Currently, thp_fault_fallback in vmstat only gets incremented if a hugepage allocation fails. If current's memcg hits its limit or the page fault handler returns an error, it is incorrectly accounted as a successful thp_fault_alloc.
Count thp_fault_fallback anytime the page fault handler falls back to using regular pages and only count thp_fault_alloc when a hugepage has actually been faulted. Signed-off-by: David Rientjes <[email protected]> --- mm/huge_memory.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -801,7 +801,6 @@ int do_huge_pmd_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma, zero_page = get_huge_zero_page(); if (unlikely(!zero_page)) { pte_free(mm, pgtable); - count_vm_event(THP_FAULT_FALLBACK); goto out; } spin_lock(&mm->page_table_lock); @@ -816,11 +815,8 @@ int do_huge_pmd_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma, } page = alloc_hugepage_vma(transparent_hugepage_defrag(vma), vma, haddr, numa_node_id(), 0); - if (unlikely(!page)) { - count_vm_event(THP_FAULT_FALLBACK); + if (unlikely(!page)) goto out; - } - count_vm_event(THP_FAULT_ALLOC); if (unlikely(mem_cgroup_newpage_charge(page, mm, GFP_KERNEL))) { put_page(page); goto out; @@ -832,9 +828,11 @@ int do_huge_pmd_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma, goto out; } + count_vm_event(THP_FAULT_ALLOC); return 0; } out: + count_vm_event(THP_FAULT_FALLBACK); /* * Use __pte_alloc instead of pte_alloc_map, because we can't * run pte_offset_map on the pmd, if an huge pmd could -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
