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mm: memcg: add THP swap out info for anonymous reclaim

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At present, we support per-memcg reclaim strategy, however we do not know
the number of transparent huge pages being reclaimed, as we know the
transparent huge pages need to be splited before reclaim them, and they
will bring some performance bottleneck effect.  for example, when two
memcg (A & B) are doing reclaim for anonymous pages at same time, and 'A'
memcg is reclaiming a large number of transparent huge pages, we can
better analyze that the performance bottleneck will be caused by 'A'
memcg.  therefore, in order to better analyze such problems, there add THP
swap out info for per-memcg.

[akpm@linux-foundation.orgL fix swap_writepage_fs(), per Johannes]
  Link: https://lkml.kernel.org/r/20230913213343.GB48476@cmpxchg.org
Link: https://lkml.kernel.org/r/20230913164938.16918-1-vernhao@tencent.com
Signed-off-by: Xin Hao <vernhao@tencent.com>
Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Xin Hao 2023-09-14 00:49:37 +08:00 committed by Andrew Morton
parent ed547ab6f4
commit 811244a501
4 changed files with 16 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
Documentation/admin-guide/cgroup-v2.rst
View File

@ -1532,6 +1532,15 @@ PAGE_SIZE multiple when read back.
collapsing an existing range of pages. This counter is not
present when CONFIG_TRANSPARENT_HUGEPAGE is not set.
thp_swpout (npn)
Number of transparent hugepages which are swapout in one piece
without splitting.
thp_swpout_fallback (npn)
Number of transparent hugepages which were split before swapout.
Usually because failed to allocate some continuous swap space
for the huge page.
memory.numa_stat
A read-only nested-keyed file which exists on non-root cgroups.

2
mm/memcontrol.c
View File

@ -704,6 +704,8 @@ static const unsigned int memcg_vm_event_stat[] = {
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
THP_FAULT_ALLOC,
THP_COLLAPSE_ALLOC,
THP_SWPOUT,
THP_SWPOUT_FALLBACK,
#endif
};

8
mm/page_io.c
View File

@ -208,8 +208,10 @@ int swap_writepage(struct page *page, struct writeback_control *wbc)
static inline void count_swpout_vm_event(struct folio *folio)
{
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
if (unlikely(folio_test_pmd_mappable(folio)))
if (unlikely(folio_test_pmd_mappable(folio))) {
count_memcg_folio_events(folio, THP_SWPOUT, 1);
count_vm_event(THP_SWPOUT);
}
#endif
count_vm_events(PSWPOUT, folio_nr_pages(folio));
}
@ -278,9 +280,6 @@ static void sio_write_complete(struct kiocb *iocb, long ret)
set_page_dirty(page);
ClearPageReclaim(page);
}
} else {
for (p = 0; p < sio->pages; p++)
count_swpout_vm_event(page_folio(sio->bvec[p].bv_page));
}
for (p = 0; p < sio->pages; p++)
@ -296,6 +295,7 @@ static void swap_writepage_fs(struct page *page, struct writeback_control *wbc)
struct file *swap_file = sis->swap_file;
loff_t pos = page_file_offset(page);
count_swpout_vm_event(page_folio(page));
set_page_writeback(page);
unlock_page(page);
if (wbc->swap_plug)

1
mm/vmscan.c
View File

@ -1214,6 +1214,7 @@ retry:
folio_list))
goto activate_locked;
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
count_memcg_folio_events(folio, THP_SWPOUT_FALLBACK, 1);
count_vm_event(THP_SWPOUT_FALLBACK);
#endif
if (!add_to_swap(folio))