From: Jens Axboe <axboe@kernel.dk>
To: Pankaj Raghav <p.raghav@samsung.com>,
Damien Le Moal <damien.lemoal@opensource.wdc.com>
Cc: linux-block@vger.kernel.org, linux-scsi@vger.kernel.org,
linux-nvme@lists.infradead.org, joshi.k@samsung.com,
Pankaj Raghav <pankydev8@gmail.com>,
Bart Van Assche <bvanassche@acm.org>
Subject: Re: [PATCH 1/5] block: enable batched allocation for blk_mq_alloc_request()
Date: Sat, 24 Sep 2022 08:44:53 -0600 [thread overview]
Message-ID: <3048caf9-3f67-d198-225e-6c7efc8aa373@kernel.dk> (raw)
In-Reply-To: <59e40929-bc1e-5d1e-3dcf-b9ba39b3d393@samsung.com>
On 9/24/22 5:56 AM, Pankaj Raghav wrote:
>>>> As the passthrough path can now support request caching via blk_mq_alloc_request(),
>>>> and it uses blk_execute_rq_nowait(), bad things can happen at least for zoned
>>>> devices:
>>>>
>>>> static inline struct blk_plug *blk_mq_plug( struct bio *bio)
>>>> {
>>>> /* Zoned block device write operation case: do not plug the BIO */
>>>> if (bdev_is_zoned(bio->bi_bdev) && op_is_write(bio_op(bio)))
>>>> return NULL;
>>>> ..
>>>
>>> Thinking more about it, even this will not fix it because op is
>>> REQ_OP_DRV_OUT if it is a NVMe write for passthrough requests.
>>>
>>> @Damien Should the condition in blk_mq_plug() be changed to:
>>>
>>> static inline struct blk_plug *blk_mq_plug( struct bio *bio)
>>> {
>>> /* Zoned block device write operation case: do not plug the BIO */
>>> if (bdev_is_zoned(bio->bi_bdev) && !op_is_read(bio_op(bio)))
>>> return NULL;
>>
>> That looks reasonable to me. It'll prevent plug optimizations even
>> for passthrough on zoned devices, but that's probably fine.
>>
>
> Do you want me send a separate patch for this change or you will fold it in
> the existing series?
Probably cleaner as a separate patch, would be great if you could
send one.
--
Jens Axboe
next prev parent reply other threads:[~2022-09-24 14:45 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-22 18:28 [PATCHSET 0/5] Enable alloc caching and batched freeing for passthrough Jens Axboe
2022-09-22 18:28 ` [PATCH 1/5] block: enable batched allocation for blk_mq_alloc_request() Jens Axboe
2022-09-23 14:52 ` Pankaj Raghav
2022-09-23 15:13 ` Pankaj Raghav
2022-09-23 20:54 ` Jens Axboe
2022-09-24 0:59 ` Damien Le Moal
2022-09-24 1:01 ` Jens Axboe
2022-09-24 1:22 ` Damien Le Moal
2022-09-24 11:56 ` Pankaj Raghav
2022-09-24 14:44 ` Jens Axboe [this message]
2022-09-22 18:28 ` [PATCH 2/5] block: change request end_io handler to pass back a return value Jens Axboe
2022-09-22 18:28 ` [PATCH 3/5] block: allow end_io based requests in the completion batch handling Jens Axboe
2022-09-22 18:28 ` [PATCH 4/5] nvme: split out metadata vs non metadata end_io uring_cmd completions Jens Axboe
2022-09-23 15:21 ` Christoph Hellwig
2022-09-23 20:52 ` Jens Axboe
2022-09-26 14:41 ` Christoph Hellwig
2022-09-26 14:41 ` Jens Axboe
2022-09-26 14:43 ` Christoph Hellwig
2022-09-26 14:50 ` Jens Axboe
2022-09-26 14:52 ` Christoph Hellwig
2022-09-26 14:54 ` Jens Axboe
2022-09-22 18:28 ` [PATCH 5/5] nvme: enable batched completions of passthrough IO Jens Axboe
2022-09-23 15:16 ` [PATCHSET 0/5] Enable alloc caching and batched freeing for passthrough Christoph Hellwig
2022-09-23 15:19 ` Jens Axboe
2022-09-23 15:21 ` Christoph Hellwig
2022-09-23 15:22 ` Jens Axboe
-- strict thread matches above, loose matches on Subject: below --
2022-09-27 1:44 [PATCHSET v2 " Jens Axboe
2022-09-27 1:44 ` [PATCH 1/5] block: enable batched allocation for blk_mq_alloc_request() Jens Axboe
2022-09-28 13:38 ` Anuj gupta
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