From: Christoph Lameter <cl@linux.com>
To: Pekka Enberg <penberg@kernel.org>
Cc: Joonsoo Kim <js1304@gmail.com>,
Glauber Costa <glommer@parallels.com>,
linux-mm@kvack.org, David Rientjes <rientjes@google.com>,
elezegarcia@gmail.com
Subject: CK5 [06/18] Common alignment code
Date: Thu, 1 Nov 2012 21:47:43 +0000 [thread overview]
Message-ID: <0000013abdf1ada4-b617214c-efd0-47ab-a3bb-fb6b2a664458-000000@email.amazonses.com> (raw)
In-Reply-To: <20121101214538.971500204@linux.com>
Extract the code to do object alignment from the allocators.
Do the alignment calculations in slab_common so that the
__kmem_cache_create functions of the allocators do not have
to deal with alignment.
Signed-off-by: Christoph Lameter <cl@linux.com>
---
mm/slab.c | 20 --------------------
mm/slab.h | 3 +++
mm/slab_common.c | 32 ++++++++++++++++++++++++++++++--
mm/slob.c | 10 ----------
mm/slub.c | 38 +-------------------------------------
5 files changed, 34 insertions(+), 69 deletions(-)
Index: linux/mm/slab.h
===================================================================
--- linux.orig/mm/slab.h 2012-11-01 16:09:25.762843113 -0500
+++ linux/mm/slab.h 2012-11-01 16:12:12.705187852 -0500
@@ -32,6 +32,9 @@ extern struct list_head slab_caches;
/* The slab cache that manages slab cache information */
extern struct kmem_cache *kmem_cache;
+unsigned long calculate_alignment(unsigned long flags,
+ unsigned long align, unsigned long size);
+
/* Functions provided by the slab allocators */
extern int __kmem_cache_create(struct kmem_cache *, unsigned long flags);
Index: linux/mm/slab_common.c
===================================================================
--- linux.orig/mm/slab_common.c 2012-11-01 16:09:25.762843113 -0500
+++ linux/mm/slab_common.c 2012-11-01 16:12:12.705187852 -0500
@@ -73,6 +73,34 @@ static inline int kmem_cache_sanity_chec
#endif
/*
+ * Figure out what the alignment of the objects will be given a set of
+ * flags, a user specified alignment and the size of the objects.
+ */
+unsigned long calculate_alignment(unsigned long flags,
+ unsigned long align, unsigned long size)
+{
+ /*
+ * If the user wants hardware cache aligned objects then follow that
+ * suggestion if the object is sufficiently large.
+ *
+ * The hardware cache alignment cannot override the specified
+ * alignment though. If that is greater then use it.
+ */
+ if (flags & SLAB_HWCACHE_ALIGN) {
+ unsigned long ralign = cache_line_size();
+ while (size <= ralign / 2)
+ ralign /= 2;
+ align = max(align, ralign);
+ }
+
+ if (align < ARCH_SLAB_MINALIGN)
+ align = ARCH_SLAB_MINALIGN;
+
+ return ALIGN(align, sizeof(void *));
+}
+
+
+/*
* 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.
@@ -124,7 +152,7 @@ struct kmem_cache *kmem_cache_create(con
s = kmem_cache_zalloc(kmem_cache, GFP_KERNEL);
if (s) {
s->object_size = s->size = size;
- s->align = align;
+ s->align = calculate_alignment(flags, align, size);
s->ctor = ctor;
s->name = kstrdup(name, GFP_KERNEL);
if (!s->name) {
@@ -211,7 +239,7 @@ void __init create_boot_cache(struct kme
s->name = name;
s->size = s->object_size = size;
- s->align = ARCH_KMALLOC_MINALIGN;
+ s->align = calculate_alignment(flags, ARCH_KMALLOC_MINALIGN, size);
err = __kmem_cache_create(s, flags);
if (err)
Index: linux/mm/slob.c
===================================================================
--- linux.orig/mm/slob.c 2012-11-01 16:09:25.762843113 -0500
+++ linux/mm/slob.c 2012-11-01 16:12:12.705187852 -0500
@@ -123,7 +123,6 @@ static inline void clear_slob_page_free(
#define SLOB_UNIT sizeof(slob_t)
#define SLOB_UNITS(size) (((size) + SLOB_UNIT - 1)/SLOB_UNIT)
-#define SLOB_ALIGN L1_CACHE_BYTES
/*
* struct slob_rcu is inserted at the tail of allocated slob blocks, which
@@ -527,20 +526,11 @@ EXPORT_SYMBOL(ksize);
int __kmem_cache_create(struct kmem_cache *c, unsigned long flags)
{
- size_t align = c->size;
-
if (flags & SLAB_DESTROY_BY_RCU) {
/* leave room for rcu footer at the end of object */
c->size += sizeof(struct slob_rcu);
}
c->flags = flags;
- /* ignore alignment unless it's forced */
- c->align = (flags & SLAB_HWCACHE_ALIGN) ? SLOB_ALIGN : 0;
- if (c->align < ARCH_SLAB_MINALIGN)
- c->align = ARCH_SLAB_MINALIGN;
- if (c->align < align)
- c->align = align;
-
return 0;
}
Index: linux/mm/slub.c
===================================================================
--- linux.orig/mm/slub.c 2012-11-01 16:11:31.068603160 -0500
+++ linux/mm/slub.c 2012-11-01 16:12:12.705187852 -0500
@@ -2758,32 +2758,6 @@ static inline int calculate_order(int si
return -ENOSYS;
}
-/*
- * Figure out what the alignment of the objects will be.
