On Mon, Jul 24 2017 at 5:16am -0400, Damien Le Moal <damien.lemoal@xxxxxxx> wrote: > > > On 7/24/17 17:03, Christoph Hellwig wrote: > > On Mon, Jul 24, 2017 at 04:44:22PM +0900, Damien Le Moal wrote: > >> Avoid metadata flush to be blocked by the writeback throttling code in > >> wbt_wait(). Otherwise, we can end up with a deadlock under heavy write > >> load with all chunk works active. In such situation, a deadlock can > >> happen if the flush work is blocked by the throttling code while holding > >> the metadata lock: as the chunk works will wait for the metadata lock > >> too, no progress can be made. > >> > >> Signed-off-by: Damien Le Moal <damien.lemoal@xxxxxxx> > >> --- > >> drivers/md/dm-zoned-metadata.c | 3 ++- > >> 1 file changed, 2 insertions(+), 1 deletion(-) > >> > >> diff --git a/drivers/md/dm-zoned-metadata.c b/drivers/md/dm-zoned-metadata.c > >> index 884ff7c170a0..f694fb98b002 100644 > >> --- a/drivers/md/dm-zoned-metadata.c > >> +++ b/drivers/md/dm-zoned-metadata.c > >> @@ -567,7 +567,8 @@ static void dmz_write_mblock(struct dmz_metadata *zmd, struct dmz_mblock *mblk, > >> bio->bi_bdev = zmd->dev->bdev; > >> bio->bi_private = mblk; > >> bio->bi_end_io = dmz_mblock_bio_end_io; > >> - bio_set_op_attrs(bio, REQ_OP_WRITE, REQ_META | REQ_PRIO); > >> + bio_set_op_attrs(bio, REQ_OP_WRITE, > >> + REQ_META | REQ_PRIO | REQ_SYNC | REQ_IDLE); > > > > Please just assign bi_opf directly instea dof using bio_set_op_attrs > > in new code. > > OK. Will do. > > > Also what do you need REQ_IDLE for? > > It is not really needed here, but the wbt_should_throttle() code test is: > > if ((bio->bi_opf & (REQ_SYNC | REQ_IDLE)) == (REQ_SYNC | REQ_IDLE)) > return false; > > So if REQ_IDLE is not set, wbt will trigger. > > Having a req flag that says "no wb throttling please" would be a lot > cleaner... Did you have a new version of this patch? Thanks, Mike -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
