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@@ -1,103 +0,0 @@
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-From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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-From: "Kirill A. Shutemov" <[email protected]>
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-Date: Fri, 23 Mar 2018 09:19:21 +0100
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-Subject: [PATCH] mm/shmem: do not wait for lock_page() in
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- shmem_unused_huge_shrink()
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-MIME-Version: 1.0
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-Content-Type: text/plain; charset=UTF-8
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-Content-Transfer-Encoding: 8bit
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-
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-shmem_unused_huge_shrink() gets called from reclaim path. Waiting for
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-page lock may lead to deadlock there.
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-
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-There was a bug report that may be attributed to this:
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-
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-http://lkml.kernel.org/r/[email protected]
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-
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-Replace lock_page() with trylock_page() and skip the page if we failed to
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-lock it. We will get to the page on the next scan.
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-
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-We can test for the PageTransHuge() outside the page lock as we only need
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-protection against splitting the page under us. Holding pin oni the page
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-is enough for this.
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-
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-Link: http://lkml.kernel.org/r/[email protected]
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-Fixes: 779750d20b93 ("shmem: split huge pages beyond i_size under memory pressure")
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-Signed-off-by: Kirill A. Shutemov <[email protected]>
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-Reported-by: Eric Wheeler <[email protected]>
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-Acked-by: Michal Hocko <[email protected]>
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-Reviewed-by: Andrew Morton <[email protected]>
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-Cc: Tetsuo Handa <[email protected]>
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-Cc: Hugh Dickins <[email protected]>
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-Cc: <[email protected]> [4.8+]
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-Signed-off-by: Andrew Morton <>
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-(cherry-picked from https://git.kernel.org/pub/scm/linux/kernel/git/mhocko/mm.git/commit/?h=since-4.15&id=73eccc61c701ee7b4223aea2079542a712feeea7)
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-Signed-off-by: Fabian Grünbichler <[email protected]>
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----
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- mm/shmem.c | 31 ++++++++++++++++++++-----------
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- 1 file changed, 20 insertions(+), 11 deletions(-)
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-
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-diff --git a/mm/shmem.c b/mm/shmem.c
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-index f6695c111086..800482fe6ed6 100644
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---- a/mm/shmem.c
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-+++ b/mm/shmem.c
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-@@ -497,36 +497,45 @@ static unsigned long shmem_unused_huge_shrink(struct shmem_sb_info *sbinfo,
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- info = list_entry(pos, struct shmem_inode_info, shrinklist);
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- inode = &info->vfs_inode;
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-
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-- if (nr_to_split && split >= nr_to_split) {
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-- iput(inode);
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-- continue;
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-- }
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-+ if (nr_to_split && split >= nr_to_split)
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-+ goto leave;
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-
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-- page = find_lock_page(inode->i_mapping,
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-+ page = find_get_page(inode->i_mapping,
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- (inode->i_size & HPAGE_PMD_MASK) >> PAGE_SHIFT);
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- if (!page)
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- goto drop;
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-
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-+ /* No huge page at the end of the file: nothing to split */
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- if (!PageTransHuge(page)) {
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-- unlock_page(page);
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- put_page(page);
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- goto drop;
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- }
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-
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-+ /*
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-+ * Leave the inode on the list if we failed to lock
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-+ * the page at this time.
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-+ *
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-+ * Waiting for the lock may lead to deadlock in the
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-+ * reclaim path.
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-+ */
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-+ if (!trylock_page(page)) {
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-+ put_page(page);
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-+ goto leave;
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-+ }
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-+
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- ret = split_huge_page(page);
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- unlock_page(page);
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- put_page(page);
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-
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-- if (ret) {
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-- /* split failed: leave it on the list */
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-- iput(inode);
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-- continue;
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-- }
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-+ /* If split failed leave the inode on the list */
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-+ if (ret)
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-+ goto leave;
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-
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- split++;
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- drop:
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- list_del_init(&info->shrinklist);
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- removed++;
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-+leave:
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- iput(inode);
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- }
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-
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---
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-2.14.2
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-
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Fabian Grünbichler