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authorJan Kara <jack@suse.cz>2018-12-28 00:39:16 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2018-12-28 12:11:51 -0800
commit88dbcbb3a4847f5e6dfeae952d3105497700c128 (patch)
treefece39ef970f6f022e4f010aacbc0b68691a2fae
parent89cb0888ca1483ad72648844ddd1b801863a8949 (diff)
downloadlinux-88dbcbb3a4847f5e6dfeae952d3105497700c128.tar.bz2
blkdev: avoid migration stalls for blkdev pages
Currently, block device pages don't provide a ->migratepage callback and thus fallback_migrate_page() is used for them. This handler cannot deal with dirty pages in async mode and also with the case a buffer head is in the LRU buffer head cache (as it has elevated b_count). Thus such page can block memory offlining. Fix the problem by using buffer_migrate_page_norefs() for migrating block device pages. That function takes care of dropping bh LRU in case migration would fail due to elevated buffer refcount to avoid stalls and can also migrate dirty pages without writing them. Link: http://lkml.kernel.org/r/20181211172143.7358-6-jack@suse.cz Signed-off-by: Jan Kara <jack@suse.cz> Acked-by: Mel Gorman <mgorman@suse.de> Cc: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/block_dev.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/fs/block_dev.c b/fs/block_dev.c
index a80b4f0ee7c4..de2135178e62 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1966,6 +1966,7 @@ static const struct address_space_operations def_blk_aops = {
.writepages = blkdev_writepages,
.releasepage = blkdev_releasepage,
.direct_IO = blkdev_direct_IO,
+ .migratepage = buffer_migrate_page_norefs,
.is_dirty_writeback = buffer_check_dirty_writeback,
};