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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: Tue, 20 Dec 2016 08:46:19 -0700	[thread overview]
Message-ID: <ae644260-2290-021f-24dc-4379766a4603@fb.com> (raw)
In-Reply-To: <99111D0B-F051-4D8F-94EF-E7962F47FFD9@linaro.org>

On 12/20/2016 02:34 AM, Paolo Valente wrote:
> 
>> Il giorno 17 dic 2016, alle ore 01:12, Jens Axboe <axboe@fb.com> ha scritto:
>>
>> This is basically identical to deadline-iosched, except it registers
>> as a MQ capable scheduler. This is still a single queue design.
>>
>> Signed-off-by: Jens Axboe <axboe@fb.com>
>> ...
>> +
>> +static bool dd_has_work(struct blk_mq_hw_ctx *hctx)
>> +{
>> +	struct deadline_data *dd = hctx->queue->elevator->elevator_data;
>> +
>> +	return !list_empty_careful(&dd->dispatch) ||
>> +		!list_empty_careful(&dd->fifo_list[0]) ||
>> +		!list_empty_careful(&dd->fifo_list[1]);
> 
> Just a request for clarification: if I'm not mistaken,
> list_empty_careful can be used safely only if the only possible other
> concurrent access is a delete.  Or am I missing something?

We can "solve" that with memory barriers. For now, it's safe to ignore
on your end.


-- 
Jens Axboe

  reply	other threads:[~2016-12-20 15:46 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 [this message]
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
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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