linux-toradex.git/block/elevator.c, branch v5.15-rc3 Linux kernel for Apalis and Colibri modules block: return ELEVATOR_DISCARD_MERGE if possible 2021-08-09T20:37:47+00:00 Ming Lei ming.lei@redhat.com 2021-07-29T03:42:26+00:00 866663b7b52d2da267b28e12eed89ee781b8fed1 When merging one bio to request, if they are discard IO and the queue supports multi-range discard, we need to return ELEVATOR_DISCARD_MERGE because both block core and related drivers(nvme, virtio-blk) doesn't handle mixed discard io merge(traditional IO merge together with discard merge) well. Fix the issue by returning ELEVATOR_DISCARD_MERGE in this situation, so both blk-mq and drivers just need to handle multi-range discard. Reported-by: Oleksandr Natalenko <oleksandr@natalenko.name> Signed-off-by: Ming Lei <ming.lei@redhat.com> Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name> Fixes: 2705dfb20947 ("block: fix discard request merge") Link: https://lore.kernel.org/r/20210729034226.1591070-1-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk> 
When merging one bio to request, if they are discard IO and the queue
supports multi-range discard, we need to return ELEVATOR_DISCARD_MERGE
because both block core and related drivers(nvme, virtio-blk) doesn't
handle mixed discard io merge(traditional IO merge together with
discard merge) well.

Fix the issue by returning ELEVATOR_DISCARD_MERGE in this situation,
so both blk-mq and drivers just need to handle multi-range discard.

Reported-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Fixes: 2705dfb20947 ("block: fix discard request merge")
Link: https://lore.kernel.org/r/20210729034226.1591070-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
block: remove support for delayed queue registrations 2021-08-09T17:50:43+00:00 Christoph Hellwig hch@lst.de 2021-08-04T09:41:47+00:00 d1254a8749711e0d7441036a74ce592341f89697 Now that device mapper has been changed to register the disk once it is fully ready all this code is unused. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Mike Snitzer <snitzer@redhat.com> Link: https://lore.kernel.org/r/20210804094147.459763-9-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk> 
Now that device mapper has been changed to register the disk once
it is fully ready all this code is unused.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Link: https://lore.kernel.org/r/20210804094147.459763-9-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
blk-mq: Introduce the BLK_MQ_F_NO_SCHED_BY_DEFAULT flag 2021-08-05T17:49:21+00:00 Bart Van Assche bvanassche@acm.org 2021-08-05T17:41:59+00:00 90b7198001f23ea37d3b46dc631bdaa2357a20b1 elevator_get_default() uses the following algorithm to select an I/O scheduler from inside add_disk(): - In case of a single hardware queue or if sharing hardware queues across multiple request queues (BLK_MQ_F_TAG_HCTX_SHARED), use mq-deadline. - Otherwise, use 'none'. This is a good choice for most but not for all block drivers. Make it possible to override the selection of mq-deadline with a new flag, namely BLK_MQ_F_NO_SCHED_BY_DEFAULT. Cc: Christoph Hellwig <hch@lst.de> Cc: Ming Lei <ming.lei@redhat.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Martijn Coenen <maco@android.com> Cc: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Link: https://lore.kernel.org/r/20210805174200.3250718-2-bvanassche@acm.org Signed-off-by: Jens Axboe <axboe@kernel.dk> 
elevator_get_default() uses the following algorithm to select an I/O
scheduler from inside add_disk():
- In case of a single hardware queue or if sharing hardware queues across
  multiple request queues (BLK_MQ_F_TAG_HCTX_SHARED), use mq-deadline.
- Otherwise, use 'none'.

