[PATCH RT 6/8] fs, jbd: pull your plug when waiting for space

[Steven Rostedt]

From: Mike Galbraith <mgalbraith@xxxxxxx>

With an -rt kernel, and a heavy sync IO load, tasks can jam
up on journal locks without unplugging, which can lead to
terminal IO starvation.  Unplug and schedule when waiting for space.

Signed-off-by: Mike Galbraith <mgalbraith@xxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Theodore Tso <tytso@xxxxxxx>
Link: http://lkml.kernel.org/r/1341812414.7370.73.camel@xxxxxxxxxxxxxxxxx
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
---
 fs/jbd/checkpoint.c |    2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/jbd/checkpoint.c b/fs/jbd/checkpoint.c
index 5c93ffc..ddbd223 100644
--- a/fs/jbd/checkpoint.c
+++ b/fs/jbd/checkpoint.c
@@ -129,6 +129,8 @@ void __log_wait_for_space(journal_t *journal)
 		if (journal->j_flags & JFS_ABORT)
 			return;
 		spin_unlock(&journal->j_state_lock);
+		if (current->plug)
+			io_schedule();
 		mutex_lock(&journal->j_checkpoint_mutex);
 
 		/*
-- 
1.7.10.4


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