On Thu, 2007-01-18 at 10:46 +1100, Jens Axboe wrote:
> On Wed, Jan 17 2007, Dave Kleikamp wrote:
> > On Thu, 2007-01-18 at 10:18 +1100, Jens Axboe wrote:
> >
> > > Can you try io_schedule() and verify that things just work?
> >
> > I actually did do that in the first place, but wondered if it was the
> > right thing to introduce the accounting changes that came with that.
> > I'll change it back to io_schedule() and test it again, just to make
> > sure.
>
> It appears to be the correct change to me - you really are waiting for
> IO resources (otherwise it would not hang with the plug change), so
> doing an inc/dec of iowait around the schedule should be done.
Okay, here it is.
> > If that's the right fix, I can push it directly since it won't have any
> > dependencies on your patches.
>
> Perfect!
It should make the next -mm.
JFS: call io_schedule() instead of schedule() to avoid deadlock
The introduction of Jens Axboe's explicit i/o plugging patches introduced a
deadlock in jfs. This was caused by the process initiating I/O not
unplugging the queue before waiting on the commit thread. The commit
thread itself was waiting for that I/O to complete. Calling io_schedule()
rather than schedule() unplugs the I/O queue avoiding the deadlock, and it
appears to be the right function to call in any case.
Signed-off-by: Dave Kleikamp <shaggy@xxxxxxxxxxxxxx>
---
commit 4aa0d230c2cfc1ac4bcf7c5466f9943cf14233a9
tree b873dce6146f4880c6c48ab53c0079566f52a60b
parent 82d5b9a7c63054a9a2cd838ffd177697f86e7e34
author Dave Kleikamp <shaggy@xxxxxxxxxxxxxxxxxx> Wed, 17 Jan 2007 21:18:35 -0600
committer Dave Kleikamp <shaggy@xxxxxxxxxxxxxxxxxx> Wed, 17 Jan 2007 21:18:35 -0600
fs/jfs/jfs_lock.h | 2 +-
fs/jfs/jfs_metapage.c | 2 +-
fs/jfs/jfs_txnmgr.c | 2 +-
3 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/fs/jfs/jfs_lock.h b/fs/jfs/jfs_lock.h
index 7d78e83..df48ece 100644
--- a/fs/jfs/jfs_lock.h
+++ b/fs/jfs/jfs_lock.h
@@ -42,7 +42,7 @@ do { \
if (cond) \
break; \
unlock_cmd; \
- schedule(); \
+ io_schedule(); \
lock_cmd; \
} \
current->state = TASK_RUNNING; \
diff --git a/fs/jfs/jfs_metapage.c b/fs/jfs/jfs_metapage.c
index ceaf03b..58deae0 100644
--- a/fs/jfs/jfs_metapage.c
+++ b/fs/jfs/jfs_metapage.c
@@ -56,7 +56,7 @@ static inline void __lock_metapage(struct metapage *mp)
set_current_state(TASK_UNINTERRUPTIBLE);
if (metapage_locked(mp)) {
unlock_page(mp->page);
- schedule();
+ io_schedule();
lock_page(mp->page);
}
} while (trylock_metapage(mp));
diff --git a/fs/jfs/jfs_txnmgr.c b/fs/jfs/jfs_txnmgr.c
index d558e51..6988a10 100644
--- a/fs/jfs/jfs_txnmgr.c
+++ b/fs/jfs/jfs_txnmgr.c
@@ -135,7 +135,7 @@ static inline void TXN_SLEEP_DROP_LOCK(wait_queue_head_t * event)
add_wait_queue(event, &wait);
set_current_state(TASK_UNINTERRUPTIBLE);
TXN_UNLOCK();
- schedule();
+ io_schedule();
current->state = TASK_RUNNING;
remove_wait_queue(event, &wait);
}
--
David Kleikamp
IBM Linux Technology Center
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