pm24.git/include/linux/elevator.h, branch v4.12-rc2

blk-mq-debugfs: allow schedulers to register debugfs attributes

2017-05-04T14:24:40Z

This provides the infrastructure for schedulers to expose their internal state through debugfs. We add a list of queue attributes and a list of hctx attributes to struct elevator_type and wire them up when switching schedulers. Signed-off-by: Omar Sandoval Reviewed-by: Hannes Reinecke Add missing seq_file.h header in blk-mq-debugfs.h Signed-off-by: Jens Axboe

block: Remove elevator_change()

2017-05-02T13:52:08Z

Since commit 84253394927c ("remove the mg_disk driver") removed the only caller of elevator_change(), also remove the elevator_change() function itself. Signed-off-by: Bart Van Assche Cc: Christoph Hellwig Cc: Markus Trippelsdorf Signed-off-by: Jens Axboe

blk-mq-sched: make completed_request() callback more useful

2017-04-14T20:06:57Z

Currently, this callback is called right after put_request() and has no distinguishable purpose. Instead, let's call it before put_request() as soon as I/O has completed on the request, before we account it in blk-stat. With this, Kyber can enable stats when it sees a latency outlier and make sure the outlier gets accounted. Signed-off-by: Omar Sandoval Signed-off-by: Jens Axboe

blk-mq-sched: provide hooks for initializing hardware queue data

2017-04-07T18:45:41Z

Schedulers need to be informed when a hardware queue is added or removed at runtime so they can allocate/free per-hardware queue data. So, replace the blk_mq_sched_init_hctx_data() helper, which only makes sense at init time, with .init_hctx() and .exit_hctx() hooks. Signed-off-by: Omar Sandoval Signed-off-by: Jens Axboe

blk-mq-sched: fix crash in switch error path

2017-04-07T14:56:48Z

In elevator_switch(), if blk_mq_init_sched() fails, we attempt to fall back to the original scheduler. However, at this point, we've already torn down the original scheduler's tags, so this causes a crash. Doing the fallback like the legacy elevator path is much harder for mq, so fix it by just falling back to none, instead. Signed-off-by: Omar Sandoval Signed-off-by: Jens Axboe

blk-mq: pass bio to blk_mq_sched_get_rq_priv

2017-02-10T16:09:59Z

bio is used in bfq-mq's get_rq_priv, to get the request group. We could pass directly the group here, but I thought that passing the bio was more general, giving the possibility to get other pieces of information if needed. Signed-off-by: Paolo Valente Signed-off-by: Jens Axboe

block: optionally merge discontiguous discard bios into a single request

2017-02-08T20:43:08Z

Add a new merge strategy that merges discard bios into a request until the maximum number of discard ranges (or the maximum discard size) is reached from the plug merging code. I/O scheduler merging is not wired up yet but might also be useful, although not for fast devices like NVMe which are the only user for now. Note that for now we don't support limiting the size of each discard range, but if needed that can be added later. Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe

block: enumify ELEVATOR_*_MERGE

2017-02-08T20:43:06Z

Switch these constants to an enum, and make let the compiler ensure that all callers of blk_try_merge and elv_merge handle all potential values. Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe

blk-mq-sched: change ->dispatch_requests() to ->dispatch_request()

2017-01-27T15:20:35Z

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 Reviewed-by: Omar Sandoval Tested-by: Hannes Reinecke

blk-mq-sched: add framework for MQ capable IO schedulers

2017-01-17T17:04:20Z

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 Reviewed-by: Bart Van Assche Reviewed-by: Omar Sandoval