const ch
cachep->gfpflags |= GFP_DMA;
spin_lock_init(&cachep->spinlock);
cachep->objsize = size;
+ INIT_LIST_HEAD(&cachep->slabs_crit);
if (flags & CFLGS_OFF_SLAB)
cachep->slabp_cache = kmem_find_general_cachep(slab_size, 0u);
@@ -2090,6 +2095,7 @@ static struct slab *alloc_slabmgmt(kmem_
slabp->inuse = 0;
slabp->colouroff = colour_off;
slabp->s_mem = objp + colour_off;
+ slabp->critical = 0;
return slabp;
}
@@ -2182,7 +2188,8 @@ static void return_object(kmem_cache_t *
#if DEBUG
/* Verify that the slab belongs to the intended node */
- WARN_ON(slabp->nid != nid);
+ if (nid >= 0)
+ WARN_ON(slabp->nid != nid);
if (slab_bufctl(slabp)[objnr] != BUFCTL_FREE) {
printk(KERN_ERR "slab: double free detected in cache "
@@ -2341,6 +2348,24 @@ bad:
#define check_slabp(x,y) do { } while(0)
#endif
+static inline struct slab *get_critical_slab(kmem_cache_t *cachep, gfp_t flags)
+{
+ struct slab *slabp = NULL;
+
+ spin_lock(&cachep->spinlock);
+ /* search for any partially free critical slabs */
+ if (!list_empty(&cachep->slabs_crit)) {
+ list_for_each_entry(slabp, &cachep->slabs_crit, list)
+ if (slabp->free != BUFCTL_END)
+ goto found;
+ slabp = NULL;
+ }
+found:
+ spin_unlock(&cachep->spinlock);
+
+ return slabp;
+}
+
/**
* Helper function for cache_grow(). Handle cache coloring, allocating a
* struct slab and initializing the slab.
@@ -2396,10 +2421,11 @@ out:
* Grow (by 1) the number of slabs within a cache. This is called by
* kmem_cache_alloc() when there are no active objs left in a cache.
*/
-static int cache_grow(kmem_cache_t *cachep, gfp_t flags, int nid)
+static void *cache_grow(kmem_cache_t *cachep, gfp_t flags, int nid)
{
struct slab *slabp = NULL;
void *objp = NULL;
+ int critical = is_emergency_alloc(flags);
/*
* Be lazy and only check for valid flags here,
@@ -2411,6 +2437,13 @@ static int cache_grow(kmem_cache_t *cach
goto out;
/*
+ * We are in an emergency situation and this is a 'critical' alloc,
+ * so check if we've got an existing critical slab first
+ */
+ if (critical && (slabp = get_critical_slab(cachep, flags)))
+ goto got_critical_slab;
+
+ /*
* Ensure caller isn't asking for DMA memory if the slab wasn't created
* with the SLAB_DMA flag.
* Also ensure the caller *is* asking for DMA memory if the slab was
@@ -2431,13 +2464,34 @@ static int cache_grow(kmem_cache_t *cach
STATS_INC_GROWN(cachep);
/* Make slab active. */
- spin_lock(&l3->list_lock);
- list_add_tail(&slabp->list, &l3->slabs_free);
- l3->free_objects += cachep->num;
- spin_unlock(&l3->list_lock);
+ if (!critical) {
+ spin_lock(&l3->list_lock);
+ list_add_tail(&slabp->list, &l3->slabs_free);
+ l3->free_objects += cachep->num;
+ spin_unlock(&l3->list_lock);
+ } else {
+ spin_lock(&cachep->spinlock);
+ list_add_tail(&slabp->list, &cachep->slabs_crit);
+ slabp->critical = 1;
+ spin_unlock(&cachep->spinlock);
+got_critical_slab:
+ objp = get_object(cachep, slabp, nid);
+ check_slabp(cachep, slabp);
+ }
}
out:
- return objp != NULL;
+ return objp;
+}
+
+static inline int is_critical_object(void *obj)
+{
+ struct slab *slabp;
+
+ if (!obj)
+ return 0;
+
+ slabp = GET_PAGE_SLAB(virt_to_page(obj));
+ return slabp->critical;
}
static void *cache_alloc_refill(kmem_cache_t *cachep, gfp_t flags)
@@ -2516,12 +2570,15 @@ alloc_done:
spin_unlock(&l3->list_lock);
if (unlikely(!ac->avail)) {
- int x;
- x = cache_grow(cachep, flags, numa_node_id());
+ void *obj = cache_grow(cachep, flags, numa_node_id());
+
+ /* critical objects don't "grow" the slab, just return 'obj' */
+ if (is_critical_object(obj))
+ return obj;
/* cache_grow can reenable interrupts, then ac could change. */
ac = ac_data(cachep);
- if (!x && ac->avail == 0) /* no objects in sight? abort */
+ if (!obj && ac->avail == 0) /* No objects in sight? Abort. */
return NULL;
if (!ac->avail) /* objects refilled by interrupt? */
@@ -2633,7 +2690,6 @@ static void *__cache_alloc_node(kmem_cac
struct slab *slabp;
struct kmem_list3 *l3;
void *obj;
- int x;
l3 = cachep->nodelists[nid];
BUG_ON(!l3);
@@ -2675,11 +2731,15 @@ retry:
must_grow:
spin_unlock(&l3->list_lock);
- x = cache_grow(cachep, flags, nid);
+ obj = cache_grow(cachep, flags, nid);
- if (!x)
+ if (!obj)
return NULL;
+ /* critical objects don't "grow" the slab, just return 'obj' */
+ if (is_critical_object(obj))
+ goto done;
+
goto retry;
done:
return obj;
@@ -2780,6 +2840,22 @@ free_done:
sizeof(void *) * ac->avail);
}
+static inline void free_critical_object(kmem_cache_t *cachep, void *objp)
+{
+ struct slab *slabp = GET_PAGE_SLAB(virt_to_page(objp));
+
+ check_slabp(cachep, slabp);
+ return_object(cachep, slabp, objp, -1);
+ check_slabp(cachep, slabp);
+
+ if (slabp->inuse == 0) {
+ BUG_ON(cachep->flags & SLAB_DESTROY_BY_RCU);
+ BUG_ON(cachep->gfporder);
+
+ list_del(&slabp->list);
+ slab_destroy(cachep, slabp);
+ }
+}
/**
* __cache_free
@@ -2795,6 +2871,11 @@ static inline void __cache_free(kmem_cac
check_irq_off();
objp = cache_free_debugcheck(cachep, objp, __builtin_return_address(0));
+ if (is_critical_object(objp)) {
+ free_critical_object(cachep, objp);
+ return;
+ }
+
/*
* Make sure we are not freeing a object from another
* node to the array cache on this cpu.
