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Commit 17766dde364813568e4f876517c72bab70838646

Authored by David Rientjes
Committed by Linus Torvalds
1 parent c02925540c
Exists in smarc-imx_3.14.28_1.0.0_ga and in 1 other branch imx_3.14.28_1.0.0_ga

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: David 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Showing 1 changed file with 7 additions and 3 deletions Side-by-side Diff

... ... @@ -820,17 +820,19 @@
820 820 count_vm_event(THP_FAULT_FALLBACK);
821 821 return VM_FAULT_FALLBACK;
822 822 }
823   - count_vm_event(THP_FAULT_ALLOC);
824 823 if (unlikely(mem_cgroup_newpage_charge(page, mm, GFP_KERNEL))) {
825 824 put_page(page);
  825 + count_vm_event(THP_FAULT_FALLBACK);
826 826 return VM_FAULT_FALLBACK;
827 827 }
828 828 if (unlikely(__do_huge_pmd_anonymous_page(mm, vma, haddr, pmd, page))) {
829 829 mem_cgroup_uncharge_page(page);
830 830 put_page(page);
  831 + count_vm_event(THP_FAULT_FALLBACK);
831 832 return VM_FAULT_FALLBACK;
832 833 }
833 834  
  835 + count_vm_event(THP_FAULT_ALLOC);
834 836 return 0;
835 837 }
836 838  
... ... @@ -1143,7 +1145,6 @@
1143 1145 new_page = NULL;
1144 1146  
1145 1147 if (unlikely(!new_page)) {
1146   - count_vm_event(THP_FAULT_FALLBACK);
1147 1148 if (is_huge_zero_pmd(orig_pmd)) {
1148 1149 ret = do_huge_pmd_wp_zero_page_fallback(mm, vma,
1149 1150 address, pmd, orig_pmd, haddr);
1150 1151  
... ... @@ -1154,9 +1155,9 @@
1154 1155 split_huge_page(page);
1155 1156 put_page(page);
1156 1157 }
  1158 + count_vm_event(THP_FAULT_FALLBACK);
1157 1159 goto out;
1158 1160 }
1159   - count_vm_event(THP_FAULT_ALLOC);
1160 1161  
1161 1162 if (unlikely(mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))) {
1162 1163 put_page(new_page);
1163 1164  
... ... @@ -1164,9 +1165,12 @@
1164 1165 split_huge_page(page);
1165 1166 put_page(page);
1166 1167 }
  1168 + count_vm_event(THP_FAULT_FALLBACK);
1167 1169 ret |= VM_FAULT_OOM;
1168 1170 goto out;
1169 1171 }
  1172 +
  1173 + count_vm_event(THP_FAULT_ALLOC);
1170 1174  
1171 1175 if (is_huge_zero_pmd(orig_pmd))
1172 1176 clear_huge_page(new_page, haddr, HPAGE_PMD_NR);