From: Jens Axboe <axboe@fb.com>
To: Paolo Valente <paolo.valente@linaro.org>
Cc: Jens Axboe <axboe@kernel.dk>,
linux-block@vger.kernel.org,
Linux-Kernal <linux-kernel@vger.kernel.org>,
osandov@fb.com
Subject: Re: [PATCH 7/8] mq-deadline: add blk-mq adaptation of the deadline IO scheduler
Date: Thu, 2 Feb 2017 08:30:35 -0700 [thread overview]
Message-ID: <f26b60aa-b047-d7a3-550d-5270c696e2a1@fb.com> (raw)
In-Reply-To: <4C7AD847-C02D-47FF-83B7-F0BB8FBED5F5@linaro.org>
On 02/02/2017 02:19 AM, Paolo Valente wrote:
> The scheme is clear. One comment, in case it could make sense and
> avoid more complexity: since put_rq_priv is invoked in two different
> contexts, process or interrupt, I didn't feel so confusing that, when
> put_rq_priv is invoked in the context where the lock cannot be held
> (unless one is willing to pay with irq disabling all the times), the
> lock is not held, while, when invoked in the context where the lock
> can be held, the lock is actually held, or must be taken.
If you grab the same lock from put_rq_priv, yes, you must make it IRQ
disabling in all contexts, and use _irqsave() from put_rq_priv. If it's
just freeing resources, you could potentially wait and do that when
someone else needs them, since that part will come from proces context.
That would need two locks, though.
As I said above, I would not worry about the IRQ disabling lock.
--
Jens Axboe
WARNING: multiple messages have this Message-ID (diff)
From: Jens Axboe <axboe@fb.com>
To: Paolo Valente <paolo.valente@linaro.org>
Cc: Jens Axboe <axboe@kernel.dk>, <linux-block@vger.kernel.org>,
Linux-Kernal <linux-kernel@vger.kernel.org>, <osandov@fb.com>
Subject: Re: [PATCH 7/8] mq-deadline: add blk-mq adaptation of the deadline IO scheduler
Date: Thu, 2 Feb 2017 08:30:35 -0700 [thread overview]
Message-ID: <f26b60aa-b047-d7a3-550d-5270c696e2a1@fb.com> (raw)
In-Reply-To: <4C7AD847-C02D-47FF-83B7-F0BB8FBED5F5@linaro.org>
On 02/02/2017 02:19 AM, Paolo Valente wrote:
> The scheme is clear. One comment, in case it could make sense and
> avoid more complexity: since put_rq_priv is invoked in two different
> contexts, process or interrupt, I didn't feel so confusing that, when
> put_rq_priv is invoked in the context where the lock cannot be held
> (unless one is willing to pay with irq disabling all the times), the
> lock is not held, while, when invoked in the context where the lock
> can be held, the lock is actually held, or must be taken.
If you grab the same lock from put_rq_priv, yes, you must make it IRQ
disabling in all contexts, and use _irqsave() from put_rq_priv. If it's
just freeing resources, you could potentially wait and do that when
someone else needs them, since that part will come from proces context.
That would need two locks, though.
As I said above, I would not worry about the IRQ disabling lock.
--
Jens Axboe
next prev parent reply other threads:[~2017-02-02 15:30 UTC|newest]
Thread overview: 115+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-17 0:12 [PATCHSET v4] blk-mq-scheduling framework Jens Axboe
2016-12-17 0:12 ` [PATCH 1/8] block: move existing elevator ops to union Jens Axboe
2016-12-17 0:12 ` [PATCH 2/8] blk-mq: make mq_ops a const pointer Jens Axboe
2016-12-17 0:12 ` [PATCH 3/8] block: move rq_ioc() to blk.h Jens Axboe
2016-12-20 10:12 ` Paolo Valente
2016-12-20 10:12 ` Paolo Valente
2016-12-20 15:46 ` Jens Axboe
2016-12-20 22:14 ` Jens Axboe
2016-12-17 0:12 ` [PATCH 4/8] blk-mq: un-export blk_mq_free_hctx_request() Jens Axboe
2016-12-17 0:12 ` [PATCH 5/8] blk-mq: export some helpers we need to the scheduling framework Jens Axboe