^ permalink raw reply [flat|nested] 28+ messages in thread
* Re: [RFC][PATCH 0/8] Critical Page Pool
2005-11-18 19:44 ` [RFC][PATCH 0/8] Critical Page Pool Avi Kivity
@ 2005-11-18 19:51 ` Matthew Dobson
2005-11-18 20:42 ` Avi Kivity
0 siblings, 1 reply; 28+ messages in thread
From: Matthew Dobson @ 2005-11-18 19:51 UTC (permalink / raw)
To: Avi Kivity; +Cc: linux-kernel, Linux Memory Management
Avi Kivity wrote:
> Matthew Dobson wrote:
>
>> We have a clustering product that needs to be able to guarantee that the
>> networking system won't stop functioning in the case of OOM/low memory
>> condition. The current mempool system is inadequate because to keep the
>> whole networking stack functioning, we need more than 1 or 2 slab
>> caches to
>> be guaranteed. We need to guarantee that any request made with a
>> specific
>> flag will succeed, assuming of course that you've made your "critical
>> page
>> pool" big enough.
>>
>> The following patch series implements such a critical page pool. It
>> creates 2 userspace triggers:
>>
>> /proc/sys/vm/critical_pages: write the number of pages you want to
>> reserve
>> for the critical pool into this file
>>
>> /proc/sys/vm/in_emergency: write a non-zero value to tell the kernel that
>> the system is in an emergency state and authorize the kernel to dip into
>> the critical pool to satisfy critical allocations.
>>
>> We mark critical allocations with the __GFP_CRITICAL flag, and when the
>> system is in an emergency state, we are allowed to delve into this
>> pool to
>> satisfy __GFP_CRITICAL allocations that cannot be satisfied through the
>> normal means.
>>
>>
>>
> 1. If you have two subsystems which allocate critical pages, how do you
> protect against the condition where one subsystem allocates all the
> critical memory, causing the second to oom?
You don't. You make sure that you size the critical pool appropriately for
your workload.
> 2. There already exists a critical pool: ordinary allocations fail if
> free memory is below some limit, but special processes (kswapd) can
> allocate that memory by setting PF_MEMALLOC. Perhaps this should be
> extended, possibly with a per-process threshold.
The exception for threads with PF_MEMALLOC set is there because those
threads are essentially promising that if the kernel gives them memory,
they will use that memory to free up MORE memory. If we ignore that
promise, and (ab)use the PF_MEMALLOC flag to simply bypass the
zone_watermarks, we'll simply OOM faster, and potentially in situations
that could be avoided (ie: we steal memory that kswapd could have used to
free up more memory).
Thanks for your feedback!
-Matt
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^ permalink raw reply [flat|nested] 28+ messages in thread
* Re: [RFC][PATCH 0/8] Critical Page Pool
2005-11-18 19:32 [RFC][PATCH 0/8] Critical Page Pool Matthew Dobson
` (8 preceding siblings ...)
2005-11-18 19:47 ` [RFC][PATCH 8/8] Add support critical pool support to the slab allocator Matthew Dobson
@ 2005-11-18 19:56 ` Chris Wright
2005-11-21 5:47 ` Matthew Dobson
2005-11-20 7:45 ` Keith Owens
2005-11-20 23:04 ` Pavel Machek
11 siblings, 1 reply; 28+ messages in thread
From: Chris Wright @ 2005-11-18 19:56 UTC (permalink / raw)
To: Matthew Dobson; +Cc: linux-kernel, Linux Memory Management
* Matthew Dobson (colpatch@us.ibm.com) wrote:
> /proc/sys/vm/critical_pages: write the number of pages you want to reserve
> for the critical pool into this file
How do you size this pool? Allocations are interrupt driven, so how to you
ensure you're allocating for the cluster network traffic you care about?
> /proc/sys/vm/in_emergency: write a non-zero value to tell the kernel that
> the system is in an emergency state and authorize the kernel to dip into
> the critical pool to satisfy critical allocations.
