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authorDavid Rientjes <rientjes@google.com>2017-05-12 15:47:03 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-05-12 15:57:16 -0700
commit338a16ba154959b049458d4f507d60f694550b68 (patch)
tree1c70e3bc5d6a1692874e9f569d944aeac684522a
parent876f29460cbd4086b43475890c1bf2488fa11d40 (diff)
downloadlinux-stericsson-338a16ba154959b049458d4f507d60f694550b68.tar.gz
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@chino.kir.corp.google.com Signed-off-by: David Rientjes <rientjes@google.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/khugepaged.c7
1 files changed, 3 insertions, 4 deletions
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index d1943e54ba95..945fd1ca49b5 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -612,7 +612,8 @@ static void __collapse_huge_page_copy(pte_t *pte, struct page *page,
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(pte_t *pte, struct page *page,
spin_unlock(ptl);
free_page_and_swap_cache(src_page);
}
-
- address += PAGE_SIZE;
- page++;
+ cond_resched();
}
}