diff options
Diffstat (limited to 'mm/khugepaged.c')
| -rw-r--r-- | mm/khugepaged.c | 11 |
1 files changed, 2 insertions, 9 deletions
diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 9c111273bbf91f..0d8f548d9d7ed6 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1238,15 +1238,8 @@ static int hpage_collapse_scan_pmd(struct mm_struct *mm, /* * Check if the page has any GUP (or other external) pins. * - * Here the check is racy it may see total_mapcount > refcount - * in some cases. - * For example, one process with one forked child process. - * The parent has the PMD split due to MADV_DONTNEED, then - * the child is trying unmap the whole PMD, but khugepaged - * may be scanning the parent between the child has - * PageDoubleMap flag cleared and dec the mapcount. So - * khugepaged may see total_mapcount > refcount. - * + * Here the check may be racy: + * it may see total_mapcount > refcount in some cases? * But such case is ephemeral we could always retry collapse * later. However it may report false positive if the page * has excessive GUP pins (i.e. 512). Anyway the same check |