Merge tag 'mm-hotfixes-stable-2022-09-26' of git://git.kernel.org/pub/scm/linux/kerne...

[people/ms/linux.git] / mm / khugepaged.c

diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 01f71786d530353c2c9a14adaf068c13cb204f83..70b7ac66411c00202363189a6209739ea455bc03 100644 (file)
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -1083,10 +1083,12 @@ static void collapse_huge_page(struct mm_struct *mm,
 
        pmd_ptl = pmd_lock(mm, pmd); /* probably unnecessary */
        /*
-        * After this gup_fast can't run anymore. This also removes
-        * any huge TLB entry from the CPU so we won't allow
-        * huge and small TLB entries for the same virtual address
-        * to avoid the risk of CPU bugs in that area.
+        * This removes any huge TLB entry from the CPU so we won't allow
+        * huge and small TLB entries for the same virtual address to
+        * avoid the risk of CPU bugs in that area.
+        *
+        * Parallel fast GUP is fine since fast GUP will back off when
+        * it detects PMD is changed.
         */
        _pmd = pmdp_collapse_flush(vma, address, pmd);
        spin_unlock(pmd_ptl);