| Message ID | 20191006024516.19996-3-ming.lei@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | blk-mq: improvement on handling IO during CPU hotplug | expand |
On 10/6/19 4:45 AM, Ming Lei wrote: > We will stop hw queue and wait for completion of in-flight requests > when one hctx is becoming dead in the following patch. This way may > cause dead-lock for some stacking blk-mq drivers, such as dm-rq and > loop. > > Add blk-mq flag of BLK_MQ_F_NO_MANAGED_IRQ and mark it for dm-rq and > loop, so we needn't to wait for completion of in-flight requests of > dm-rq & loop, then the potential dead-lock can be avoided. > > Cc: Bart Van Assche <bvanassche@acm.org> > Cc: Hannes Reinecke <hare@suse.com> > Cc: Christoph Hellwig <hch@lst.de> > Cc: Thomas Gleixner <tglx@linutronix.de> > Cc: Keith Busch <keith.busch@intel.com> > Signed-off-by: Ming Lei <ming.lei@redhat.com> > --- > block/blk-mq-debugfs.c | 1 + > drivers/block/loop.c | 2 +- > drivers/md/dm-rq.c | 2 +- > include/linux/blk-mq.h | 1 + > 4 files changed, 4 insertions(+), 2 deletions(-) > I would have preferred to queue this patch after the next one; introducing a flag which doesn't do anything is a bit odd to me. But anyway: Reviewed-by: Hannes Reinecke <hare@suse.com> Cheers, Hannes
diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c index af40a02c46ee..24fff8c90942 100644 --- a/block/blk-mq-debugfs.c +++ b/block/blk-mq-debugfs.c @@ -240,6 +240,7 @@ static const char *const hctx_flag_name[] = { HCTX_FLAG_NAME(TAG_SHARED), HCTX_FLAG_NAME(BLOCKING), HCTX_FLAG_NAME(NO_SCHED), + HCTX_FLAG_NAME(NO_MANAGED_IRQ), }; #undef HCTX_FLAG_NAME diff --git a/drivers/block/loop.c b/drivers/block/loop.c index f6f77eaa7217..751a28a1d4b0 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -1999,7 +1999,7 @@ static int loop_add(struct loop_device **l, int i) lo->tag_set.queue_depth = 128; lo->tag_set.numa_node = NUMA_NO_NODE; lo->tag_set.cmd_size = sizeof(struct loop_cmd); - lo->tag_set.flags = BLK_MQ_F_SHOULD_MERGE; + lo->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_NO_MANAGED_IRQ; lo->tag_set.driver_data = lo; err = blk_mq_alloc_tag_set(&lo->tag_set); diff --git a/drivers/md/dm-rq.c b/drivers/md/dm-rq.c index 3f8577e2c13b..5f1ff70ac029 100644 --- a/drivers/md/dm-rq.c +++ b/drivers/md/dm-rq.c @@ -547,7 +547,7 @@ int dm_mq_init_request_queue(struct mapped_device *md, struct dm_table *t) md->tag_set->ops = &dm_mq_ops; md->tag_set->queue_depth = dm_get_blk_mq_queue_depth(); md->tag_set->numa_node = md->numa_node_id; - md->tag_set->flags = BLK_MQ_F_SHOULD_MERGE; + md->tag_set->flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_NO_MANAGED_IRQ; md->tag_set->nr_hw_queues = dm_get_blk_mq_nr_hw_queues(); md->tag_set->driver_data = md; diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h index 079c282e4471..ee60885ec855 100644 --- a/include/linux/blk-mq.h +++ b/include/linux/blk-mq.h @@ -226,6 +226,7 @@ struct blk_mq_ops { enum { BLK_MQ_F_SHOULD_MERGE = 1 << 0, BLK_MQ_F_TAG_SHARED = 1 << 1, + BLK_MQ_F_NO_MANAGED_IRQ = 1 << 2, BLK_MQ_F_BLOCKING = 1 << 5, BLK_MQ_F_NO_SCHED = 1 << 6, BLK_MQ_F_ALLOC_POLICY_START_BIT = 8,
We will stop hw queue and wait for completion of in-flight requests when one hctx is becoming dead in the following patch. This way may cause dead-lock for some stacking blk-mq drivers, such as dm-rq and loop. Add blk-mq flag of BLK_MQ_F_NO_MANAGED_IRQ and mark it for dm-rq and loop, so we needn't to wait for completion of in-flight requests of dm-rq & loop, then the potential dead-lock can be avoided. Cc: Bart Van Assche <bvanassche@acm.org> Cc: Hannes Reinecke <hare@suse.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Keith Busch <keith.busch@intel.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> --- block/blk-mq-debugfs.c | 1 + drivers/block/loop.c | 2 +- drivers/md/dm-rq.c | 2 +- include/linux/blk-mq.h | 1 + 4 files changed, 4 insertions(+), 2 deletions(-)