This is a good choice for most but not for all block drivers. Make it
possible to override the selection of mq-deadline with a new flag,
namely BLK_MQ_F_NO_SCHED_BY_DEFAULT.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Martijn Coenen <maco@android.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20210805174200.3250718-2-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
blk: Fix lock inversion between ioc lock and bfqd lock 2021-06-25T00:43:55+00:00 Jan Kara jack@suse.cz 2021-06-23T09:36:34+00:00 fd2ef39cc9a6b9c4c41864ac506906c52f94b06a Lockdep complains about lock inversion between ioc->lock and bfqd->lock: bfqd -> ioc: put_io_context+0x33/0x90 -> ioc->lock grabbed blk_mq_free_request+0x51/0x140 blk_put_request+0xe/0x10 blk_attempt_req_merge+0x1d/0x30 elv_attempt_insert_merge+0x56/0xa0 blk_mq_sched_try_insert_merge+0x4b/0x60 bfq_insert_requests+0x9e/0x18c0 -> bfqd->lock grabbed blk_mq_sched_insert_requests+0xd6/0x2b0 blk_mq_flush_plug_list+0x154/0x280 blk_finish_plug+0x40/0x60 ext4_writepages+0x696/0x1320 do_writepages+0x1c/0x80 __filemap_fdatawrite_range+0xd7/0x120 sync_file_range+0xac/0xf0 ioc->bfqd: bfq_exit_icq+0xa3/0xe0 -> bfqd->lock grabbed put_io_context_active+0x78/0xb0 -> ioc->lock grabbed exit_io_context+0x48/0x50 do_exit+0x7e9/0xdd0 do_group_exit+0x54/0xc0 To avoid this inversion we change blk_mq_sched_try_insert_merge() to not free the merged request but rather leave that upto the caller similarly to blk_mq_sched_try_merge(). And in bfq_insert_requests() we make sure to free all the merged requests after dropping bfqd->lock. Fixes: aee69d78dec0 ("block, bfq: introduce the BFQ-v0 I/O scheduler as an extra scheduler") Reviewed-by: Ming Lei <ming.lei@redhat.com> Acked-by: Paolo Valente <paolo.valente@linaro.org> Signed-off-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20210623093634.27879-3-jack@suse.cz Signed-off-by: Jens Axboe <axboe@kernel.dk> 
Lockdep complains about lock inversion between ioc->lock and bfqd->lock:

bfqd -> ioc:
 put_io_context+0x33/0x90 -> ioc->lock grabbed
 blk_mq_free_request+0x51/0x140
 blk_put_request+0xe/0x10
 blk_attempt_req_merge+0x1d/0x30
 elv_attempt_insert_merge+0x56/0xa0
 blk_mq_sched_try_insert_merge+0x4b/0x60
 bfq_insert_requests+0x9e/0x18c0 -> bfqd->lock grabbed
 blk_mq_sched_insert_requests+0xd6/0x2b0
 blk_mq_flush_plug_list+0x154/0x280
 blk_finish_plug+0x40/0x60
 ext4_writepages+0x696/0x1320
 do_writepages+0x1c/0x80
 __filemap_fdatawrite_range+0xd7/0x120
 sync_file_range+0xac/0xf0

ioc->bfqd:
 bfq_exit_icq+0xa3/0xe0 -> bfqd->lock grabbed
 put_io_context_active+0x78/0xb0 -> ioc->lock grabbed
 exit_io_context+0x48/0x50
 do_exit+0x7e9/0xdd0
 do_group_exit+0x54/0xc0

To avoid this inversion we change blk_mq_sched_try_insert_merge() to not
free the merged request but rather leave that upto the caller similarly
to blk_mq_sched_try_merge(). And in bfq_insert_requests() we make sure
to free all the merged requests after dropping bfqd->lock.

Fixes: aee69d78dec0 ("block, bfq: introduce the BFQ-v0 I/O scheduler as an extra scheduler")
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Acked-by: Paolo Valente <paolo.valente@linaro.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20210623093634.27879-3-jack@suse.cz
Signed-off-by: Jens Axboe <axboe@kernel.dk>
block: Remove unnecessary elevator operation checks 2021-06-18T14:51:48+00:00 Damien Le Moal damien.lemoal@wdc.com 2021-06-18T01:59:22+00:00 e42cfb1da0bf33c313318da201730324c423351d The insert_requests and dispatch_request elevator operations are mandatory for the correct execution of an elevator, and all implemented elevators (bfq, kyber and mq-deadline) implement them. As a result, there is no need to check for these operations before calling them when a queue has an elevator set. This simplifies the code in __blk_mq_sched_dispatch_requests() and blk_mq_sched_insert_request(). To avoid out-of-tree elevators to crash the kernel in case of bad implementation, add a check in elv_register() to verify that these operations are implemented. A small, probably not significant, IOPS improvement of 0.1% is observed with this patch applied (4.117 MIOPS to 4.123 MIOPS, average of 20 fio runs doing 4K random direct reads with psync and 32 jobs). Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Link: https://lore.kernel.org/r/20210618015922.713999-1-damien.lemoal@wdc.com Signed-off-by: Jens Axboe <axboe@kernel.dk> 
The insert_requests and dispatch_request elevator operations are
mandatory for the correct execution of an elevator, and all implemented
elevators (bfq, kyber and mq-deadline) implement them. As a result,
there is no need to check for these operations before calling them when
a queue has an elevator set. This simplifies the code in
__blk_mq_sched_dispatch_requests() and blk_mq_sched_insert_request().

To avoid out-of-tree elevators to crash the kernel in case of bad
implementation, add a check in elv_register() to verify that these
operations are implemented.

