Messages in this thread | | | From | "Kirill A. Shutemov" <> | Subject | RE: [patch] mm, thp: count thp_fault_fallback anytime thp fault fails | Date | Wed, 21 Aug 2013 17:28:17 +0300 (EEST) |
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David Rientjes wrote: > 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 <rientjes@google.com>
It's probably a good idea, but please make the behaviour consistent in do_huge_pmd_wp_page() and collapse path, otherwise it doesn't make sense.
And please make the patch against mm tree: do_huge_pmd_anonymous_page() was modified recently.
> --- > 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
-- Kirill A. Shutemov
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