From 85b9f46e8ea451633ccd60a7d8cacbfff9f34047 Mon Sep 17 00:00:00 2001 From: David Rientjes Date: Mon, 6 Apr 2020 20:04:28 -0700 Subject: mm, thp: track fallbacks due to failed memcg charges separately The thp_fault_fallback and thp_file_fallback vmstats are incremented if either the hugepage allocation fails through the page allocator or the hugepage charge fails through mem cgroup. This patch leaves this field untouched but adds two new fields, thp_{fault,file}_fallback_charge, which is incremented only when the mem cgroup charge fails. This distinguishes between attempted hugepage allocations that fail due to fragmentation (or low memory conditions) and those that fail due to mem cgroup limits. That can be used to determine the impact of fragmentation on the system by excluding faults that failed due to memcg usage. Signed-off-by: David Rientjes Signed-off-by: Andrew Morton Reviewed-by: Yang Shi Acked-by: Kirill A. Shutemov Cc: Mike Rapoport Cc: Jeremy Cline Cc: Andrea Arcangeli Cc: Mike Kravetz Cc: Michal Hocko Cc: Vlastimil Babka Link: http://lkml.kernel.org/r/alpine.DEB.2.21.2003061422070.7412@chino.kir.corp.google.com Signed-off-by: Linus Torvalds --- mm/shmem.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'mm/shmem.c') diff --git a/mm/shmem.c b/mm/shmem.c index 8160d0762bf5..b48ac3806f8f 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1871,8 +1871,10 @@ alloc_nohuge: error = mem_cgroup_try_charge_delay(page, charge_mm, gfp, &memcg, PageTransHuge(page)); if (error) { - if (PageTransHuge(page)) + if (PageTransHuge(page)) { count_vm_event(THP_FILE_FALLBACK); + count_vm_event(THP_FILE_FALLBACK_CHARGE); + } goto unacct; } error = shmem_add_to_page_cache(page, mapping, hindex, -- cgit v1.2.3