From: Damien Le Moal <damien.lemoal@opensource.wdc.com>
To: Bart Van Assche <bvanassche@acm.org>, Christoph Hellwig <hch@lst.de>
Cc: Ming Lei <ming.lei@redhat.com>, Jens Axboe <axboe@kernel.dk>,
linux-block@vger.kernel.org, Jaegeuk Kim <jaegeuk@kernel.org>,
Jan Kara <jack@suse.cz>,
Johannes Thumshirn <johannes.thumshirn@wdc.com>
Subject: Re: [PATCH 2/2] block: Split and submit bios in LBA order
Date: Sun, 26 Mar 2023 10:45:08 +0900 [thread overview]
Message-ID: <5b450fee-714b-224e-69ae-497633e005ed@opensource.wdc.com> (raw)
In-Reply-To: <7f4463c1-fd02-8ac5-16d7-61ffe6279e07@acm.org>
On 3/26/23 01:31, Bart Van Assche wrote:
> On 3/24/23 19:00, Damien Le Moal wrote:
>> The trick here could be to have the UFS LLD to unlock the target zone of a write
>> when the command is sent to the device, instead of when the command completes.
>> This way, the zone is still locked when there is a requeue and there is no
>> reordering. That could allow for write qd > 1 in the case of UFS. And this
>> method could actually work for regular writes too.
>
> Hi Damien,
>
> Although the above sounds interesting to me, I think the following two
> scenarios are not handled by the above approach and can lead to reordering:
> * The SCSI device reporting a unit attention.
> * The SCSI device responding with the SCSI status "BUSY". The UFS
> standard explicitly allows this. From the UFS standard: "If the unit is
> not ready to accept a new command (e.g., still processing previous
> command) a STATUS response of BUSY will be returned."
Yes, that likely would be an issue for regular writes, but likely not for zone
append emulation using regular writes though, since a "busy" return for a ZA
emulated regular write can be resent later with a different aligned write location.
--
Damien Le Moal
Western Digital Research
next prev parent reply other threads:[~2023-03-26 1:45 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-17 19:59 [PATCH 0/2] Submit split bios in LBA order Bart Van Assche
2023-03-17 19:59 ` [PATCH 1/2] block: Split blk_recalc_rq_segments() Bart Van Assche
2023-03-18 6:38 ` Christoph Hellwig
2023-03-17 19:59 ` [PATCH 2/2] block: Split and submit bios in LBA order Bart Van Assche
2023-03-17 22:28 ` Jan Kara
2023-03-18 6:33 ` Christoph Hellwig
2023-03-17 23:38 ` Ming Lei
2023-03-17 23:45 ` Bart Van Assche
2023-03-20 23:28 ` Ming Lei
2023-03-20 23:32 ` Bart Van Assche
2023-03-21 0:44 ` Ming Lei
2023-03-21 1:46 ` Damien Le Moal
2023-03-21 2:17 ` Ming Lei
2023-03-21 3:24 ` Damien Le Moal
2023-03-21 8:00 ` Ming Lei
2023-03-21 8:51 ` Damien Le Moal
2023-03-21 9:09 ` Christoph Hellwig
2023-03-21 9:50 ` Damien Le Moal
2023-03-21 5:55 ` Christoph Hellwig
2023-03-21 14:36 ` Bart Van Assche
2023-03-23 8:26 ` Christoph Hellwig
2023-03-23 10:28 ` Damien Le Moal
2023-03-23 16:27 ` Bart Van Assche
2023-03-23 22:53 ` Damien Le Moal
2023-03-24 16:55 ` Bart Van Assche
2023-03-25 2:00 ` Damien Le Moal
2023-03-25 16:31 ` Bart Van Assche
2023-03-26 1:45 ` Damien Le Moal [this message]
2023-03-26 23:45 ` Christoph Hellwig
2023-03-27 21:06 ` Bart Van Assche
2023-03-27 23:43 ` Christoph Hellwig
2023-04-06 20:30 ` Bart Van Assche
2023-03-27 21:20 ` Bart Van Assche
2023-03-18 6:42 ` Christoph Hellwig
2023-03-18 6:29 ` [PATCH 0/2] Submit split " Christoph Hellwig
2023-03-20 17:22 ` Bart Van Assche
2023-03-20 21:06 ` Khazhy Kumykov
2023-03-23 8:27 ` Christoph Hellwig
2023-03-24 17:05 ` Bart Van Assche
2023-03-25 2:15 ` Damien Le Moal
2023-03-26 23:42 ` Christoph Hellwig
2023-03-26 23:44 ` Christoph Hellwig
2023-04-06 20:32 ` Bart Van Assche
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