- */
-static unsigned long calculate_alignment(unsigned long flags,
- unsigned long align, unsigned long size)
-{
- /*
- * If the user wants hardware cache aligned objects then follow that
- * suggestion if the object is sufficiently large.
- *
- * The hardware cache alignment cannot override the specified
- * alignment though. If that is greater then use it.
- */
- if (flags & SLAB_HWCACHE_ALIGN) {
- unsigned long ralign = cache_line_size();
- while (size <= ralign / 2)
- ralign /= 2;
- align = max(align, ralign);
- }
-
- if (align < ARCH_SLAB_MINALIGN)
- align = ARCH_SLAB_MINALIGN;
-
- return ALIGN(align, sizeof(void *));
-}
-
static void
init_kmem_cache_node(struct kmem_cache_node *n)
{
@@ -2917,7 +2891,6 @@ static int calculate_sizes(struct kmem_c
{
unsigned long flags = s->flags;
unsigned long size = s->object_size;
- unsigned long align = s->align;
int order;
/*
@@ -2989,19 +2962,11 @@ static int calculate_sizes(struct kmem_c
#endif
/*
- * Determine the alignment based on various parameters that the
- * user specified and the dynamic determination of cache line size
- * on bootup.
- */
- align = calculate_alignment(flags, align, s->object_size);
- s->align = align;
-
- /*
* SLUB stores one object immediately after another beginning from
* offset 0. In order to align the objects we have to simply size
* each object to conform to the alignment.
*/
- size = ALIGN(size, align);
+ size = ALIGN(size, s->align);
s->size = size;
if (forced_order >= 0)
order = forced_order;
@@ -3030,7 +2995,6 @@ static int calculate_sizes(struct kmem_c
s->max = s->oo;
return !!oo_objects(s->oo);
-
}
static int kmem_cache_open(struct kmem_cache *s, unsigned long flags)
Index: linux/mm/slab.c
===================================================================
--- linux.orig/mm/slab.c 2012-11-01 16:12:10.601158311 -0500
+++ linux/mm/slab.c 2012-11-01 16:12:12.705187852 -0500
@@ -2339,22 +2339,6 @@ __kmem_cache_create (struct kmem_cache *
size &= ~(BYTES_PER_WORD - 1);
}
- /* calculate 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. Except if
- * an object is really small, then squeeze multiple objects into
- * one cacheline.
- */
- ralign = cache_line_size();
- while (size <= ralign / 2)
- ralign /= 2;
- } else {
- ralign = BYTES_PER_WORD;
- }
-
/*
* Redzoning and user store require word alignment or possibly larger.
* Note this will be overridden by architecture or caller mandated
@@ -2371,10 +2355,6 @@ __kmem_cache_create (struct kmem_cache *
size &= ~(REDZONE_ALIGN - 1);
}
- /* 2) arch mandated alignment */
- if (ralign < ARCH_SLAB_MINALIGN) {
- ralign = ARCH_SLAB_MINALIGN;
- }
/* 3) caller mandated alignment */
if (ralign < cachep->align) {
ralign = cachep->align;
--
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next prev parent reply other threads:[~2012-11-01 21:47 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20121101214538.971500204@linux.com>
2012-11-01 21:46 ` CK5 [01/18] Use correct cpu_slab on dead cpu Christoph Lameter
2012-11-02 20:11 ` David Rientjes
2012-11-01 21:46 ` CK5 [02/18] slab: Simplify bootstrap Christoph Lameter
2012-11-02 20:22 ` David Rientjes
2012-11-05 15:11 ` Christoph Lameter
2012-11-01 21:47 ` CK5 [05/18] slab: Use the new create_boot_cache function to simplify bootstrap Christoph Lameter
2012-11-01 21:47 ` CK5 [03/18] create common functions for boot slab creation Christoph Lameter
2012-11-02 20:34 ` David Rientjes
2012-11-05 15:15 ` Christoph Lameter
2012-11-05 21:52 ` David Rientjes
2012-11-01 21:47 ` CK5 [04/18] slub: Use a statically allocated kmem_cache boot structure for bootstrap Christoph Lameter
2012-11-01 21:47 ` Christoph Lameter [this message]
2012-11-01 21:47 ` CK5 [07/18] Move kmalloc related function defs Christoph Lameter
2012-11-01 21:47 ` CK5 [12/18] Common constants for kmalloc boundaries Christoph Lameter
2012-11-01 21:48 ` CK5 [15/18] stat: Use size_t for sizes instead of unsigned Christoph Lameter
2012-11-01 21:48 ` CK5 [13/18] Common definition for the array of kmalloc caches Christoph Lameter
2012-11-01 21:48 ` CK5 [11/18] slab: rename nodelists to node Christoph Lameter
2012-11-01 21:48 ` CK5 [16/18] Common Kmalloc cache determination Christoph Lameter
2012-11-01 21:48 ` CK5 [14/18] Common function to create the kmalloc array Christoph Lameter
2012-11-01 21:48 ` CK5 [08/18] Common kmalloc slab index determination Christoph Lameter
2012-11-01 21:48 ` CK5 [09/18] slab: Use common kmalloc_index/kmalloc_size functions Christoph Lameter
2012-11-01 21:48 ` CK5 [17/18] slab: Rename list3/l3 to node Christoph Lameter
2012-11-01 21:48 ` CK5 [18/18] Common definition for kmem_cache_node Christoph Lameter
2012-11-01 21:55 ` CK5 [10/18] slab: Common name for the per node structures Christoph Lameter
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