Seems odd to me. Why make this another knob? How did you run to set this
flag if you're in emergency and kswapd is going nuts?
thanks,
-chris
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^ permalink raw reply [flat|nested] 28+ messages in thread
* Re: [RFC][PATCH 0/8] Critical Page Pool
2005-11-18 19:51 ` Matthew Dobson
@ 2005-11-18 20:42 ` Avi Kivity
2005-11-19 0:10 ` Paul Jackson
2005-11-21 5:36 ` Matthew Dobson
0 siblings, 2 replies; 28+ messages in thread
From: Avi Kivity @ 2005-11-18 20:42 UTC (permalink / raw)
To: Matthew Dobson; +Cc: linux-kernel, Linux Memory Management
Matthew Dobson wrote:
>Avi Kivity wrote:
>
>
>>1. If you have two subsystems which allocate critical pages, how do you
>>protect against the condition where one subsystem allocates all the
>>critical memory, causing the second to oom?
>>
>>
>
>You don't. You make sure that you size the critical pool appropriately for
>your workload.
>
>
>
This may not be possible. What if subsystem A depends on subsystem B to
do its work, both are critical, and subsystem A allocated all the memory
reserve?
If A and B have different allocation thresholds, the deadlock is avoided.
At the very least you need a critical pool per subsystem.
>
>
>>2. There already exists a critical pool: ordinary allocations fail if
>>free memory is below some limit, but special processes (kswapd) can
>>allocate that memory by setting PF_MEMALLOC. Perhaps this should be
>>extended, possibly with a per-process threshold.
>>
>>
>
>The exception for threads with PF_MEMALLOC set is there because those
>threads are essentially promising that if the kernel gives them memory,
>they will use that memory to free up MORE memory. If we ignore that
>promise, and (ab)use the PF_MEMALLOC flag to simply bypass the
>zone_watermarks, we'll simply OOM faster, and potentially in situations
>that could be avoided (ie: we steal memory that kswapd could have used to
>free up more memory).
>
>
Sure, but that's just an example of a critical subsystem.
If we introduce yet another mechanism for critical memory allocation,
we'll have a hard time making different subsystems, which use different
critical allocation mechanisms, play well together.
I propose that instead of a single watermark, there should be a
watermark per critical subsystem. The watermarks would be arranged
according to the dependency graph, with the depended-on services allowed
to go the deepest into the reserves.
(instead of PF_MEMALLOC have a tsk->memory_allocation_threshold, or
similar. set it to 0 for kswapd, and for other systems according to taste)
--
Do not meddle in the internals of kernels, for they are subtle and quick to panic.
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^ permalink raw reply [flat|nested] 28+ messages in thread
* Re: [RFC][PATCH 1/8] Create Critical Page Pool
2005-11-18 19:36 ` [RFC][PATCH 1/8] Create " Matthew Dobson
@ 2005-11-19 0:08 ` Paul Jackson
2005-11-21 5:50 ` Matthew Dobson
0 siblings, 1 reply; 28+ messages in thread
From: Paul Jackson @ 2005-11-19 0:08 UTC (permalink / raw)
To: Matthew Dobson; +Cc: linux-kernel, linux-mm
Total nit:
#define __GFP_HARDWALL ((__force gfp_t)0x40000u) /* Enforce hardwall cpuset memory allocs */
+#define __GFP_CRITICAL ((__force gfp_t)0x80000u) /* Critical allocation. MUST succeed! */
Looks like you used a space instead of a tab.
--
I won't rest till it's the best ...
Programmer, Linux Scalability
Paul Jackson <pj@sgi.com> 1.925.600.0401
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^ permalink raw reply [flat|nested] 28+ messages in thread
* Re: [RFC][PATCH 0/8] Critical Page Pool
2005-11-18 20:42 ` Avi Kivity
@ 2005-11-19 0:10 ` Paul Jackson
2005-11-21 5:36 ` Matthew Dobson
1 sibling, 0 replies; 28+ messages in thread
From: Paul Jackson @ 2005-11-19 0:10 UTC (permalink / raw)
To: Avi Kivity; +Cc: colpatch, linux-kernel, linux-mm
Avi wrote:
> This may not be possible. What if subsystem A depends on subsystem B to
> do its work, both are critical, and subsystem A allocated all the memory
> reserve?
Apparently Matthew's subsystems have some knowable upper limits on
their critical memory needs, so that your scenario can be avoided.
--
I won't rest till it's the best ...
Programmer, Linux Scalability
Paul Jackson <pj@sgi.com> 1.925.600.0401
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^ permalink raw reply [flat|nested] 28+ messages in thread
* Re: [RFC][PATCH 2/8] Create emergency trigger
2005-11-18 19:36 ` [RFC][PATCH 2/8] Create emergency trigger Matthew Dobson
@ 2005-11-19 0:21 ` Paul Jackson
2005-11-21 5:51 ` Matthew Dobson
0 siblings, 1 reply; 28+ messages in thread
From: Paul Jackson @ 2005-11-19 0:21 UTC (permalink / raw)
To: Matthew Dobson; +Cc: linux-kernel, linux-mm
> @@ -876,6 +879,16 @@ __alloc_pages(gfp_t gfp_mask, unsigned i
> int can_try_harder;
> int did_some_progress;
>
> + if (is_emergency_alloc(gfp_mask)) {
Can this check for is_emergency_alloc be moved lower in __alloc_pages?
I don't see any reason why most __alloc_pages() calls, that succeed
easily in the first loop over the zonelist, have to make this check.
This would save one conditional test and jump on the most heavily
used code path in __alloc_pages().
--
I won't rest till it's the best ...
Programmer, Linux Scalability
Paul Jackson <pj@sgi.com> 1.925.600.0401
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^ permalink raw reply [flat|nested] 28+ messages in thread
* Re: [RFC][PATCH 0/8] Critical Page Pool
2005-11-18 19:32 [RFC][PATCH 0/8] Critical Page Pool Matthew Dobson
` (9 preceding siblings ...)
