The patch titled
Subject: mm, thp: copying user pages must schedule on collapse
has been added to the -mm tree. Its filename is
mm-thp-copying-user-pages-must-schedule-on-collapse.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-thp-copying-user-pages-must-schedule-on-collapse.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-thp-copying-user-pages-must-schedule-on-collapse.patch
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------------------------------------------------------
From: David Rientjes <rientjes@xxxxxxxxxx>
Subject: mm, thp: copying user pages must schedule on collapse
We have encountered need_resched warnings in __collapse_huge_page_copy()
while doing {clear,copy}_user_highpage() over HPAGE_PMD_NR source pages.
mm->mmap_sem is held for write, but the iteration is well bounded.
Reschedule as needed.
Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1705101426380.109808@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx>
Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/khugepaged.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
diff -puN mm/khugepaged.c~mm-thp-copying-user-pages-must-schedule-on-collapse mm/khugepaged.c
--- a/mm/khugepaged.c~mm-thp-copying-user-pages-must-schedule-on-collapse
+++ a/mm/khugepaged.c
@@ -612,7 +612,8 @@ static void __collapse_huge_page_copy(pt
spinlock_t *ptl)
{
pte_t *_pte;
- for (_pte = pte; _pte < pte+HPAGE_PMD_NR; _pte++) {
+ for (_pte = pte; _pte < pte + HPAGE_PMD_NR;
+ _pte++, page++, address += PAGE_SIZE) {
pte_t pteval = *_pte;
struct page *src_page;
@@ -651,9 +652,7 @@ static void __collapse_huge_page_copy(pt
spin_unlock(ptl);
free_page_and_swap_cache(src_page);
}
-
- address += PAGE_SIZE;
- page++;
+ cond_resched();
}
}
_
Patches currently in -mm which might be from rientjes@xxxxxxxxxx are
mm-thp-copying-user-pages-must-schedule-on-collapse.patch
fs-epoll-short-circuit-fetching-events-if-thread-has-been-killed.patch
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