From: Christoph Hellwig <hch@lst.de>
To: Bart Van Assche <bvanassche@acm.org>
Cc: Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
linux-block@vger.kernel.org, Jaegeuk Kim <jaegeuk@kernel.org>,
Damien Le Moal <damien.lemoal@opensource.wdc.com>,
Ming Lei <ming.lei@redhat.com>
Subject: Re: [PATCH v3 2/9] block: Micro-optimize blk_req_needs_zone_write_lock()
Date: Mon, 1 May 2023 06:34:44 +0200 [thread overview]
Message-ID: <20230501043444.GA19847@lst.de> (raw)
In-Reply-To: <1c28f0b9-14f1-5fc1-4e15-52c4f6c2c91c@acm.org>
On Fri, Apr 28, 2023 at 12:46:06PM -0700, Bart Van Assche wrote:
>>> + if ((bio_op(bio) == REQ_OP_WRITE ||
>>> + bio_op(bio) == REQ_OP_WRITE_ZEROES) &&
>>> + disk_zone_is_seq(bio->bi_bdev->bd_disk, bio->bi_iter.bi_sector))
>>> return NULL;
>>
>> I find this a bit hard to hard to read. Why not:
>>
>> if (disk_zone_is_seq(bio->bi_bdev->bd_disk, bio->bi_iter.bi_sector)) {
>> /*
>> * Do not plug for writes that require zone locking.
>> */
>> if (bio_op(bio) == REQ_OP_WRITE ||
>> bio_op(bio) == REQ_OP_WRITE_ZEROES)
>> return NULL;
>> }
>
> In the above alternative the expensive check happens before a check that is not
> expensive at all. Do you really want me to call disk_zone_is_seq() before checking
> the operation type?
What expensive check? The first check in disk_zone_is_seq is for
a zoned device, avoiding any further check if it is not.
next prev parent reply other threads:[~2023-05-01 4:34 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-24 20:33 [PATCH v3 0/9] mq-deadline: Improve support for zoned block devices Bart Van Assche
2023-04-24 20:33 ` [PATCH v3 1/9] block: Simplify blk_req_needs_zone_write_lock() Bart Van Assche
2023-04-24 20:33 ` [PATCH v3 2/9] block: Micro-optimize blk_req_needs_zone_write_lock() Bart Van Assche
2023-04-28 5:44 ` Christoph Hellwig
2023-04-28 19:46 ` Bart Van Assche
2023-05-01 4:34 ` Christoph Hellwig [this message]
2023-04-24 20:33 ` [PATCH v3 3/9] block: Introduce blk_rq_is_seq_zoned_write() Bart Van Assche
2023-04-28 5:45 ` Christoph Hellwig
2023-04-28 19:59 ` Bart Van Assche
2023-04-24 20:33 ` [PATCH v3 4/9] block: mq-deadline: Clean up deadline_check_fifo() Bart Van Assche
2023-04-28 5:46 ` Christoph Hellwig
2023-04-24 20:33 ` [PATCH v3 5/9] block: mq-deadline: Simplify deadline_skip_seq_writes() Bart Van Assche
2023-04-28 5:47 ` Christoph Hellwig
2023-04-24 20:33 ` [PATCH v3 6/9] block: mq-deadline: Improve deadline_skip_seq_writes() Bart Van Assche
2023-04-28 5:48 ` Christoph Hellwig
2023-04-24 20:33 ` [PATCH v3 7/9] block: mq-deadline: Track the dispatch position Bart Van Assche
2023-04-28 5:50 ` Christoph Hellwig
2023-04-28 17:04 ` Bart Van Assche
2023-04-28 20:04 ` Bart Van Assche
2023-05-01 4:35 ` Christoph Hellwig
2023-04-24 20:33 ` [PATCH v3 8/9] block: mq-deadline: Handle requeued requests correctly Bart Van Assche
2023-04-28 5:54 ` Christoph Hellwig
2023-04-28 17:03 ` Bart Van Assche
2023-05-01 4:37 ` Christoph Hellwig
2023-04-24 20:33 ` [PATCH v3 9/9] block: mq-deadline: Fix handling of at-head zoned writes Bart Van Assche
2023-04-28 5:58 ` Christoph Hellwig
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