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From: Bart Van Assche <bvanassche@acm.org>
To: Damien Le Moal <Damien.LeMoal@wdc.com>, Jens Axboe <axboe@kernel.dk>
Cc: "linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
	Christoph Hellwig <hch@lst.de>, Jaegeuk Kim <jaegeuk@kernel.org>,
	Hannes Reinecke <hare@suse.de>, Ming Lei <ming.lei@redhat.com>,
	Johannes Thumshirn <Johannes.Thumshirn@wdc.com>,
	Himanshu Madhani <himanshu.madhani@oracle.com>
Subject: Re: [PATCH 04/14] block: Introduce the ioprio rq-qos policy
Date: Wed, 9 Jun 2021 09:48:59 -0700	[thread overview]
Message-ID: <98dbb3dc-d925-f2a8-7f34-94f9c56bb257@acm.org> (raw)
In-Reply-To: <DM6PR04MB708135D0C71D2042E6674E23E7369@DM6PR04MB7081.namprd04.prod.outlook.com>

On 6/8/21 9:40 PM, Damien Le Moal wrote:
> On 2021/06/09 8:07, Bart Van Assche wrote:

[ ... ]

>> +/*
>> + * The accepted I/O priority values are 0..IOPRIO_CLASS_MAX(3). 0 (default)
>> + * means do not modify the I/O priority. Values 1..3 are used to restrict the
>> + * I/O priority for a cgroup to the specified priority. See also
>> + * <linux/ioprio.h>.
>> + */
>> +#define IOPRIO_CLASS_MAX IOPRIO_CLASS_IDLE

[ ... ]

>> +static int ioprio_set_prio_class(struct cgroup_subsys_state *css,
>> +				 struct cftype *cft, u64 val)
>> +{
>> +	struct ioprio_blkcg *blkcg = ioprio_blkcg_from_css(css);
>> +
>> +	if (val > IOPRIO_CLASS_MAX)
>> +		return -EINVAL;
> 
> Where is IOPRIO_CLASS_MAX defined ? I do not see it.

Near the start of the new block/blk-ioprio.c file.

> Why not use ioprio_valid() ?

The definition of that macro is as follows:

#define ioprio_valid(mask)	\
	(IOPRIO_PRIO_CLASS((mask)) != IOPRIO_CLASS_NONE)

So that macro accepts I/O priority classes 1..7 while the above code
accepts I/O priority classes 0..3. I think that ioprio_set_prio_class()
should only accept I/O priority class values 0..3.

Thanks,

Bart.

  reply	other threads:[~2021-06-09 16:49 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-08 23:06 [PATCH 00/14] Improve I/O priority support Bart Van Assche
2021-06-08 23:06 ` [PATCH 01/14] block/Kconfig: Make the BLK_WBT and BLK_WBT_MQ entries consecutive Bart Van Assche
2021-06-09  4:14   ` Damien Le Moal
2021-06-09  7:03   ` Johannes Thumshirn
2021-06-10  6:02   ` Hannes Reinecke
2021-06-08 23:06 ` [PATCH 02/14] block/blk-cgroup: Swap the blk_throtl_init() and blk_iolatency_init() calls Bart Van Assche
2021-06-09  4:19   ` Damien Le Moal
2021-06-09  7:05   ` Johannes Thumshirn
2021-06-10  6:02   ` Hannes Reinecke
2021-06-08 23:06 ` [PATCH 03/14] block/blk-rq-qos: Move a function from a header file into a C file Bart Van Assche
2021-06-09  4:22   ` Damien Le Moal
2021-06-10  6:03   ` Hannes Reinecke
2021-06-08 23:06 ` [PATCH 04/14] block: Introduce the ioprio rq-qos policy Bart Van Assche
2021-06-09  4:40   ` Damien Le Moal
2021-06-09 16:48     ` Bart Van Assche [this message]
2021-06-10  0:29       ` Damien Le Moal
2021-06-10  6:20   ` Hannes Reinecke
2021-06-10 17:14     ` Bart Van Assche
2021-06-08 23:06 ` [PATCH 05/14] block/mq-deadline: Add several comments Bart Van Assche
2021-06-10  6:21   ` Hannes Reinecke
2021-06-08 23:06 ` [PATCH 06/14] block/mq-deadline: Add two lockdep_assert_held() statements Bart Van Assche
2021-06-10  6:21   ` Hannes Reinecke
2021-06-08 23:06 ` [PATCH 07/14] block/mq-deadline: Remove two local variables Bart Van Assche
2021-06-10  6:22   ` Hannes Reinecke
2021-06-08 23:06 ` [PATCH 08/14] block/mq-deadline: Rename dd_init_queue() and dd_exit_queue() Bart Van Assche
2021-06-08 23:06 ` [PATCH 09/14] block/mq-deadline: Improve compile-time argument checking Bart Van Assche
2021-06-08 23:06 ` [PATCH 10/14] block/mq-deadline: Improve the sysfs show and store macros Bart Van Assche
2021-06-09  4:46   ` Damien Le Moal
2021-06-09 16:54     ` Bart Van Assche
2021-06-10  0:31       ` Damien Le Moal
2021-06-09  7:11   ` Johannes Thumshirn
2021-06-09 16:59     ` Bart Van Assche
2021-06-10  6:23   ` Hannes Reinecke
2021-06-08 23:07 ` [PATCH 11/14] block/mq-deadline: Reserve 25% of scheduler tags for synchronous requests Bart Van Assche
2021-06-10  6:26   ` Hannes Reinecke
2021-06-08 23:07 ` [PATCH 12/14] block/mq-deadline: Add I/O priority support Bart Van Assche
2021-06-09  5:03   ` Damien Le Moal
2021-06-09 17:25     ` Bart Van Assche
2021-06-10  0:39       ` Damien Le Moal
2021-06-10  6:35   ` Hannes Reinecke
2021-06-08 23:07 ` [PATCH 13/14] block/mq-deadline: Add cgroup support Bart Van Assche
2021-06-10  6:37   ` Hannes Reinecke
2021-06-08 23:07 ` [PATCH 14/14] block/mq-deadline: Prioritize high-priority requests Bart Van Assche
2021-06-09  5:10   ` Damien Le Moal
2021-06-10  6:43   ` Hannes Reinecke

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