2016-12-17 0:12 ` [PATCH 6/8] blk-mq-sched: add framework for MQ capable IO schedulers Jens Axboe
2016-12-20 11:55 ` Paolo Valente
2016-12-20 11:55 ` Paolo Valente
2016-12-20 15:45 ` Jens Axboe
2016-12-21 2:22 ` Jens Axboe
2016-12-22 15:20 ` Paolo Valente
2016-12-22 15:20 ` Paolo Valente
2016-12-22 9:59 ` Paolo Valente
2016-12-22 9:59 ` Paolo Valente
2016-12-22 11:13 ` Paolo Valente
2016-12-22 11:13 ` Paolo Valente
2017-01-17 2:47 ` Jens Axboe
2017-01-17 2:47 ` Jens Axboe
2017-01-17 10:13 ` Paolo Valente
2017-01-17 10:13 ` Paolo Valente
2017-01-17 12:38 ` Jens Axboe
2017-01-17 12:38 ` Jens Axboe
2016-12-23 10:12 ` Paolo Valente
2016-12-23 10:12 ` Paolo Valente
2017-01-17 2:47 ` Jens Axboe
2017-01-17 9:17 ` Paolo Valente
2017-01-17 9:17 ` Paolo Valente
2016-12-17 0:12 ` [PATCH 7/8] mq-deadline: add blk-mq adaptation of the deadline IO scheduler Jens Axboe
2016-12-20 9:34 ` Paolo Valente
2016-12-20 9:34 ` Paolo Valente
2016-12-20 15:46 ` Jens Axboe
2016-12-21 11:59 ` Bart Van Assche
2016-12-21 11:59 ` Bart Van Assche
2016-12-21 14:22 ` Jens Axboe
2016-12-22 16:07 ` Paolo Valente
2016-12-22 16:07 ` Paolo Valente
2017-01-17 2:47 ` Jens Axboe
2017-01-17 2:47 ` Jens Axboe
2016-12-22 16:49 ` Paolo Valente
2016-12-22 16:49 ` Paolo Valente
2017-01-17 2:47 ` Jens Axboe
2017-01-20 11:07 ` Paolo Valente
2017-01-20 11:07 ` Paolo Valente
2017-01-20 14:26 ` Jens Axboe
2017-01-20 13:14 ` Paolo Valente
2017-01-20 13:14 ` Paolo Valente
2017-01-20 13:18 ` Paolo Valente
2017-01-20 13:18 ` Paolo Valente
2017-01-20 14:28 ` Jens Axboe
2017-01-20 14:28 ` Jens Axboe
2017-02-01 11:11 ` Paolo Valente
2017-02-01 11:11 ` Paolo Valente
2017-02-02 5:19 ` Jens Axboe
2017-02-02 9:19 ` Paolo Valente
2017-02-02 9:19 ` Paolo Valente
2017-02-02 15:30 ` Jens Axboe [this message]
2017-02-02 15:30 ` Jens Axboe
2017-02-02 21:15 ` Paolo Valente
2017-02-02 21:15 ` Paolo Valente
2017-02-02 21:32 ` Jens Axboe
2017-02-02 21:32 ` Jens Axboe
2017-02-07 17:27 ` Paolo Valente
2017-02-07 17:27 ` Paolo Valente
2017-02-01 11:56 ` Paolo Valente
2017-02-01 11:56 ` Paolo Valente
2017-02-02 5:20 ` Jens Axboe
2017-02-16 10:46 ` Paolo Valente
2017-02-16 10:46 ` Paolo Valente
2017-02-16 15:35 ` Jens Axboe
2017-02-16 15:35 ` Jens Axboe
2016-12-17 0:12 ` [PATCH 8/8] blk-mq-sched: allow setting of default " Jens Axboe
2016-12-19 11:32 ` [PATCHSET v4] blk-mq-scheduling framework Paolo Valente
2016-12-19 11:32 ` Paolo Valente
2016-12-19 15:20 ` Jens Axboe
2016-12-19 15:20 ` Jens Axboe
2016-12-19 15:33 ` Jens Axboe
2016-12-19 18:21 ` Paolo Valente
2016-12-19 18:21 ` Paolo Valente
2016-12-19 21:05 ` Jens Axboe
2016-12-19 21:05 ` Jens Axboe
2016-12-22 15:28 ` Paolo Valente
2016-12-22 15:28 ` Paolo Valente
2017-01-17 2:47 ` Jens Axboe
2017-01-17 10:43 ` Paolo Valente
2017-01-17 10:44 ` Paolo Valente
2017-01-17 10:47 ` Paolo Valente
2017-01-17 10:49 ` Paolo Valente
2017-01-17 10:49 ` Paolo Valente
2017-01-18 16:14 ` Paolo Valente
2017-01-18 16:14 ` Paolo Valente
2017-01-18 16:21 ` Jens Axboe
2017-01-18 16:21 ` Jens Axboe
2017-01-23 17:04 ` Paolo Valente
2017-01-23 17:04 ` Paolo Valente
2017-01-23 17:42 ` Jens Axboe
2017-01-23 17:42 ` Jens Axboe
2017-01-25 8:46 ` Paolo Valente
2017-01-25 8:46 ` Paolo Valente
2017-01-25 16:13 ` Jens Axboe
2017-01-25 16:13 ` Jens Axboe
2017-01-26 14:23 ` Paolo Valente
2017-01-26 14:23 ` Paolo Valente
2016-12-22 16:23 ` Bart Van Assche
2016-12-22 16:52 ` Omar Sandoval
2016-12-22 16:52 ` Omar Sandoval
2016-12-22 16:57 ` Bart Van Assche
2016-12-22 16:57 ` Bart Van Assche
2016-12-22 17:12 ` Omar Sandoval
2016-12-22 17:39 ` Bart Van Assche
2016-12-22 17:39 ` Bart Van Assche
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