The patch titled
Subject: mm/page_owner: remove free_ts from page_owner output
has been added to the -mm mm-unstable branch. Its filename is
mm-page_owner-remove-free_ts-from-page_owner-output.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-page_owner-remove-free_ts-from-page_owner-output.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Audra Mitchell <audra@xxxxxxxxxx>
Subject: mm/page_owner: remove free_ts from page_owner output
Date: Fri, 13 Oct 2023 15:03:45 -0400
Patch series "Fix page_owner's use of free timestamps".
While page ower output is used to investigate memory utilization,
typically the allocation pathway, the introduction of timestamps to the
page owner records caused each record to become unique due to the
granularity of the nanosecond timestamp (for example):
Page allocated via order 0 ... ts 5206196026 ns, free_ts 5187156703 ns
Page allocated via order 0 ... ts 5206198540 ns, free_ts 5187162702 ns
Furthermore, the page_owner output only dumps the currently allocated
records, so having the free timestamps is nonsensical for the typical use
case.
In addition, the introduction of timestamps was not properly handled in
the page_owner_sort tool causing most use cases to be broken. This series
is meant to remove the free timestamps from the page_owner output and fix
the page_owner_sort tool so proper collation can occur.
This patch (of 5):
When printing page_owner data via the sysfs interface, no free pages will
ever be dumped due to the series of checks in read_page_owner():
/*
* Although we do have the info about past allocation of free
* pages, it's not relevant for current memory usage.
*/
if (!test_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags))
The free_ts values are still used when dump_page_owner() is called, so
keeping the field for other use cases but removing them for the typical
page_owner case.
Link: https://lkml.kernel.org/r/20231013190350.579407-1-audra@xxxxxxxxxx
Link: https://lkml.kernel.org/r/20231013190350.579407-2-audra@xxxxxxxxxx
Fixes: 866b48526217 ("mm/page_owner: record the timestamp of all pages during free")
Signed-off-by: Audra Mitchell <audra@xxxxxxxxxx>
Cc: Georgi Djakov <djakov@xxxxxxxxxx>
Cc: Rafael Aquini <raquini@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page_owner.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/mm/page_owner.c~mm-page_owner-remove-free_ts-from-page_owner-output
+++ a/mm/page_owner.c
@@ -408,11 +408,11 @@ print_page_owner(char __user *buf, size_
return -ENOMEM;
ret = scnprintf(kbuf, count,
- "Page allocated via order %u, mask %#x(%pGg), pid %d, tgid %d (%s), ts %llu ns, free_ts %llu ns\n",
+ "Page allocated via order %u, mask %#x(%pGg), pid %d, tgid %d (%s), ts %llu ns\n",
page_owner->order, page_owner->gfp_mask,
&page_owner->gfp_mask, page_owner->pid,
page_owner->tgid, page_owner->comm,
- page_owner->ts_nsec, page_owner->free_ts_nsec);
+ page_owner->ts_nsec);
/* Print information relevant to grouping pages by mobility */
pageblock_mt = get_pageblock_migratetype(page);
_
Patches currently in -mm which might be from audra@xxxxxxxxxx are
mm-page_owner-remove-free_ts-from-page_owner-output.patch
tools-mm-remove-references-to-free_ts-from-page_owner_sort.patch
tools-mm-filter-out-timestamps-for-correct-collation.patch
tools-mm-fix-the-default-case-for-page_owner_sort.patch
tools-mm-update-the-usage-output-to-be-more-organized.patch
