Re: 2.6.8-rc2-mm1

Andrew Morton
2004-07-31T18:48:50Z

Zwane Mwaikambo <zwane@linuxpower.ca> wrote:
>
> Ingo i believe you have a patch for this, could you push it to Andrew?

I suspect Ingo's patch will be livelockable under some circumstances.

I suspect mine is too, only less so.

> I reckon it's provoked by CONFIG_PREEMPT.

This should fix.

diff -puN fs/jbd/checkpoint.c~journal_clean_checkpoint_list-latency-fix-fix fs/jbd/checkpoint.c
--- 25/fs/jbd/checkpoint.c~journal_clean_checkpoint_list-latency-fix-fix 2004-07-31 11:43:39.320530424 -0700
+++ 25-akpm/fs/jbd/checkpoint.c 2004-07-31 11:44:11.859583736 -0700
@@ -497,8 +497,7 @@ int __journal_clean_checkpoint_list(jour
* We don't test cond_resched() here because another CPU could
* be waiting on j_list_lock() while holding a different lock.
*/
- if ((ret & 127) == 127) {
- spin_unlock(&journal->j_list_lock);
+ if (transaction && (ret & 127) == 127) {
/*
* We need to schedule away. Rotate both this
* transaction's buffer list and the checkpoint list to
@@ -512,6 +511,7 @@ int __journal_clean_checkpoint_list(jour
if (transaction)
journal->j_checkpoint_transactions =
transaction->t_cpnext;
+ spin_unlock(&journal->j_list_lock);
return ret;
}
#endif
_