* [PATCH v5 2/3] mm: add system wide stats items category
2024-08-09 19:10 [PATCH v5 0/3] Fixes for memmap accounting Pasha Tatashin
2024-08-09 19:10 ` [PATCH v5 1/3] mm: don't account memmap on failure Pasha Tatashin
@ 2024-08-09 19:10 ` Pasha Tatashin
2024-08-11 20:24 ` David Rientjes
2024-08-09 19:10 ` [PATCH v5 3/3] mm: don't account memmap per-node Pasha Tatashin
2 siblings, 1 reply; 9+ messages in thread
From: Pasha Tatashin @ 2024-08-09 19:10 UTC (permalink / raw)
To: akpm, linux-kernel, linux-mm, linux-cxl, cerasuolodomenico,
hannes, j.granados, lizhijian, muchun.song, nphamcs,
pasha.tatashin, rientjes, rppt, souravpanda, vbabka, willy,
dan.j.williams, yi.zhang, alison.schofield, david, yosryahmed
/proc/vmstat contains events and stats, events can only grow, but stats
can grow and shrink.
vmstat has the following:
-------------------------
NR_VM_ZONE_STAT_ITEMS: per-zone stats
NR_VM_NUMA_EVENT_ITEMS: per-numa events
NR_VM_NODE_STAT_ITEMS: per-numa stats
NR_VM_WRITEBACK_STAT_ITEMS: system-wide background-writeback and
dirty-throttling tresholds.
NR_VM_EVENT_ITEMS: system-wide events
-------------------------
Rename NR_VM_WRITEBACK_STAT_ITEMS to NR_VM_STAT_ITEMS, to track the
system-wide stats, we are going to add per-page metadata stats to this
category in the next patch.
Also delete unused writeback_stat_name() function.
Suggested-by: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Acked-by: David Hildenbrand <david@redhat.com>
---
include/linux/vmstat.h | 15 ++++-----------
mm/vmstat.c | 6 +++---
2 files changed, 7 insertions(+), 14 deletions(-)
diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h
index 23cd17942036..9ab4fa5e09b5 100644
--- a/include/linux/vmstat.h
+++ b/include/linux/vmstat.h
@@ -34,10 +34,11 @@ struct reclaim_stat {
unsigned nr_lazyfree_fail;
};
-enum writeback_stat_item {
+/* Stat data for system wide items */
+enum vm_stat_item {
NR_DIRTY_THRESHOLD,
NR_DIRTY_BG_THRESHOLD,
- NR_VM_WRITEBACK_STAT_ITEMS,
+ NR_VM_STAT_ITEMS,
};
#ifdef CONFIG_VM_EVENT_COUNTERS
@@ -514,21 +515,13 @@ static inline const char *lru_list_name(enum lru_list lru)
return node_stat_name(NR_LRU_BASE + lru) + 3; // skip "nr_"
}
-static inline const char *writeback_stat_name(enum writeback_stat_item item)
-{
- return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
- NR_VM_NUMA_EVENT_ITEMS +
- NR_VM_NODE_STAT_ITEMS +
- item];
-}
-
#if defined(CONFIG_VM_EVENT_COUNTERS) || defined(CONFIG_MEMCG)
static inline const char *vm_event_name(enum vm_event_item item)
{
return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
NR_VM_NUMA_EVENT_ITEMS +
NR_VM_NODE_STAT_ITEMS +
- NR_VM_WRITEBACK_STAT_ITEMS +
+ NR_VM_STAT_ITEMS +
item];
}
#endif /* CONFIG_VM_EVENT_COUNTERS || CONFIG_MEMCG */
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 04a1cb6cc636..6f8aa4766f16 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -1257,7 +1257,7 @@ const char * const vmstat_text[] = {
"pgdemote_khugepaged",
"nr_memmap",
"nr_memmap_boot",
- /* enum writeback_stat_item counters */
+ /* system-wide enum vm_stat_item counters */
"nr_dirty_threshold",
"nr_dirty_background_threshold",
@@ -1790,7 +1790,7 @@ static const struct seq_operations zoneinfo_op = {
#define NR_VMSTAT_ITEMS (NR_VM_ZONE_STAT_ITEMS + \
NR_VM_NUMA_EVENT_ITEMS + \
