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authorSebastian Andrzej Siewior <bigeasy@linutronix.de>2014-02-17 17:30:03 +0100
committerSebastian Andrzej Siewior <bigeasy@linutronix.de>2016-02-13 00:36:13 +0100
commit71adb2d5c543487116e1ba0caf77c2e99cac5f16 (patch)
treeeed85b1af6657f2681f0aa8addd63da3abf33df8
parentfa5fee884e19f4a6e4995aab124f81aba1d48a87 (diff)
downloadrt-linux-71adb2d5c543487116e1ba0caf77c2e99cac5f16.tar.gz
fs: jbd2: pull your plug when waiting for space
Two cps in parallel managed to stall the the ext4 fs. It seems that journal code is either waiting for locks or sleeping waiting for something to happen. This seems similar to what Mike observed on ext3, here is his description: |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: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
-rw-r--r--fs/jbd2/checkpoint.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/jbd2/checkpoint.c b/fs/jbd2/checkpoint.c
index 684996c8a3a4a..6e18a06aaabef 100644
--- a/fs/jbd2/checkpoint.c
+++ b/fs/jbd2/checkpoint.c
@@ -116,6 +116,8 @@ void __jbd2_log_wait_for_space(journal_t *journal)
nblocks = jbd2_space_needed(journal);
while (jbd2_log_space_left(journal) < nblocks) {
write_unlock(&journal->j_state_lock);
+ if (current->plug)
+ io_schedule();
mutex_lock(&journal->j_checkpoint_mutex);
/*