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authorMiao Xie <miaox@cn.fujitsu.com>2014-01-14 20:31:52 +0800
committerChris Mason <clm@fb.com>2014-01-28 13:20:37 -0800
commit23c671a58831a5aaca3b56b915c8394a274a96df (patch)
treeb8ae22e5b2e0566754f5343c1f15fd048c9eb3de
parent2c21b4d733d6e50514e30ffd87110364ddda695b (diff)
Btrfs: flush the dirty pages of the ordered extent aggressively during logging csum
The performance of fsync dropped down suddenly sometimes, the main reason of this problem was that we might only flush part dirty pages in a ordered extent, then got that ordered extent, wait for the csum calcucation. But if no task flushed the left part, we would wait until the flusher flushed them, sometimes we need wait for several seconds, it made the performance drop down suddenly. (On my box, it drop down from 56MB/s to 4-10MB/s) This patch improves the above problem by flushing left dirty pages aggressively. Test Environment: CPU: 2CPU * 2Cores Memory: 4GB Partition: 20GB(HDD) Test Command: # sysbench --num-threads=8 --test=fileio --file-num=1 \ > --file-total-size=8G --file-block-size=32768 \ > --file-io-mode=sync --file-fsync-freq=100 \ > --file-fsync-end=no --max-requests=10000 \ > --file-test-mode=rndwr run Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
-rw-r--r--fs/btrfs/tree-log.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index b561e7a4007..b142b6dc96c 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -3637,7 +3637,11 @@ again:
* start over after this.
*/
- wait_event(ordered->wait, ordered->csum_bytes_left == 0);
+ if (ordered->csum_bytes_left) {
+ btrfs_start_ordered_extent(inode, ordered, 0);
+ wait_event(ordered->wait,
+ ordered->csum_bytes_left == 0);
+ }
list_for_each_entry(sum, &ordered->list, list) {
ret = btrfs_csum_file_blocks(trans, log, sum);