A small, probably not significant, IOPS improvement of 0.1% is observed
with this patch applied (4.117 MIOPS to 4.123 MIOPS, average of 20 fio
runs doing 4K random direct reads with psync and 32 jobs).

Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20210618015922.713999-1-damien.lemoal@wdc.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
blk-mq: improve the blk_mq_init_allocated_queue interface 2021-06-11T17:53:02+00:00 Christoph Hellwig hch@lst.de 2021-06-02T06:53:17+00:00 26a9750aa875126e4b7fc5ee6de652a529c5b7ee Don't return the passed in request_queue but a normal error code, and drop the elevator_init argument in favor of just calling elevator_init_mq directly from dm-rq. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Link: https://lore.kernel.org/r/20210602065345.355274-3-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk> 
Don't return the passed in request_queue but a normal error code, and
drop the elevator_init argument in favor of just calling elevator_init_mq
directly from dm-rq.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210602065345.355274-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
blk-mq: set default elevator as deadline in case of hctx shared tagset 2021-04-07T16:15:23+00:00 Ming Lei ming.lei@redhat.com 2021-04-06T03:19:33+00:00 580dca8143d215977811bd2ff881e1e4f6ff39f0 Yanhui found that write performance is degraded a lot after applying hctx shared tagset on one test machine with megaraid_sas. And turns out it is caused by none scheduler which becomes default elevator caused by hctx shared tagset patchset. Given more scsi HBAs will apply hctx shared tagset, and the similar performance exists for them too. So keep previous behavior by still using default mq-deadline for queues which apply hctx shared tagset, just like before. Fixes: 32bc15afed04 ("blk-mq: Facilitate a shared sbitmap per tagset") Reported-by: Yanhui Ma <yama@redhat.com> Cc: John Garry <john.garry@huawei.com> Cc: Hannes Reinecke <hare@suse.de> Signed-off-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: John Garry <john.garry@huawei.com> Link: https://lore.kernel.org/r/20210406031933.767228-1-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk> 
Yanhui found that write performance is degraded a lot after applying
hctx shared tagset on one test machine with megaraid_sas. And turns out
it is caused by none scheduler which becomes default elevator caused by
hctx shared tagset patchset.

Given more scsi HBAs will apply hctx shared tagset, and the similar
performance exists for them too.

So keep previous behavior by still using default mq-deadline for queues
which apply hctx shared tagset, just like before.

Fixes: 32bc15afed04 ("blk-mq: Facilitate a shared sbitmap per tagset")
Reported-by: Yanhui Ma <yama@redhat.com>
Cc: John Garry <john.garry@huawei.com>
Cc: Hannes Reinecke <hare@suse.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: John Garry <john.garry@huawei.com>
Link: https://lore.kernel.org/r/20210406031933.767228-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
block: fix comment and add lockdep assert 2020-10-09T18:34:06+00:00 Yufen Yu yuyufen@huawei.com 2020-10-09T03:26:31+00:00 f0c6ae09db1d39cbcf35776f889e0f7f861493d2 After commit b89f625e28d4 ("block: don't release queue's sysfs lock during switching elevator"), whole elevator register and unregister function are covered by sysfs_lock. So, remove wrong comment and add lockdep assert. Signed-off-by: Yufen Yu <yuyufen@huawei.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> 
After commit b89f625e28d4 ("block: don't release queue's sysfs
lock during switching elevator"), whole elevator register and
unregister function are covered by sysfs_lock. So, remove wrong
comment and add lockdep assert.

Signed-off-by: Yufen Yu <yuyufen@huawei.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
block: use helper function to test queue register 2020-10-09T18:34:06+00:00 Yufen Yu yuyufen@huawei.com 2020-10-09T03:26:29+00:00 75e6c00fc75c53577bfc4831d909162c56e799ce We have defined common interface blk_queue_registered() to test QUEUE_FLAG_REGISTERED. Just use it. Signed-off-by: Yufen Yu <yuyufen@huawei.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> 
We have defined common interface blk_queue_registered() to
test QUEUE_FLAG_REGISTERED. Just use it.

Signed-off-by: Yufen Yu <yuyufen@huawei.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
block: remove redundant mq check 2020-10-09T18:34:06+00:00 Yufen Yu yuyufen@huawei.com 2020-10-09T03:26:28+00:00 6251b754f5b29d44d088cc73f508d15ddfb8d978 elv_support_iosched() will check queue_is_mq() for us. So, remove the redundant check to clean code. Signed-off-by: Yufen Yu <yuyufen@huawei.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> 
elv_support_iosched() will check queue_is_mq() for us. So, remove
the redundant check to clean code.

Signed-off-by: Yufen Yu <yuyufen@huawei.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>