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>
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 243f4cc..f60c4eb 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -820,17 +820,19 @@
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 @@
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 @@
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 @@
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