2005-11-18 19:56 ` [RFC][PATCH 0/8] Critical Page Pool Chris Wright
@ 2005-11-20 7:45 ` Keith Owens
2005-11-21 5:53 ` Matthew Dobson
2005-11-20 23:04 ` Pavel Machek
11 siblings, 1 reply; 28+ messages in thread
From: Keith Owens @ 2005-11-20 7:45 UTC (permalink / raw)
To: Matthew Dobson; +Cc: linux-kernel, Linux Memory Management
On Fri, 18 Nov 2005 11:32:57 -0800,
Matthew Dobson <colpatch@us.ibm.com> wrote:
>We have a clustering product that needs to be able to guarantee that the
>networking system won't stop functioning in the case of OOM/low memory
>condition. The current mempool system is inadequate because to keep the
>whole networking stack functioning, we need more than 1 or 2 slab caches to
>be guaranteed. We need to guarantee that any request made with a specific
>flag will succeed, assuming of course that you've made your "critical page
>pool" big enough.
>
>The following patch series implements such a critical page pool. It
>creates 2 userspace triggers:
>
>/proc/sys/vm/critical_pages: write the number of pages you want to reserve
>for the critical pool into this file
>
>/proc/sys/vm/in_emergency: write a non-zero value to tell the kernel that
>the system is in an emergency state and authorize the kernel to dip into
>the critical pool to satisfy critical allocations.
FWIW, the Kernel Debugger (KDB) has similar problems where the system
is dying because of lack of memory but KDB must call some functions
that use kmalloc. A related problem is that sometimes KDB is invoked
from a non maskable interrupt, so I could not even trust the state of
the spinlocks and the chains in the slab code.
I worked around the problem by adding a last ditch allocator. Extract
from the kdb patch.
---
/* Last ditch allocator for debugging, so we can still debug even when the
* GFP_ATOMIC pool has been exhausted. The algorithms are tuned for space
* usage, not for speed. One smallish memory pool, the free chain is always in
* ascending address order to allow coalescing, allocations are done in brute
* force best fit.
*/
struct debug_alloc_header {
u32 next; /* offset of next header from start of pool */
u32 size;
};
#define dah_align 8
static u64 debug_alloc_pool_aligned[64*1024/dah_align]; /* 64K pool */
static char *debug_alloc_pool = (char *)debug_alloc_pool_aligned;
static u32 dah_first;
/* Locking is awkward. The debug code is called from all contexts, including
* non maskable interrupts. A normal spinlock is not safe in NMI context. Try
* to get the debug allocator lock, if it cannot be obtained after a second
* then give up. If the lock could not be previously obtained on this cpu then
* only try once.
*/
static DEFINE_SPINLOCK(dap_lock);
static inline
int get_dap_lock(void)
{
static int dap_locked = -1;
int count;
if (dap_locked == smp_processor_id())
count = 1;
else
count = 1000;
while (1) {
if (spin_trylock(&dap_lock)) {
dap_locked = -1;
return 1;
}
if (!count--)
break;
udelay(1000);
}
dap_locked = smp_processor_id();
return 0;
}
void *debug_kmalloc(size_t size, int flags)
{
unsigned int rem, h_offset;
struct debug_alloc_header *best, *bestprev, *prev, *h;
void *p = NULL;
if ((p = kmalloc(size, flags)))
return p;
if (!get_dap_lock())
return NULL;
h = (struct debug_alloc_header *)(debug_alloc_pool + dah_first);
prev = best = bestprev = NULL;
while (1) {
if (h->size >= size && (!best || h->size < best->size)) {
best = h;
bestprev = prev;
}
if (!h->next)
break;
prev = h;
h = (struct debug_alloc_header *)(debug_alloc_pool + h->next);
}
if (!best)
goto out;
rem = (best->size - size) & -dah_align;
/* The pool must always contain at least one header */
if (best->next == 0 && bestprev == NULL && rem < sizeof(*h))
goto out;
if (rem >= sizeof(*h)) {
best->size = (size + dah_align - 1) & -dah_align;
h_offset = (char *)best - debug_alloc_pool + sizeof(*best) + best->size;
h = (struct debug_alloc_header *)(debug_alloc_pool + h_offset);
h->size = rem - sizeof(*h);
h->next = best->next;
} else
h_offset = best->next;
if (bestprev)
bestprev->next = h_offset;
else
dah_first = h_offset;
p = best+1;
out:
spin_unlock(&dap_lock);
return p;
}
void debug_kfree(const void *p)
{
struct debug_alloc_header *h;
unsigned int h_offset;
if (!p)
return;
if ((char *)p < debug_alloc_pool ||
(char *)p >= debug_alloc_pool + sizeof(debug_alloc_pool_aligned)) {
kfree(p);
return;
}
if (!get_dap_lock())
return; /* memory leak, cannot be helped */
h = (struct debug_alloc_header *)p - 1;
h_offset = (char *)h - debug_alloc_pool;
if (h_offset < dah_first) {
h->next = dah_first;
dah_first = h_offset;
} else {
struct debug_alloc_header *prev;
prev = (struct debug_alloc_header *)(debug_alloc_pool + dah_first);
while (1) {
if (!prev->next || prev->next > h_offset)
break;
prev = (struct debug_alloc_header *)(debug_alloc_pool + prev->next);
}
if (sizeof(*prev) + prev->size == h_offset) {
prev->size += sizeof(*h) + h->size;
h = prev;
h_offset = (char *)h - debug_alloc_pool;
} else {
h->next = prev->next;
prev->next = h_offset;
}
}
if (h_offset + sizeof(*h) + h->size == h->next) {
struct debug_alloc_header *next;
next = (struct debug_alloc_header *)(debug_alloc_pool + h->next);
h->size += sizeof(*next) + next->size;
h->next = next->next;
}
spin_unlock(&dap_lock);
}
void kdb_initsupport()
{
struct debug_alloc_header *h;
h = (struct debug_alloc_header *)debug_alloc_pool;
h->next = 0;
h->size = sizeof(debug_alloc_pool_aligned) - sizeof(*h);
dah_first = 0;
}
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^ permalink raw reply [flat|nested] 28+ messages in thread
* Re: [RFC][PATCH 0/8] Critical Page Pool
2005-11-18 19:32 [RFC][PATCH 0/8] Critical Page Pool Matthew Dobson
` (10 preceding siblings ...)
