Kernel/linux-next
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git synced 2024-12-29 09:12:07 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

mm/page_owner: record timestamp and pid

Browse Source 
Collect the time for each allocation recorded in page owner so that
allocation "surges" can be measured.

Record the pid for each allocation recorded in page owner so that the
source of allocation "surges" can be better identified.

The above is very useful when doing memory analysis.  On a crash for
example, we can get this information from kdump (or ramdump) and parse it
to figure out memory allocation problems.

Please note that on x86_64 this increases the size of struct page_owner
from 16 bytes to 32.

Vlastimil: it's not a functionality intended for production, so unless
somebody says they need to enable page_owner for debugging and this
increase prevents them from fitting into available memory, let's not
complicate things with making this optional.

[lmark@codeaurora.org: v3]
  Link: https://lkml.kernel.org/r/20201210160357.27779-1-georgi.djakov@linaro.org

Link: https://lkml.kernel.org/r/20201209125153.10533-1-georgi.djakov@linaro.org
Signed-off-by: Liam Mark <lmark@codeaurora.org>
Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Liam Mark 2020-12-14 19:04:49 -08:00 committed by Linus Torvalds
parent 7fb7ab6d61
commit 9cc7e96aa8
2 changed files with 19 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
Documentation/vm/page_owner.rst
View File

@ -41,17 +41,17 @@ size change due to this facility.
- Without page owner::
text data bss dec hex filename
40662 1493 644 42799 a72f mm/page_alloc.o
48392 2333 644 51369 c8a9 mm/page_alloc.o
- With page owner::
text data bss dec hex filename
40892 1493 644 43029 a815 mm/page_alloc.o
1427 24 8 1459 5b3 mm/page_ext.o
2722 50 0 2772 ad4 mm/page_owner.o
48800 2445 644 51889 cab1 mm/page_alloc.o
6574 108 29 6711 1a37 mm/page_owner.o
1025 8 8 1041 411 mm/page_ext.o
Although, roughly, 4 KB code is added in total, page_alloc.o increase by
230 bytes and only half of it is in hotpath. Building the kernel with
Although, roughly, 8 KB code is added in total, page_alloc.o increase by
520 bytes and less than half of it is in hotpath. Building the kernel with
page owner and turning it on if needed would be great option to debug
kernel memory problem.

17
mm/page_owner.c
View File

@ -10,6 +10,7 @@
#include <linux/migrate.h>
#include <linux/stackdepot.h>
#include <linux/seq_file.h>
#include <linux/sched/clock.h>
#include "internal.h"
@ -25,6 +26,8 @@ struct page_owner {
gfp_t gfp_mask;
depot_stack_handle_t handle;
depot_stack_handle_t free_handle;
u64 ts_nsec;
pid_t pid;
};
static bool page_owner_enabled = false;
@ -172,6 +175,8 @@ static inline void __set_page_owner_handle(struct page *page,
page_owner->order = order;
page_owner->gfp_mask = gfp_mask;
page_owner->last_migrate_reason = -1;
page_owner->pid = current->pid;
page_owner->ts_nsec = local_clock();
__set_bit(PAGE_EXT_OWNER, &page_ext->flags);
__set_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags);
@ -236,6 +241,8 @@ void __copy_page_owner(struct page *oldpage, struct page *newpage)
new_page_owner->last_migrate_reason =
old_page_owner->last_migrate_reason;
new_page_owner->handle = old_page_owner->handle;
new_page_owner->pid = old_page_owner->pid;
new_page_owner->ts_nsec = old_page_owner->ts_nsec;
/*
* We don't clear the bit on the oldpage as it's going to be freed
@ -349,9 +356,10 @@ print_page_owner(char __user *buf, size_t count, unsigned long pfn,
return -ENOMEM;
ret = snprintf(kbuf, count,
"Page allocated via order %u, mask %#x(%pGg)\n",
"Page allocated via order %u, mask %#x(%pGg), pid %d, ts %llu ns\n",
page_owner->order, page_owner->gfp_mask,
&page_owner->gfp_mask);
&page_owner->gfp_mask, page_owner->pid,
page_owner->ts_nsec);
if (ret >= count)
goto err;
@ -427,8 +435,9 @@ void __dump_page_owner(struct page *page)
else
pr_alert("page_owner tracks the page as freed\n");
pr_alert("page last allocated via order %u, migratetype %s, gfp_mask %#x(%pGg)\n",
page_owner->order, migratetype_names[mt], gfp_mask, &gfp_mask);
pr_alert("page last allocated via order %u, migratetype %s, gfp_mask %#x(%pGg), pid %d, ts %llu\n",
page_owner->order, migratetype_names[mt], gfp_mask, &gfp_mask,
page_owner->pid, page_owner->ts_nsec);
handle = READ_ONCE(page_owner->handle);
if (!handle) {