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authorNeilBrown <neilb@suse.de>2008-03-05 01:29:30 +0300
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2008-03-05 03:35:17 +0300
commit8311c29d40235062a843f4a8e8a70a44af6fe4c9 (patch)
treec869143fae8f135646300d1bac6639af5bb30dd7 /include/linux/raid
parenta35e63efa1fb18c6f20f38e3ddf3f8ffbcf0f6e7 (diff)
downloadlinux-8311c29d40235062a843f4a8e8a70a44af6fe4c9.tar.xz
md: reduce CPU wastage on idle md array with a write-intent bitmap
On an md array with a write-intent bitmap, a thread wakes up every few seconds and scans the bitmap looking for work to do. If the array is idle, there will be no work to do, but a lot of scanning is done to discover this. So cache the fact that the bitmap is completely clean, and avoid scanning the whole bitmap when the cache is known to be clean. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/raid')
-rw-r--r--include/linux/raid/bitmap.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/raid/bitmap.h b/include/linux/raid/bitmap.h
index e51b531cd0b2..47fbcba11850 100644
--- a/include/linux/raid/bitmap.h
+++ b/include/linux/raid/bitmap.h
@@ -235,6 +235,8 @@ struct bitmap {
unsigned long flags;
+ int allclean;
+
unsigned long max_write_behind; /* write-behind mode */
atomic_t behind_writes;