Re: Processes stuck on D state on Dual Opteron

[Neil Brown]

On Monday April 11, nickpiggin@xxxxxxxxxxxx wrote:
> 
> Neil, have you had a look at the traces? Do they mean much to you?
> 

Just looked. 
bio_alloc_bioset seems implicated, as does sync_page_io.

sync_page_io used to use a 'struct bio' on the stack, but Jens Axboe
change it to use bio_alloc (don't know why..) and I should have 
checked the change better.

sync_page_io can be called on the write out path, so it should use
GFP_NOIO rather than GFP_KERNEL.

See if this helps.... Actually this patch is against 2.6.12-rc2-mm1
which uses md_super_write instead of sync_page_io (which is now only
used for read).  So if you are using a non-mm kernel (which seems to
be the case) you'll need to apply the patch by hand.


Thanks,
NeilBrown

---
Avoid deadlock in sync_page_io by using GFP_NOIO

..as sync_page_io can be called on the write-out path.
Ditto for md_super_write

Signed-off-by: Neil Brown <neilb@xxxxxxxxxxxxxxx>

### Diffstat output
 ./drivers/md/md.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff ./drivers/md/md.c~current~ ./drivers/md/md.c
--- ./drivers/md/md.c~current~	2005-04-08 11:25:26.000000000 +1000
+++ ./drivers/md/md.c	2005-04-12 09:42:29.000000000 +1000
@@ -351,7 +351,7 @@ void md_super_write(mddev_t *mddev, mdk_
 	 * if zero is reached.
 	 * If an error occurred, call md_error
 	 */
-	struct bio *bio = bio_alloc(GFP_KERNEL, 1);
+	struct bio *bio = bio_alloc(GFP_NOIO, 1);
 
 	bio->bi_bdev = rdev->bdev;
 	bio->bi_sector = sector;
@@ -374,7 +374,7 @@ static int bi_complete(struct bio *bio, 
 int sync_page_io(struct block_device *bdev, sector_t sector, int size,
 		   struct page *page, int rw)
 {
-	struct bio *bio = bio_alloc(GFP_KERNEL, 1);
+	struct bio *bio = bio_alloc(GFP_NOIO, 1);
 	struct completion event;
 	int ret;
 
-
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