linux-dev - Linux kernel development work

Age	Commit message (Collapse)	Author	Files	Lines
2017-01-27	block: add a op_is_flush helper	Christoph Hellwig	1	-3/+2
	This centralizes the checks for bios that needs to be go into the flush state machine. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-01-27	blk-mq-sched: change ->dispatch_requests() to ->dispatch_request()	Jens Axboe	1	-8/+15
	When we invoke dispatch_requests(), the scheduler empties everything into the passed in list. This isn't always a good thing, since it means that we remove items that we could have potentially merged with. Change the function to dispatch single requests at the time. If we do that, we can backoff exactly at the point where the device can't consume more IO, and leave the rest with the scheduler for better merging and future dispatch decision making. Signed-off-by: Jens Axboe <axboe@fb.com> Reviewed-by: Omar Sandoval <osandov@fb.com> Tested-by: Hannes Reinecke <hare@suse.com>
2017-01-27	blk-mq-sched: fix starvation for multiple hardware queues and shared tags	Jens Axboe	1	-0/+28
	If we have both multiple hardware queues and shared tag map between devices, we need to ensure that we propagate the hardware queue restart bit higher up. This is because we can get into a situation where we don't have any IO pending on a hardware queue, yet we fail getting a tag to start new IO. If that happens, it's not enough to mark the hardware queue as needing a restart, we need to bubble that up to the higher level queue as well. Signed-off-by: Jens Axboe <axboe@fb.com> Reviewed-by: Omar Sandoval <osandov@fb.com> Tested-by: Hannes Reinecke <hare@suse.com>
2017-01-26	blk-mq-sched: check for successful allocation before assigning tag	Jens Axboe	1	-1/+2
	We don't trigger this from the normal IO path, since we always use blocking allocations from there. But Bart saw it testing multipath dm, since that is a heavy user of atomic request allocations in the map and clone path. Reported-by: Bart Van Assche <bart.vanassche@sandisk.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-01-26	blk-mq: don't lose flags passed in to blk_mq_alloc_request()	Jens Axboe	1	-1/+1
	If we come in from blk_mq_alloc_requst() with NOWAIT set in flags, we must ensure that we don't later overwrite that in blk_mq_sched_get_request(). Initialize alloc_data->flags before passing it in. Reported-by: Bart Van Assche <bart.vanassche@sandisk.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-01-17	blk-mq-sched: allow setting of default IO scheduler	Jens Axboe	1	-0/+20
	Add Kconfig entries to manage what devices get assigned an MQ scheduler, and add a blk-mq flag for drivers to opt out of scheduling. The latter is useful for admin type queues that still allocate a blk-mq queue and tag set, but aren't use for normal IO. Signed-off-by: Jens Axboe <axboe@fb.com> Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: Omar Sandoval <osandov@fb.com>
2017-01-17	blk-mq-sched: add framework for MQ capable IO schedulers	Jens Axboe	1	-0/+368
	This adds a set of hooks that intercepts the blk-mq path of allocating/inserting/issuing/completing requests, allowing us to develop a scheduler within that framework. We reuse the existing elevator scheduler API on the registration side, but augment that with the scheduler flagging support for the blk-mq interfce, and with a separate set of ops hooks for MQ devices. We split driver and scheduler tags, so we can run the scheduling independently of device queue depth. Signed-off-by: Jens Axboe <axboe@fb.com> Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: Omar Sandoval <osandov@fb.com>