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authorMel Gorman <mgorman@suse.de>2012-01-12 17:19:34 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2012-01-12 20:13:09 -0800
commitb969c4ab9f182a6e1b2a0848be349f99714947b0 (patch)
treedc1c6e4375cfec7b15f13a37307eba8a9e07f40f /include/linux/fs.h
parent7335084d446b83cbcb15da80497d03f0c1dc9e21 (diff)
downloadop-kernel-dev-b969c4ab9f182a6e1b2a0848be349f99714947b0.zip
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mm: compaction: determine if dirty pages can be migrated without blocking within ->migratepage
Asynchronous compaction is used when allocating transparent hugepages to avoid blocking for long periods of time. Due to reports of stalling, there was a debate on disabling synchronous compaction but this severely impacted allocation success rates. Part of the reason was that many dirty pages are skipped in asynchronous compaction by the following check; if (PageDirty(page) && !sync && mapping->a_ops->migratepage != migrate_page) rc = -EBUSY; This skips over all mapping aops using buffer_migrate_page() even though it is possible to migrate some of these pages without blocking. This patch updates the ->migratepage callback with a "sync" parameter. It is the responsibility of the callback to fail gracefully if migration would block. Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Dave Jones <davej@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Andy Isaacson <adi@hexapodia.org> Cc: Nai Xia <nai.xia@gmail.com> Cc: Johannes Weiner <jweiner@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/fs.h')
-rw-r--r--include/linux/fs.h9
1 files changed, 6 insertions, 3 deletions
diff --git a/include/linux/fs.h b/include/linux/fs.h
index a7409bc..b92b73d 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -609,9 +609,12 @@ struct address_space_operations {
loff_t offset, unsigned long nr_segs);
int (*get_xip_mem)(struct address_space *, pgoff_t, int,
void **, unsigned long *);
- /* migrate the contents of a page to the specified target */
+ /*
+ * migrate the contents of a page to the specified target. If sync
+ * is false, it must not block.
+ */
int (*migratepage) (struct address_space *,
- struct page *, struct page *);
+ struct page *, struct page *, bool);
int (*launder_page) (struct page *);
int (*is_partially_uptodate) (struct page *, read_descriptor_t *,
unsigned long);
@@ -2537,7 +2540,7 @@ extern int generic_check_addressable(unsigned, u64);
#ifdef CONFIG_MIGRATION
extern int buffer_migrate_page(struct address_space *,
- struct page *, struct page *);
+ struct page *, struct page *, bool);
#else
#define buffer_migrate_page NULL
#endif
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