NR_VM_NODE_STAT_ITEMS + \
- NR_VM_WRITEBACK_STAT_ITEMS + \
+ NR_VM_STAT_ITEMS + \
(IS_ENABLED(CONFIG_VM_EVENT_COUNTERS) ? \
NR_VM_EVENT_ITEMS : 0))
@@ -1827,7 +1827,7 @@ static void *vmstat_start(struct seq_file *m, loff_t *pos)
global_dirty_limits(v + NR_DIRTY_BG_THRESHOLD,
v + NR_DIRTY_THRESHOLD);
- v += NR_VM_WRITEBACK_STAT_ITEMS;
+ v += NR_VM_STAT_ITEMS;
#ifdef CONFIG_VM_EVENT_COUNTERS
all_vm_events(v);
--
2.46.0.76.ge559c4bf1a-goog
^ permalink raw reply [flat|nested] 9+ messages in thread* [PATCH v5 3/3] mm: don't account memmap per-node
2024-08-09 19:10 [PATCH v5 0/3] Fixes for memmap accounting Pasha Tatashin
2024-08-09 19:10 ` [PATCH v5 1/3] mm: don't account memmap on failure Pasha Tatashin
2024-08-09 19:10 ` [PATCH v5 2/3] mm: add system wide stats items category Pasha Tatashin
@ 2024-08-09 19:10 ` Pasha Tatashin
2024-08-11 20:26 ` David Rientjes
2 siblings, 1 reply; 9+ messages in thread
From: Pasha Tatashin @ 2024-08-09 19:10 UTC (permalink / raw)
To: akpm, linux-kernel, linux-mm, linux-cxl, cerasuolodomenico,
hannes, j.granados, lizhijian, muchun.song, nphamcs,
pasha.tatashin, rientjes, rppt, souravpanda, vbabka, willy,
dan.j.williams, yi.zhang, alison.schofield, david, yosryahmed
Fix invalid access to pgdat during hot-remove operation:
ndctl users reported a GPF when trying to destroy a namespace:
$ ndctl destroy-namespace all -r all -f
Segmentation fault
dmesg:
Oops: general protection fault, probably for
non-canonical address 0xdffffc0000005650: 0000 [#1] PREEMPT SMP KASAN
PTI
KASAN: probably user-memory-access in range
[0x000000000002b280-0x000000000002b287]
CPU: 26 UID: 0 PID: 1868 Comm: ndctl Not tainted 6.11.0-rc1 #1
Hardware name: Dell Inc. PowerEdge R640/08HT8T, BIOS
2.20.1 09/13/2023
RIP: 0010:mod_node_page_state+0x2a/0x110
cxl-test users report a GPF when trying to unload the test module:
$ modrpobe -r cxl-test
dmesg
BUG: unable to handle page fault for address: 0000000000004200
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: Oops: 0000 [#1] PREEMPT SMP PTI
CPU: 0 UID: 0 PID: 1076 Comm: modprobe Tainted: G O N 6.11.0-rc1 #197
Tainted: [O]=OOT_MODULE, [N]=TEST
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/15
RIP: 0010:mod_node_page_state+0x6/0x90
Currently, when memory is hot-plugged or hot-removed the accounting is
done based on the assumption that memmap is allocated from the same node
as the hot-plugged/hot-removed memory, which is not always the case.
In addition, there are challenges with keeping the node id of the memory
that is being remove to the time when memmap accounting is actually
performed: since this is done after remove_pfn_range_from_zone(), and
also after remove_memory_block_devices(). Meaning that we cannot use
pgdat nor walking though memblocks to get the nid.
Given all of that, account the memmap overhead system wide instead.
For this we are going to be using global atomic counters, but given that
memmap size is rarely modified, and normally is only modified either
during early boot when there is only one CPU, or under a hotplug global
mutex lock, therefore there is no need for per-cpu optimizations.
Also, while we are here rename nr_memmap to nr_memmap_pages, and
nr_memmap_boot to nr_memmap_boot_pages to be self explanatory that the
units are in page count.
