From: Ming Lei <ming.lei@redhat.com>
To: Nilay Shroff <nilay@linux.ibm.com>
Cc: "Jens Axboe" <axboe@kernel.dk>,
linux-block@vger.kernel.org,
"Shinichiro Kawasaki" <shinichiro.kawasaki@wdc.com>,
"Thomas Hellström" <thomas.hellstrom@linux.intel.com>,
"Christoph Hellwig" <hch@lst.de>
Subject: Re: [PATCH 13/15] block: remove several ->elevator_lock
Date: Mon, 14 Apr 2025 09:46:24 +0800 [thread overview]
Message-ID: <Z_xo8GwBAs8v6sfJ@fedora> (raw)
In-Reply-To: <567cb7ab-23d6-4cee-a915-c8cdac903ddd@linux.ibm.com>
On Fri, Apr 11, 2025 at 12:37:49AM +0530, Nilay Shroff wrote:
>
>
> On 4/10/25 7:00 PM, Ming Lei wrote:
> > Both blk_mq_map_swqueue() and blk_mq_realloc_hw_ctxs() are only called
> > from queue initialization or updating nr_hw_queues code, in which
> > elevator switch can't happen any more.
> >
> > So remove these ->elevator_lock uses.
> >
> But what if blk_mq_map_swqueue runs in parallel, one context from
> blk_mq_init_allocated_queue and another from blk_mq_update_nr_hw_queues?
> It seems this is possible due to blk_mq_map_swqueue is invoked right
> after queue is added in tag-set from blk_mq_init_allocated_queue.
Good catch, one simple fix is to swap blk_mq_add_queue_tag_set() with
blk_mq_map_swqueue() in blk_mq_init_allocated_queue() since blk_mq_map_swqueue
doesn't rely on BLK_MQ_F_TAG_QUEUE_SHARED.
Thanks,
Ming
next prev parent reply other threads:[~2025-04-14 1:46 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-04-10 13:30 [PATCH 00/15] block: unify elevator changing and fix lockdep warning Ming Lei
2025-04-10 13:30 ` [PATCH 01/15] block: don't call freeze queue in elevator_switch() and elevator_disable() Ming Lei
2025-04-10 13:30 ` [PATCH 02/15] block: add two helpers for registering/un-registering sched debugfs Ming Lei
2025-04-10 14:25 ` Christoph Hellwig
2025-04-10 13:30 ` [PATCH 03/15] block: move sched debugfs register into elvevator_register_queue Ming Lei
2025-04-10 14:27 ` Christoph Hellwig
2025-04-14 0:42 ` Ming Lei
2025-04-10 13:30 ` [PATCH 04/15] block: prevent elevator switch during updating nr_hw_queues Ming Lei
2025-04-10 14:36 ` Christoph Hellwig
2025-04-14 0:54 ` Ming Lei
2025-04-14 6:07 ` Christoph Hellwig
2025-04-15 2:03 ` Ming Lei
2025-04-11 19:13 ` Nilay Shroff
2025-04-14 0:55 ` Ming Lei
2025-04-10 13:30 ` [PATCH 05/15] block: simplify elevator reset for " Ming Lei
2025-04-10 14:40 ` Christoph Hellwig
2025-04-10 15:34 ` Christoph Hellwig
2025-04-14 0:58 ` Ming Lei
2025-04-14 6:09 ` Christoph Hellwig
2025-04-15 2:05 ` Ming Lei
2025-04-10 13:30 ` [PATCH 06/15] block: add helper of elevator_change() Ming Lei
2025-04-10 13:30 ` [PATCH 07/15] block: move blk_unregister_queue() & device_del() after freeze wait Ming Lei
2025-04-14 6:19 ` Christoph Hellwig
2025-04-15 2:26 ` Ming Lei
2025-04-10 13:30 ` [PATCH 08/15] block: add `struct elev_change_ctx` for unifying elevator change Ming Lei
2025-04-14 6:21 ` Christoph Hellwig
2025-04-10 13:30 ` [PATCH 09/15] block: " Ming Lei
2025-04-10 18:37 ` Nilay Shroff
2025-04-14 1:22 ` Ming Lei
2025-04-15 12:30 ` Nilay Shroff
2025-04-16 1:49 ` Ming Lei
2025-04-10 13:30 ` [PATCH 10/15] block: pass elevator_queue to elv_register_queue & unregister_queue Ming Lei
2025-04-14 6:22 ` Christoph Hellwig
2025-04-15 2:31 ` Ming Lei
2025-04-16 4:53 ` Christoph Hellwig
2025-04-10 13:30 ` [PATCH 11/15] block: move elv_register[unregister]_queue out of elevator_lock Ming Lei
2025-04-11 19:20 ` Nilay Shroff
2025-04-14 1:24 ` Ming Lei
2025-04-15 9:39 ` Nilay Shroff
2025-04-15 10:32 ` Ming Lei
2025-04-10 13:30 ` [PATCH 12/15] block: move debugfs/sysfs register out of freezing queue Ming Lei
2025-04-10 18:57 ` Nilay Shroff
2025-04-14 1:42 ` Ming Lei
2025-04-15 9:37 ` Nilay Shroff
2025-04-15 10:06 ` Ming Lei
2025-04-15 11:15 ` Nilay Shroff
2025-04-15 11:54 ` Ming Lei
2025-04-15 12:21 ` Nilay Shroff
2025-04-15 12:41 ` Ming Lei
2025-04-10 13:30 ` [PATCH 13/15] block: remove several ->elevator_lock Ming Lei
2025-04-10 19:07 ` Nilay Shroff
2025-04-14 1:46 ` Ming Lei [this message]
2025-04-10 13:30 ` [PATCH 14/15] block: move hctx cpuhp add/del out of queue freezing Ming Lei
2025-04-10 13:30 ` [PATCH 15/15] block: move wbt_enable_default() out of queue freezing from scheduler's ->exit() Ming Lei
2025-04-10 19:20 ` Nilay Shroff
2025-04-14 1:55 ` Ming Lei
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