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@xxxxxxxxxx>
---
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
--
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