2005-11-20 7:45 ` Keith Owens
@ 2005-11-20 23:04 ` Pavel Machek
2005-11-21 5:58 ` Matthew Dobson
11 siblings, 1 reply; 28+ messages in thread
From: Pavel Machek @ 2005-11-20 23:04 UTC (permalink / raw)
To: Matthew Dobson; +Cc: linux-kernel, Linux Memory Management
On Fri 18-11-05 11:32:57, Matthew Dobson wrote:
> We have a clustering product that needs to be able to guarantee that the
> networking system won't stop functioning in the case of OOM/low memory
> condition. The current mempool system is inadequate because to keep the
> whole networking stack functioning, we need more than 1 or 2 slab caches to
> be guaranteed. We need to guarantee that any request made with a specific
> flag will succeed, assuming of course that you've made your "critical page
> pool" big enough.
>
> The following patch series implements such a critical page pool. It
> creates 2 userspace triggers:
>
> /proc/sys/vm/critical_pages: write the number of pages you want to reserve
> for the critical pool into this file
>
> /proc/sys/vm/in_emergency: write a non-zero value to tell the kernel that
> the system is in an emergency state and authorize the kernel to dip into
> the critical pool to satisfy critical allocations.
>
> We mark critical allocations with the __GFP_CRITICAL flag, and when the
> system is in an emergency state, we are allowed to delve into this pool to
> satisfy __GFP_CRITICAL allocations that cannot be satisfied through the
> normal means.
Ugh, relying on userspace to tell you that you need to dip into emergency
pool seems to be racy and unreliable. How can you guarantee that userspace
is scheduled soon enough in case of OOM?
Pavel
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^ permalink raw reply [flat|nested] 28+ messages in thread
* Re: [RFC][PATCH 0/8] Critical Page Pool
2005-11-18 20:42 ` Avi Kivity
2005-11-19 0:10 ` Paul Jackson
@ 2005-11-21 5:36 ` Matthew Dobson
1 sibling, 0 replies; 28+ messages in thread
From: Matthew Dobson @ 2005-11-21 5:36 UTC (permalink / raw)
To: Avi Kivity; +Cc: linux-kernel, Linux Memory Management
Appologies for the delay in responding to comments, but I have been en
route to the East Coast of the US to visit family.
Avi Kivity wrote:
> Matthew Dobson wrote:
>
>> Avi Kivity wrote:
>>
>>
>>> 1. If you have two subsystems which allocate critical pages, how do you
>>> protect against the condition where one subsystem allocates all the
>>> critical memory, causing the second to oom?
>>>
>>
>>
>> You don't. You make sure that you size the critical pool
>> appropriately for
>> your workload.
>>
>>
>>
> This may not be possible. What if subsystem A depends on subsystem B to
> do its work, both are critical, and subsystem A allocated all the memory
> reserve?
> If A and B have different allocation thresholds, the deadlock is avoided.
>
> At the very least you need a critical pool per subsystem.
As Paul suggested in his follow up to your mail, to even attempt a
"guarantee" that you won't still run out of memory, your subsystem does
need an upper bound on how much memory it could possibly need. If there is
NO upper limit, then the possibility of exhausting your critical pool is
very real.
>>> 2. There already exists a critical pool: ordinary allocations fail if
>>> free memory is below some limit, but special processes (kswapd) can
>>> allocate that memory by setting PF_MEMALLOC. Perhaps this should be
>>> extended, possibly with a per-process threshold.
>>>
>>
>>
>> The exception for threads with PF_MEMALLOC set is there because those
>> threads are essentially promising that if the kernel gives them memory,
>> they will use that memory to free up MORE memory. If we ignore that
>> promise, and (ab)use the PF_MEMALLOC flag to simply bypass the
>> zone_watermarks, we'll simply OOM faster, and potentially in situations
>> that could be avoided (ie: we steal memory that kswapd could have used to
>> free up more memory).
>>
>>
> Sure, but that's just an example of a critical subsystem.
>
> If we introduce yet another mechanism for critical memory allocation,
> we'll have a hard time making different subsystems, which use different
> critical allocation mechanisms, play well together.
>
> I propose that instead of a single watermark, there should be a
> watermark per critical subsystem. The watermarks would be arranged
> according to the dependency graph, with the depended-on services allowed
> to go the deepest into the reserves.
>
> (instead of PF_MEMALLOC have a tsk->memory_allocation_threshold, or
> similar. set it to 0 for kswapd, and for other systems according to taste)
Your idea is certainly an interesting approach to solving the problem. I'm
not sure it quite does what I'm looking for, but I'll have to think about
your idea some more to be sure. One problem is that networking doesn't
have a specific "task" associated with it, where we could set a
memory_allocation_threshold.
