From: Damien Le Moal <damien.lemoal@opensource.wdc.com>
To: Bart Van Assche <bvanassche@acm.org>, Jens Axboe <axboe@kernel.dk>
Cc: linux-block@vger.kernel.org, linux-scsi@vger.kernel.org,
Christoph Hellwig <hch@lst.de>,
Adrian Hunter <adrian.hunter@intel.com>,
Avri Altman <avri.altman@wdc.com>, Ming Lei <ming.lei@redhat.com>,
Chaitanya Kulkarni <kch@nvidia.com>
Subject: Re: [PATCH v2 8/8] null_blk: Support configuring the maximum segment size
Date: Thu, 1 Dec 2022 09:39:10 +0900 [thread overview]
Message-ID: <687161b4-3e92-9fbf-c0a6-e8dceee3d250@opensource.wdc.com> (raw)
In-Reply-To: <6c41f85b-7add-60d7-e131-71c3cfae80d0@acm.org>
On 12/1/22 07:29, Bart Van Assche wrote:
> On 11/23/22 17:40, Damien Le Moal wrote:
>> On 11/24/22 05:57, Bart Van Assche wrote:
>>> +static unsigned int g_max_segment_size = 1UL << 31;
>>
>> 1UL is unsigned long be this var is unsigned int. Why not simply use
>> UINT_MAX here ? You prefer the 2GB value ? If yes, then may be at least
>> change that to "1U << 31", no ?
>>
>> [ ... ]
>>> @@ -2106,6 +2119,7 @@ static int null_add_dev(struct nullb_device *dev)
>>> dev->max_sectors = min_t(unsigned int, dev->max_sectors,
>>> BLK_DEF_MAX_SECTORS);
>>> blk_queue_max_hw_sectors(nullb->q, dev->max_sectors);
>>> + blk_queue_max_segment_size(nullb->q, dev->max_segment_size);
>>
>> Should we keep the ability to use the kernel default value as the default
>> here ?
>> E.g.
>>
>> if (dev->max_segment_size)
>> blk_queue_max_segment_size(nullb->q,
>> dev->max_segment_size);
>>
>> If yes, then g_max_segment_size initial value should be 0, meaning "kernel
>> default".
>
> Hi Damien,
>
> How about changing the default value for g_max_segment_size from
> 1UL << 31 into BLK_MAX_SEGMENT_SIZE? That will simplify the code and
> also prevents that this patch changes the behavior of the null_blk
> driver if g_max_segment_size is not modified by the user.
Sounds good to me.
>
> Thanks,
>
> Bart.
>
--
Damien Le Moal
Western Digital Research
prev parent reply other threads:[~2022-12-01 0:39 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-23 20:57 [PATCH v2 0/8] Add support for segments smaller than one page Bart Van Assche
2022-11-23 20:57 ` [PATCH v2 1/8] block: Introduce CONFIG_BLK_SUB_PAGE_SEGMENTS and QUEUE_FLAG_SUB_PAGE_SEGMENTS Bart Van Assche
2022-11-23 20:57 ` [PATCH v2 2/8] block: Support configuring limits below the page size Bart Van Assche
2022-11-23 20:57 ` [PATCH v2 3/8] block: Support submitting passthrough requests with small segments Bart Van Assche
2022-11-23 20:57 ` [PATCH v2 4/8] block: Add support for filesystem requests and " Bart Van Assche
2022-11-23 20:57 ` [PATCH v2 5/8] block: Add support for small segments in blk_rq_map_user_iov() Bart Van Assche
2022-11-23 20:57 ` [PATCH v2 6/8] scsi: core: Set the SUB_PAGE_SEGMENTS request queue flag Bart Van Assche
2022-11-23 20:57 ` [PATCH v2 7/8] scsi_debug: Support configuring the maximum segment size Bart Van Assche
2022-11-25 17:34 ` Douglas Gilbert
2022-11-30 22:30 ` Bart Van Assche
2022-11-23 20:57 ` [PATCH v2 8/8] null_blk: " Bart Van Assche
2022-11-24 1:40 ` Damien Le Moal
2022-11-30 22:29 ` Bart Van Assche
2022-12-01 0:39 ` Damien Le Moal [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=687161b4-3e92-9fbf-c0a6-e8dceee3d250@opensource.wdc.com \
--to=damien.lemoal@opensource.wdc.com \
--cc=adrian.hunter@intel.com \
--cc=avri.altman@wdc.com \
--cc=axboe@kernel.dk \
--cc=bvanassche@acm.org \
--cc=hch@lst.de \
--cc=kch@nvidia.com \
--cc=linux-block@vger.kernel.org \
--cc=linux-scsi@vger.kernel.org \
--cc=ming.lei@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.