From a212d1a71deea10ba4f6de2aaac0221be34ddb29 Mon Sep 17 00:00:00 2001 From: Tao Ma Date: Tue, 7 Jun 2011 11:56:50 +0800 Subject: [PATCH] jbd: Use WRITE_SYNC in journal checkpoint. In journal checkpoint, we write the buffer and wait for its finish. But in cfq, the async queue has a very low priority, and in our test, if there are too many sync queues and every queue is filled up with requests, and the process will hang waiting for the log space. So this patch tries to use WRITE_SYNC in __flush_batch so that the request will be moved into sync queue and handled by cfq timely. We also use the new plug, sot that all the WRITE_SYNC requests can be given as a whole when we unplug it. Reported-by: Robin Dong Signed-off-by: Tao Ma Signed-off-by: Jan Kara --- fs/jbd/checkpoint.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/fs/jbd/checkpoint.c b/fs/jbd/checkpoint.c index 61655a3..f94fc48 100644 --- a/fs/jbd/checkpoint.c +++ b/fs/jbd/checkpoint.c @@ -22,6 +22,7 @@ #include #include #include +#include #include /* @@ -257,9 +258,12 @@ static void __flush_batch(journal_t *journal, struct buffer_head **bhs, int *batch_count) { int i; + struct blk_plug plug; + blk_start_plug(&plug); for (i = 0; i < *batch_count; i++) - write_dirty_buffer(bhs[i], WRITE); + write_dirty_buffer(bhs[i], WRITE_SYNC); + blk_finish_plug(&plug); for (i = 0; i < *batch_count; i++) { struct buffer_head *bh = bhs[i]; -- 2.7.4