Thanks!
-Matt
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^ permalink raw reply [flat|nested] 28+ messages in thread
* Re: [RFC][PATCH 0/8] Critical Page Pool
2005-11-18 19:56 ` [RFC][PATCH 0/8] Critical Page Pool Chris Wright
@ 2005-11-21 5:47 ` Matthew Dobson
2005-11-21 13:29 ` Pavel Machek
0 siblings, 1 reply; 28+ messages in thread
From: Matthew Dobson @ 2005-11-21 5:47 UTC (permalink / raw)
To: Chris Wright; +Cc: linux-kernel, Linux Memory Management
Chris Wright wrote:
> * Matthew Dobson (colpatch@us.ibm.com) wrote:
>
>>/proc/sys/vm/critical_pages: write the number of pages you want to reserve
>>for the critical pool into this file
>
>
> How do you size this pool?
Trial and error. If you want networking to survive with no memory other
than the critical pool for 2 minutes, for example, you pick a random value,
block all other allocations (I have a test patch to do this), and send a
boatload of packets at the box. If it OOMs, you need a bigger pool.
Lather, rinse, repeat.
> Allocations are interrupt driven, so how to you
> ensure you're allocating for the cluster network traffic you care about?
On the receive side, you can't. :( You *have* to allocate an skbuff for
the packet, and only a couple levels up the networking 7-layer burrito can
you tell if you can toss the packet as non-critical or keep it. On the
send side, you can create a simple socket flag that tags all that socket's
SEND requests as critical.
>>/proc/sys/vm/in_emergency: write a non-zero value to tell the kernel that
>>the system is in an emergency state and authorize the kernel to dip into
>>the critical pool to satisfy critical allocations.
>
>
> Seems odd to me. Why make this another knob? How did you run to set this
> flag if you're in emergency and kswapd is going nuts?
We did this because we didn't want __GFP_CRITICAL allocations dipping into
the pool in the case of a transient low mem situation. In those cases we
want to force the task to do writeback to get a page (as usual), so that
the critical pool will be full when the system REALLY goes critical. We
also open the in_emergency file when the app starts so that we can just
write to it and don't need to try to open it when kswapd is going nuts.
-Matt
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^ permalink raw reply [flat|nested] 28+ messages in thread
* Re: [RFC][PATCH 1/8] Create Critical Page Pool
2005-11-19 0:08 ` Paul Jackson
@ 2005-11-21 5:50 ` Matthew Dobson
2005-11-21 5:54 ` Paul Jackson
0 siblings, 1 reply; 28+ messages in thread
From: Matthew Dobson @ 2005-11-21 5:50 UTC (permalink / raw)
To: Paul Jackson; +Cc: linux-kernel, linux-mm
Paul Jackson wrote:
> Total nit:
>
> #define __GFP_HARDWALL ((__force gfp_t)0x40000u) /* Enforce hardwall cpuset memory allocs */
> +#define __GFP_CRITICAL ((__force gfp_t)0x80000u) /* Critical allocation. MUST succeed! */
>
> Looks like you used a space instead of a tab.
It's a tab on my side... Maybe some whitespace munging by Thunderbird?
Will make sure it's definitely a tab on the next itteration.
-Matt
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^ permalink raw reply [flat|nested] 28+ messages in thread
* Re: [RFC][PATCH 2/8] Create emergency trigger
2005-11-19 0:21 ` Paul Jackson
@ 2005-11-21 5:51 ` Matthew Dobson
0 siblings, 0 replies; 28+ messages in thread
From: Matthew Dobson @ 2005-11-21 5:51 UTC (permalink / raw)
To: Paul Jackson; +Cc: linux-kernel, linux-mm
Paul Jackson wrote:
>>@@ -876,6 +879,16 @@ __alloc_pages(gfp_t gfp_mask, unsigned i
>> int can_try_harder;
>> int did_some_progress;
>>
>>+ if (is_emergency_alloc(gfp_mask)) {
>
>
> Can this check for is_emergency_alloc be moved lower in __alloc_pages?
>
> I don't see any reason why most __alloc_pages() calls, that succeed
> easily in the first loop over the zonelist, have to make this check.
> This would save one conditional test and jump on the most heavily
> used code path in __alloc_pages().
Good point, Paul. Will make sure that gets moved.
Thanks!
-Matt
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^ permalink raw reply [flat|nested] 28+ messages in thread
* Re: [RFC][PATCH 0/8] Critical Page Pool
2005-11-20 7:45 ` Keith Owens
@ 2005-11-21 5:53 ` Matthew Dobson
0 siblings, 0 replies; 28+ messages in thread
From: Matthew Dobson @ 2005-11-21 5:53 UTC (permalink / raw)
To: Keith Owens; +Cc: linux-kernel, Linux Memory Management
Keith Owens wrote:
> On Fri, 18 Nov 2005 11:32:57 -0800,
> Matthew Dobson <colpatch@us.ibm.com> wrote:
>
>>We have a clustering product that needs to be able to guarantee that the
>>networking system won't stop functioning in the case of OOM/low memory
>>condition. The current mempool system is inadequate because to keep the
>>whole networking stack functioning, we need more than 1 or 2 slab caches to
>>be guaranteed. We need to guarantee that any request made with a specific
>>flag will succeed, assuming of course that you've made your "critical page
>>pool" big enough.
