6.6-stable review patch. If anyone has any objections, please let me know.
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From: Xin Hao vernhao@tencent.com
[ Upstream commit 811244a501b967b00fecb1ae906d5dc6329c91e0 ]
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 Signed-off-by: Leon Huang Fu leon.huangfu@shopee.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- Documentation/admin-guide/cgroup-v2.rst | 9 +++++++++ mm/memcontrol.c | 2 ++ mm/page_io.c | 8 ++++---- mm/vmscan.c | 1 + 4 files changed, 16 insertions(+), 4 deletions(-)
--- a/Documentation/admin-guide/cgroup-v2.rst +++ b/Documentation/admin-guide/cgroup-v2.rst @@ -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.
--- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -704,6 +704,8 @@ static const unsigned int memcg_vm_event #ifdef CONFIG_TRANSPARENT_HUGEPAGE THP_FAULT_ALLOC, THP_COLLAPSE_ALLOC, + THP_SWPOUT, + THP_SWPOUT_FALLBACK, #endif };
--- a/mm/page_io.c +++ b/mm/page_io.c @@ -208,8 +208,10 @@ int swap_writepage(struct page *page, st 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 ki 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 pag 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) --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1922,6 +1922,7 @@ 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))