Reported-by: Yi Zhang <yi.zhang@redhat.com>
Closes: https://lore.kernel.org/linux-cxl/CAHj4cs9Ax1=CoJkgBGP_+sNu6-6=6v=_L-ZBZY0bVLD3wUWZQg@mail.gmail.com
Reported-by: Alison Schofield <alison.schofield@intel.com>
Closes: https://lore.kernel.org/linux-mm/Zq0tPd2h6alFz8XF@aschofie-mobl2/#t
Fixes: 15995a352474 ("mm: report per-page metadata information")
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Tested-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: Alison Schofield <alison.schofield@intel.com>
Acked-by: David Hildenbrand <david@redhat.com>
---
include/linux/mmzone.h | 2 --
include/linux/vmstat.h | 7 ++++---
mm/hugetlb_vmemmap.c | 8 ++++----
mm/mm_init.c | 3 +--
mm/page_alloc.c | 1 -
mm/page_ext.c | 18 ++++-------------
mm/sparse-vmemmap.c | 11 ++++------
mm/sparse.c | 5 ++---
mm/vmstat.c | 46 ++++++++++++++++++++----------------------
9 files changed, 41 insertions(+), 60 deletions(-)
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 41458892bc8a..1dc6248feb83 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -220,8 +220,6 @@ enum node_stat_item {
PGDEMOTE_KSWAPD,
PGDEMOTE_DIRECT,
PGDEMOTE_KHUGEPAGED,
- NR_MEMMAP, /* page metadata allocated through buddy allocator */
- NR_MEMMAP_BOOT, /* page metadata allocated through boot allocator */
NR_VM_NODE_STAT_ITEMS
};
diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h
index 9ab4fa5e09b5..9eb77c9007e6 100644
--- a/include/linux/vmstat.h
+++ b/include/linux/vmstat.h
@@ -38,6 +38,8 @@ struct reclaim_stat {
enum vm_stat_item {
NR_DIRTY_THRESHOLD,
NR_DIRTY_BG_THRESHOLD,
+ NR_MEMMAP_PAGES, /* page metadata allocated through buddy allocator */
+ NR_MEMMAP_BOOT_PAGES, /* page metadata allocated through boot allocator */
NR_VM_STAT_ITEMS,
};
@@ -618,7 +620,6 @@ static inline void lruvec_stat_sub_folio(struct folio *folio,
lruvec_stat_mod_folio(folio, idx, -folio_nr_pages(folio));
}
-void __meminit mod_node_early_perpage_metadata(int nid, long delta);
-void __meminit store_early_perpage_metadata(void);
-
+void memmap_boot_pages_add(long delta);
+void memmap_pages_add(long delta);
#endif /* _LINUX_VMSTAT_H */
diff --git a/mm/hugetlb_vmemmap.c b/mm/hugetlb_vmemmap.c
index 4f51e0596197..0c3f56b3578e 100644
--- a/mm/hugetlb_vmemmap.c
+++ b/mm/hugetlb_vmemmap.c
@@ -185,11 +185,11 @@ static int vmemmap_remap_range(unsigned long start, unsigned long end,
static inline void free_vmemmap_page(struct page *page)
{
if (PageReserved(page)) {
+ memmap_boot_pages_add(-1);
free_bootmem_page(page);
- mod_node_page_state(page_pgdat(page), NR_MEMMAP_BOOT, -1);
} else {
+ memmap_pages_add(-1);
__free_page(page);
- mod_node_page_state(page_pgdat(page), NR_MEMMAP, -1);
}
}
@@ -341,7 +341,7 @@ static int vmemmap_remap_free(unsigned long start, unsigned long end,
copy_page(page_to_virt(walk.reuse_page),
(void *)walk.reuse_addr);
list_add(&walk.reuse_page->lru, vmemmap_pages);
- mod_node_page_state(NODE_DATA(nid), NR_MEMMAP, 1);
+ memmap_pages_add(1);
}
/*
@@ -396,7 +396,7 @@ static int alloc_vmemmap_page_list(unsigned long start, unsigned long end,
goto out;
list_add(&page->lru, list);
}
- mod_node_page_state(NODE_DATA(nid), NR_MEMMAP, nr_pages);