>>
>>The following patch series implements such a critical page pool. It
>>creates 2 userspace triggers:
>>
>>/proc/sys/vm/critical_pages: write the number of pages you want to reserve
>>for the critical pool into this file
>>
>>/proc/sys/vm/in_emergency: write a non-zero value to tell the kernel that
>>the system is in an emergency state and authorize the kernel to dip into
>>the critical pool to satisfy critical allocations.
>
>
> FWIW, the Kernel Debugger (KDB) has similar problems where the system
> is dying because of lack of memory but KDB must call some functions
> that use kmalloc. A related problem is that sometimes KDB is invoked
> from a non maskable interrupt, so I could not even trust the state of
> the spinlocks and the chains in the slab code.
>
> I worked around the problem by adding a last ditch allocator. Extract
> from the kdb patch.
Ahh... very interesting. And dissapointingly much smaller than mine. :(
Thanks for the patch and the feedback!
-Matt
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^ permalink raw reply [flat|nested] 28+ messages in thread
* Re: [RFC][PATCH 1/8] Create Critical Page Pool
2005-11-21 5:50 ` Matthew Dobson
@ 2005-11-21 5:54 ` Paul Jackson
0 siblings, 0 replies; 28+ messages in thread
From: Paul Jackson @ 2005-11-21 5:54 UTC (permalink / raw)
To: Matthew Dobson; +Cc: linux-kernel, linux-mm
Matthew wrote:
> It's a tab on my side.
Oh - ok.
--
I won't rest till it's the best ...
Programmer, Linux Scalability
Paul Jackson <pj@sgi.com> 1.925.600.0401
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^ permalink raw reply [flat|nested] 28+ messages in thread
* Re: [RFC][PATCH 0/8] Critical Page Pool
2005-11-20 23:04 ` Pavel Machek
@ 2005-11-21 5:58 ` Matthew Dobson
0 siblings, 0 replies; 28+ messages in thread
From: Matthew Dobson @ 2005-11-21 5:58 UTC (permalink / raw)
To: Pavel Machek; +Cc: linux-kernel, Linux Memory Management
Pavel Machek wrote:
> On Fri 18-11-05 11:32:57, Matthew Dobson wrote:
>
>>We have a clustering product that needs to be able to guarantee that the
>>networking system won't stop functioning in the case of OOM/low memory
>>condition. The current mempool system is inadequate because to keep the
>>whole networking stack functioning, we need more than 1 or 2 slab caches to
>>be guaranteed. We need to guarantee that any request made with a specific
>>flag will succeed, assuming of course that you've made your "critical page
>>pool" big enough.
>>
>>The following patch series implements such a critical page pool. It
>>creates 2 userspace triggers:
>>
>>/proc/sys/vm/critical_pages: write the number of pages you want to reserve
>>for the critical pool into this file
>>
>>/proc/sys/vm/in_emergency: write a non-zero value to tell the kernel that
>>the system is in an emergency state and authorize the kernel to dip into
>>the critical pool to satisfy critical allocations.
>>
>>We mark critical allocations with the __GFP_CRITICAL flag, and when the
>>system is in an emergency state, we are allowed to delve into this pool to
>>satisfy __GFP_CRITICAL allocations that cannot be satisfied through the
>>normal means.
>
>
> Ugh, relying on userspace to tell you that you need to dip into emergency
> pool seems to be racy and unreliable. How can you guarantee that userspace
> is scheduled soon enough in case of OOM?
> Pavel
It's not really for userspace to tell us that we're about to OOM, as the
kernel is in a far better position to determine that. It is to let the
kernel know that *something* has gone wrong, and we've got to keep
networking (or any other user of __GFP_CRITICAL) up for a few minutes, *no
matter what*. We may not ever OOM, or even run terribly low on memory, but
the trigger allows the use of the pool IF that happens.
-Matt
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^ permalink raw reply [flat|nested] 28+ messages in thread
* Re: [RFC][PATCH 0/8] Critical Page Pool
2005-11-21 5:47 ` Matthew Dobson
@ 2005-11-21 13:29 ` Pavel Machek
2005-12-06 22:54 ` Matthew Dobson
0 siblings, 1 reply; 28+ messages in thread
From: Pavel Machek @ 2005-11-21 13:29 UTC (permalink / raw)
To: Matthew Dobson; +Cc: Chris Wright, linux-kernel, Linux Memory Management
Hi!
> > * Matthew Dobson (colpatch@us.ibm.com) wrote:
> >
> >>/proc/sys/vm/critical_pages: write the number of pages you want to reserve
> >>for the critical pool into this file
> >
> >
> > How do you size this pool?
>
> Trial and error. If you want networking to survive with no memory other
> than the critical pool for 2 minutes, for example, you pick a random value,
> block all other allocations (I have a test patch to do this), and send a
> boatload of packets at the box. If it OOMs, you need a bigger pool.
> Lather, rinse, repeat.
...and then you find out that your test was not "bad enough" or that
it needs more memory on different machines. It may be good enough hack
for your usage, but I do not think it belongs in mainline.
Pavel
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Thanks, Sharp!
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^ permalink raw reply [flat|nested] 28+ messages in thread
* Re: [RFC][PATCH 0/8] Critical Page Pool
2005-11-21 13:29 ` Pavel Machek
@ 2005-12-06 22:54 ` Matthew Dobson
2005-12-10 8:39 ` Pavel Machek
0 siblings, 1 reply; 28+ messages in thread
From: Matthew Dobson @ 2005-12-06 22:54 UTC (permalink / raw)
To: Pavel Machek; +Cc: Chris Wright, linux-kernel, Linux Memory Management
Pavel Machek wrote:
> Hi!
