When do_swap_page returns VM_FAULT_RETRY, we do not retry here and thus
swap entry will remain in pagetable. This will result in later failure.
So stop swapping in pages in this case to save cpu cycles.
Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
---
mm/khugepaged.c | 19 ++++++++-----------
1 file changed, 8 insertions(+), 11 deletions(-)
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 73570dfffcec..a8adb2d1e9c6 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -1003,19 +1003,16 @@ static bool __collapse_huge_page_swapin(struct mm_struct *mm,
swapped_in++;
ret = do_swap_page(&vmf);
- /* do_swap_page returns VM_FAULT_RETRY with released mmap_lock */
+ /*
+ * do_swap_page returns VM_FAULT_RETRY with released mmap_lock.
+ * Note we treat VM_FAULT_RETRY as VM_FAULT_ERROR here because
+ * we do not retry here and swap entry will remain in pagetable
+ * resulting in later failure.
+ */
if (ret & VM_FAULT_RETRY) {
mmap_read_lock(mm);
- if (hugepage_vma_revalidate(mm, haddr, &vma)) {
- /* vma is no longer available, don't continue to swapin */
- trace_mm_collapse_huge_page_swapin(mm, swapped_in, referenced, 0);
- return false;
- }
- /* check if the pmd is still valid */
- if (mm_find_pmd(mm, haddr) != pmd) {
- trace_mm_collapse_huge_page_swapin(mm, swapped_in, referenced, 0);
- return false;
- }
+ trace_mm_collapse_huge_page_swapin(mm, swapped_in, referenced, 0);
+ return false;
}
if (ret & VM_FAULT_ERROR) {
trace_mm_collapse_huge_page_swapin(mm, swapped_in, referenced, 0);
--
2.23.0