+ memmap_pages_add(nr_pages);
return 0;
out:
diff --git a/mm/mm_init.c b/mm/mm_init.c
index 75c3bd42799b..f9a60ffc5532 100644
--- a/mm/mm_init.c
+++ b/mm/mm_init.c
@@ -1623,8 +1623,7 @@ static void __init alloc_node_mem_map(struct pglist_data *pgdat)
panic("Failed to allocate %ld bytes for node %d memory map\n",
size, pgdat->node_id);
pgdat->node_mem_map = map + offset;
- mod_node_early_perpage_metadata(pgdat->node_id,
- DIV_ROUND_UP(size, PAGE_SIZE));
+ memmap_boot_pages_add(DIV_ROUND_UP(size, PAGE_SIZE));
pr_debug("%s: node %d, pgdat %08lx, node_mem_map %08lx\n",
__func__, pgdat->node_id, (unsigned long)pgdat,
(unsigned long)pgdat->node_mem_map);
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 28f80daf5c04..875d76e8684a 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5755,7 +5755,6 @@ void __init setup_per_cpu_pageset(void)
for_each_online_pgdat(pgdat)
pgdat->per_cpu_nodestats =
alloc_percpu(struct per_cpu_nodestat);
- store_early_perpage_metadata();
}
__meminit void zone_pcp_init(struct zone *zone)
diff --git a/mm/page_ext.c b/mm/page_ext.c
index c191e490c401..641d93f6af4c 100644
--- a/mm/page_ext.c
+++ b/mm/page_ext.c
@@ -214,8 +214,7 @@ static int __init alloc_node_page_ext(int nid)
return -ENOMEM;
NODE_DATA(nid)->node_page_ext = base;
total_usage += table_size;
- mod_node_page_state(NODE_DATA(nid), NR_MEMMAP_BOOT,
- DIV_ROUND_UP(table_size, PAGE_SIZE));
+ memmap_boot_pages_add(DIV_ROUND_UP(table_size, PAGE_SIZE));
return 0;
}
@@ -275,10 +274,8 @@ static void *__meminit alloc_page_ext(size_t size, int nid)
else
addr = vzalloc_node(size, nid);
- if (addr) {
- mod_node_page_state(NODE_DATA(nid), NR_MEMMAP,
- DIV_ROUND_UP(size, PAGE_SIZE));
- }
+ if (addr)
+ memmap_pages_add(DIV_ROUND_UP(size, PAGE_SIZE));
return addr;
}
@@ -323,25 +320,18 @@ static void free_page_ext(void *addr)
{
size_t table_size;
struct page *page;
- struct pglist_data *pgdat;
table_size = page_ext_size * PAGES_PER_SECTION;
+ memmap_pages_add(-1L * (DIV_ROUND_UP(table_size, PAGE_SIZE)));
if (is_vmalloc_addr(addr)) {
- page = vmalloc_to_page(addr);
- pgdat = page_pgdat(page);
vfree(addr);
} else {
page = virt_to_page(addr);
- pgdat = page_pgdat(page);
BUG_ON(PageReserved(page));
kmemleak_free(addr);
free_pages_exact(addr, table_size);
}
-
- mod_node_page_state(pgdat, NR_MEMMAP,
- -1L * (DIV_ROUND_UP(table_size, PAGE_SIZE)));
-
}
static void __free_page_ext(unsigned long pfn)
diff --git a/mm/sparse-vmemmap.c b/mm/sparse-vmemmap.c
index 1dda6c53370b..edcc7a6b0f6f 100644
--- a/mm/sparse-vmemmap.c
+++ b/mm/sparse-vmemmap.c
@@ -469,13 +469,10 @@ struct page * __meminit __populate_section_memmap(unsigned long pfn,
if (r < 0)
return NULL;
- if (system_state == SYSTEM_BOOTING) {
- mod_node_early_perpage_metadata(nid, DIV_ROUND_UP(end - start,
- PAGE_SIZE));
- } else {
- mod_node_page_state(NODE_DATA(nid), NR_MEMMAP,
- DIV_ROUND_UP(end - start, PAGE_SIZE));
- }
+ if (system_state == SYSTEM_BOOTING)
+ memmap_boot_pages_add(DIV_ROUND_UP(end - start, PAGE_SIZE));
+ else
+ memmap_pages_add(DIV_ROUND_UP(end - start, PAGE_SIZE));
return pfn_to_page(pfn);
}
diff --git a/mm/sparse.c b/mm/sparse.c