>
>
>>>* Matthew Dobson (colpatch@us.ibm.com) wrote:
>>>
>>>
>>>>/proc/sys/vm/critical_pages: write the number of pages you want to reserve
>>>>for the critical pool into this file
>>>
>>>
>>>How do you size this pool?
>>
>>Trial and error. If you want networking to survive with no memory other
>>than the critical pool for 2 minutes, for example, you pick a random value,
>>block all other allocations (I have a test patch to do this), and send a
>>boatload of packets at the box. If it OOMs, you need a bigger pool.
>>Lather, rinse, repeat.
>
>
> ...and then you find out that your test was not "bad enough" or that
> it needs more memory on different machines. It may be good enough hack
> for your usage, but I do not think it belongs in mainline.
> Pavel
Way late in responding to this, but...
Apropriate sizing of this pool is a known issue. For example, we want to
use it to keep the networking stack alive during extreme memory pressure
situations. The only way to size the pool so as to *guarantee* that it
will not be exhausted during the 2 minute window we need would be to ensure
that the pool has at least (TOTAL_BANDWITH_OF_ALL_NICS * 120 seconds) bytes
available. In the case of a simple system with a single GigE adapter we'd
need (1 gigbit/sec * 120 sec) = 120 gigabits = 15 gigabytes of reserve
pool. That is obviously completely impractical, considering many boxes
have multiple GigE adapters or even 10 GigE adapters. It is also
incredibly unlikely that the NIC will be hit with a continuous stream of
packets at a level that would completely saturate the link. Starting with
an educated guess and some test runs with a reasonble workload should give
you a good idea of how much space you'd *realistically* need to reserve.
Given any reserve size less than the theoretical maximum you obviously
can't *guarantee* the pool won't be exhausted, but you can be pretty confident.
-Matt
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^ permalink raw reply [flat|nested] 28+ messages in thread
* Re: [RFC][PATCH 0/8] Critical Page Pool
2005-12-06 22:54 ` Matthew Dobson
@ 2005-12-10 8:39 ` Pavel Machek
0 siblings, 0 replies; 28+ messages in thread
From: Pavel Machek @ 2005-12-10 8:39 UTC (permalink / raw)
To: Matthew Dobson; +Cc: Chris Wright, linux-kernel, Linux Memory Management
Hi!
> > ...and then you find out that your test was not "bad enough" or that
> > it needs more memory on different machines. It may be good enough hack
> > for your usage, but I do not think it belongs in mainline.
> > Pavel
>
> Way late in responding to this, but...
>
> Apropriate sizing of this pool is a known issue. For example, we want to
> use it to keep the networking stack alive during extreme memory pressure
> situations. The only way to size the pool so as to *guarantee* that it
> will not be exhausted during the 2 minute window we need would be to ensure
> that the pool has at least (TOTAL_BANDWITH_OF_ALL_NICS * 120 seconds) bytes
> available. In the case of a simple system with a single GigE adapter we'd
> need (1 gigbit/sec * 120 sec) = 120 gigabits = 15 gigabytes of reserve
> pool. That is obviously completely impractical, considering many boxes
And it is not enough... If someone hits you with small packets,
allocation overhead is going to be high.
Pavel
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Thanks, Sharp!
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^ permalink raw reply [flat|nested] 28+ messages in thread
end of thread, other threads:[~2005-12-10 8:39 UTC | newest]
Thread overview: 28+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2005-11-18 19:32 [RFC][PATCH 0/8] Critical Page Pool Matthew Dobson
2005-11-18 19:36 ` [RFC][PATCH 1/8] Create " Matthew Dobson
2005-11-19 0:08 ` Paul Jackson
2005-11-21 5:50 ` Matthew Dobson
2005-11-21 5:54 ` Paul Jackson
2005-11-18 19:36 ` [RFC][PATCH 2/8] Create emergency trigger Matthew Dobson
2005-11-19 0:21 ` Paul Jackson
2005-11-21 5:51 ` Matthew Dobson
2005-11-18 19:40 ` [RFC][PATCH 3/8] Slab cleanup Matthew Dobson
2005-11-18 19:41 ` [RFC][PATCH 4/8] Fix a bug in scsi_get_command Matthew Dobson
2005-11-18 19:43 ` [RFC][PATCH 5/8] get_object/return_object Matthew Dobson
2005-11-18 19:44 ` [RFC][PATCH 6/8] slab_destruct Matthew Dobson
2005-11-18 19:44 ` [RFC][PATCH 0/8] Critical Page Pool Avi Kivity
2005-11-18 19:51 ` Matthew Dobson
2005-11-18 20:42 ` Avi Kivity
2005-11-19 0:10 ` Paul Jackson
2005-11-21 5:36 ` Matthew Dobson
2005-11-18 19:45 ` [RFC][PATCH 7/8] __cache_grow() Matthew Dobson
2005-11-18 19:47 ` [RFC][PATCH 8/8] Add support critical pool support to the slab allocator Matthew Dobson
2005-11-18 19:56 ` [RFC][PATCH 0/8] Critical Page Pool Chris Wright
2005-11-21 5:47 ` Matthew Dobson
2005-11-21 13:29 ` Pavel Machek
2005-12-06 22:54 ` Matthew Dobson
2005-12-10 8:39 ` Pavel Machek
2005-11-20 7:45 ` Keith Owens
2005-11-21 5:53 ` Matthew Dobson
2005-11-20 23:04 ` Pavel Machek
2005-11-21 5:58 ` Matthew Dobson
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