From: Mike Galbraith Date: Wed, 11 Jul 2012 22:05:20 +0000 Subject: fs, jbd: pull your plug when waiting for space Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.0/patches-4.0.5-rt3.tar.xz 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 Cc: Steven Rostedt Cc: Theodore Tso Link: http://lkml.kernel.org/r/1341812414.7370.73.camel@marge.simpson.net Signed-off-by: Thomas Gleixner --- fs/jbd/checkpoint.c | 2 ++ 1 file changed, 2 insertions(+) --- a/fs/jbd/checkpoint.c +++ b/fs/jbd/checkpoint.c @@ -129,6 +129,8 @@ void __log_wait_for_space(journal_t *jou if (journal->j_flags & JFS_ABORT) return; spin_unlock(&journal->j_state_lock); + if (current->plug) + io_schedule(); mutex_lock(&journal->j_checkpoint_mutex); /*