index e4b830091d13..0f018c6f9ec5 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -463,7 +463,7 @@ static void __init sparse_buffer_init(unsigned long size, int nid)
sparsemap_buf = memmap_alloc(size, section_map_size(), addr, nid, true);
sparsemap_buf_end = sparsemap_buf + size;
#ifndef CONFIG_SPARSEMEM_VMEMMAP
- mod_node_early_perpage_metadata(nid, DIV_ROUND_UP(size, PAGE_SIZE));
+ memmap_boot_pages_add(DIV_ROUND_UP(size, PAGE_SIZE));
#endif
}
@@ -643,8 +643,7 @@ static void depopulate_section_memmap(unsigned long pfn, unsigned long nr_pages,
unsigned long start = (unsigned long) pfn_to_page(pfn);
unsigned long end = start + nr_pages * sizeof(struct page);
- mod_node_page_state(page_pgdat(pfn_to_page(pfn)), NR_MEMMAP,
- -1L * (DIV_ROUND_UP(end - start, PAGE_SIZE)));
+ memmap_pages_add(-1L * (DIV_ROUND_UP(end - start, PAGE_SIZE)));
vmemmap_free(start, end, altmap);
}
static void free_map_bootmem(struct page *memmap)
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 6f8aa4766f16..e875f2a4915f 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -1033,6 +1033,24 @@ unsigned long node_page_state(struct pglist_data *pgdat,
}
#endif
+/*
+ * Count number of pages "struct page" and "struct page_ext" consume.
+ * nr_memmap_boot_pages: # of pages allocated by boot allocator
+ * nr_memmap_pages: # of pages that were allocated by buddy allocator
+ */
+static atomic_long_t nr_memmap_boot_pages = ATOMIC_LONG_INIT(0);
+static atomic_long_t nr_memmap_pages = ATOMIC_LONG_INIT(0);
+
+void memmap_boot_pages_add(long delta)
+{
+ atomic_long_add(delta, &nr_memmap_boot_pages);
+}
+
+void memmap_pages_add(long delta)
+{
+ atomic_long_add(delta, &nr_memmap_pages);
+}
+
#ifdef CONFIG_COMPACTION
struct contig_page_info {
@@ -1255,11 +1273,11 @@ const char * const vmstat_text[] = {
"pgdemote_kswapd",
"pgdemote_direct",
"pgdemote_khugepaged",
- "nr_memmap",
- "nr_memmap_boot",
/* system-wide enum vm_stat_item counters */
"nr_dirty_threshold",
"nr_dirty_background_threshold",
+ "nr_memmap_pages",
+ "nr_memmap_boot_pages",
#if defined(CONFIG_VM_EVENT_COUNTERS) || defined(CONFIG_MEMCG)
/* enum vm_event_item counters */
@@ -1827,6 +1845,8 @@ static void *vmstat_start(struct seq_file *m, loff_t *pos)
global_dirty_limits(v + NR_DIRTY_BG_THRESHOLD,
v + NR_DIRTY_THRESHOLD);
+ v[NR_MEMMAP_PAGES] = atomic_long_read(&nr_memmap_pages);
+ v[NR_MEMMAP_BOOT_PAGES] = atomic_long_read(&nr_memmap_boot_pages);
v += NR_VM_STAT_ITEMS;
#ifdef CONFIG_VM_EVENT_COUNTERS
@@ -2285,25 +2305,3 @@ static int __init extfrag_debug_init(void)
module_init(extfrag_debug_init);
#endif
-
-/*
- * Page metadata size (struct page and page_ext) in pages
- */
-static unsigned long early_perpage_metadata[MAX_NUMNODES] __meminitdata;
-
-void __meminit mod_node_early_perpage_metadata(int nid, long delta)
-{
- early_perpage_metadata[nid] += delta;
-}
-
-void __meminit store_early_perpage_metadata(void)
-{
- int nid;
- struct pglist_data *pgdat;
-
- for_each_online_pgdat(pgdat) {
- nid = pgdat->node_id;
- mod_node_page_state(NODE_DATA(nid), NR_MEMMAP_BOOT,
- early_perpage_metadata[nid]);
- }
-}
--
2.46.0.76.ge559c4bf1a-goog
^ permalink raw reply [flat|nested] 9+ messages in thread