From: Christoph Hellwig <hch@infradead.org>
To: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Cc: Jens Axboe <axboe@kernel.dk>,
Christoph Hellwig <hch@infradead.org>,
linux-block <linux-block@vger.kernel.org>,
Damien Le Moal <Damien.LeMoal@wdc.com>,
Keith Busch <kbusch@kernel.org>,
"linux-scsi @ vger . kernel . org" <linux-scsi@vger.kernel.org>,
"Martin K . Petersen" <martin.petersen@oracle.com>
Subject: Re: [PATCH 08/11] block: delay un-dispatchable request
Date: Tue, 10 Mar 2020 09:45:23 -0700 [thread overview]
Message-ID: <20200310164523.GF15878@infradead.org> (raw)
In-Reply-To: <20200310094653.33257-9-johannes.thumshirn@wdc.com>
On Tue, Mar 10, 2020 at 06:46:50PM +0900, Johannes Thumshirn wrote:
> When a LLDD can't dispatch a request to a specific zone, it will return
> BLK_STS_ZONE_RESOURCE indicating this request needs to be delayed, e.g.
> because the zone it will be dispatched to is still write-locked.
>
> If this happens set the request aside in a local list to continue trying
> dispatching requests such as READ requests or a WRITE/ZONE_APPEND
> requests targetting other zones. This way we can still keep a high queue
> depth without starving other requests even if one request can't be
> served due to zone write-locking.
>
> All requests put aside in the local list due to BLK_STS_ZONE_RESOURCE
> are placed back at the head of the dispatch list for retrying the next
> time the device queues are run again.
This needs to go into the main zone append patch. Also I think some
of the above explanation would be useful in comments in the code.
next prev parent reply other threads:[~2020-03-10 16:45 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-10 9:46 [PATCH 00/11] Introduce Zone Append for writing to zoned block devices Johannes Thumshirn
2020-03-10 9:46 ` [PATCH 01/11] block: provide fallbacks for blk_queue_zone_is_seq and blk_queue_zone_no Johannes Thumshirn
2020-03-10 9:46 ` [PATCH 02/11] block: Introduce REQ_OP_ZONE_APPEND Johannes Thumshirn
2020-03-10 9:46 ` [PATCH 03/11] block: introduce bio_add_append_page Johannes Thumshirn
2020-03-10 16:43 ` Christoph Hellwig
2020-03-11 18:11 ` Johannes Thumshirn
2020-03-10 9:46 ` [PATCH 04/11] null_blk: Support REQ_OP_ZONE_APPEND Johannes Thumshirn
2020-03-10 16:43 ` Christoph Hellwig
2020-03-10 9:46 ` [PATCH 05/11] block: introduce BLK_STS_ZONE_RESOURCE Johannes Thumshirn
2020-03-10 16:43 ` Christoph Hellwig
2020-03-10 9:46 ` [PATCH 06/11] block: introduce blk_req_zone_write_trylock Johannes Thumshirn
2020-03-10 9:46 ` [PATCH 07/11] block: factor out requeue handling from dispatch code Johannes Thumshirn
2020-03-10 16:44 ` Christoph Hellwig
2020-03-10 9:46 ` [PATCH 08/11] block: delay un-dispatchable request Johannes Thumshirn
2020-03-10 16:45 ` Christoph Hellwig [this message]
2020-03-10 9:46 ` [PATCH 09/11] block: Introduce zone write pointer offset caching Johannes Thumshirn
2020-03-10 16:46 ` Christoph Hellwig
2020-03-11 0:34 ` Damien Le Moal
2020-03-11 6:24 ` Christoph Hellwig
2020-03-11 6:40 ` Damien Le Moal
2020-03-10 9:46 ` [PATCH 10/11] scsi: sd_zbc: factor out sanity checks for zoned commands Johannes Thumshirn
2020-03-10 9:46 ` [PATCH 11/11] scsi: sd_zbc: emulate ZONE_APPEND commands Johannes Thumshirn
2020-03-10 17:43 ` kbuild test robot
2020-03-10 19:38 ` kbuild test robot
2020-03-10 22:43 ` kbuild test robot
2020-03-10 23:04 ` kbuild test robot
2020-03-11 0:57 ` kbuild test robot
2020-03-10 16:42 ` [PATCH 00/11] Introduce Zone Append for writing to zoned block devices Christoph Hellwig
2020-03-11 0:37 ` Damien Le Moal
2020-03-11 6:24 ` Christoph Hellwig
2020-03-11 6:40 ` Damien Le Moal
2020-03-11 7:22 ` Johannes Thumshirn
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