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authorChristoph Hellwig <hch@lst.de>2010-06-17 08:54:16 +0200
committerJens Axboe <jaxboe@fusionio.com>2010-08-07 18:15:44 +0200
commit41f2df62894bfcd3bf868af916b32b90aa7168dc (patch)
treeb582399975cd1cf19aa8b6e67623f252b7cada85
parent01b6b67edabe864391163dc6405e2cb454f108db (diff)
block: BARRIER request should imply SYNC
A barrier request should by defintion have priority in get_request and let the queue be unplugged immediately as it's blocking all forward progress due to the queue draining. Most filesystems already get this implicitly by the way how submit_bh treats the buffer_ordered flag, and gfs2 sets it explicitly. But btrfs and XFS are still forgetting to set the flag, as is blkdev_issue_flush and some places in DM/MD. For XFS on metadata heavy workloads this gives a consistent speedup in the 2-3% range. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
-rw-r--r--fs/gfs2/log.c2
-rw-r--r--include/linux/fs.h4
2 files changed, 3 insertions, 3 deletions
diff --git a/fs/gfs2/log.c b/fs/gfs2/log.c
index 6a857e24f947..efc3539ac5a1 100644
--- a/fs/gfs2/log.c
+++ b/fs/gfs2/log.c
@@ -595,7 +595,7 @@ static void log_write_header(struct gfs2_sbd *sdp, u32 flags, int pull)
if (test_bit(SDF_NOBARRIERS, &sdp->sd_flags))
goto skip_barrier;
get_bh(bh);
- submit_bh(WRITE_SYNC | (1 << BIO_RW_BARRIER) | (1 << BIO_RW_META), bh);
+ submit_bh(WRITE_BARRIER | (1 << BIO_RW_META), bh);
wait_on_buffer(bh);
if (buffer_eopnotsupp(bh)) {
clear_buffer_eopnotsupp(bh);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 68ca1b0491af..598878831497 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -136,7 +136,7 @@ struct inodes_stat_t {
* SWRITE_SYNC
* SWRITE_SYNC_PLUG Like WRITE_SYNC/WRITE_SYNC_PLUG, but locks the buffer.
* See SWRITE.
- * WRITE_BARRIER Like WRITE, but tells the block layer that all
+ * WRITE_BARRIER Like WRITE_SYNC, but tells the block layer that all
* previously submitted writes must be safely on storage
* before this one is started. Also guarantees that when
* this write is complete, it itself is also safely on
@@ -159,7 +159,7 @@ struct inodes_stat_t {
#define SWRITE_SYNC_PLUG \
(SWRITE | (1 << BIO_RW_SYNCIO) | (1 << BIO_RW_NOIDLE))
#define SWRITE_SYNC (SWRITE_SYNC_PLUG | (1 << BIO_RW_UNPLUG))
-#define WRITE_BARRIER (WRITE | (1 << BIO_RW_BARRIER))
+#define WRITE_BARRIER (WRITE_SYNC | (1 << BIO_RW_BARRIER))
/*
* These aren't really reads or writes, they pass down information about