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Commit 17766dde authored by David Rientjes's avatar David Rientjes Committed by Linus Torvalds
Browse files

mm, thp: count thp_fault_fallback anytime thp fault fails 



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: default avatarDavid Rientjes <rientjes@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent c0292554

mm/huge_memory.c

+7 −3
Original line number Diff line number Diff line
@@ -820,17 +820,19 @@ int do_huge_pmd_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma, 
		count_vm_event(THP_FAULT_FALLBACK);

		return VM_FAULT_FALLBACK;

	}

	count_vm_event(THP_FAULT_ALLOC);

	if (unlikely(mem_cgroup_newpage_charge(page, mm, GFP_KERNEL))) {

		put_page(page);

		count_vm_event(THP_FAULT_FALLBACK);

		return VM_FAULT_FALLBACK;

	}

	if (unlikely(__do_huge_pmd_anonymous_page(mm, vma, haddr, pmd, page))) {

		mem_cgroup_uncharge_page(page);

		put_page(page);

		count_vm_event(THP_FAULT_FALLBACK);

		return VM_FAULT_FALLBACK;

	}



	count_vm_event(THP_FAULT_ALLOC);

	return 0;

}
@@ -1143,7 +1145,6 @@ int do_huge_pmd_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, 
		new_page = NULL;



	if (unlikely(!new_page)) {

		count_vm_event(THP_FAULT_FALLBACK);

		if (is_huge_zero_pmd(orig_pmd)) {

			ret = do_huge_pmd_wp_zero_page_fallback(mm, vma,

					address, pmd, orig_pmd, haddr);
@@ -1154,9 +1155,9 @@ int do_huge_pmd_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, 
				split_huge_page(page);

			put_page(page);

		}

		count_vm_event(THP_FAULT_FALLBACK);

		goto out;

	}

	count_vm_event(THP_FAULT_ALLOC);



	if (unlikely(mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))) {

		put_page(new_page);
@@ -1164,10 +1165,13 @@ int do_huge_pmd_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, 
			split_huge_page(page);

			put_page(page);

		}

		count_vm_event(THP_FAULT_FALLBACK);

		ret |= VM_FAULT_OOM;

		goto out;

	}



	count_vm_event(THP_FAULT_ALLOC);



	if (is_huge_zero_pmd(orig_pmd))

		clear_huge_page(new_page, haddr, HPAGE_PMD_NR);

	else