From: Mike Snitzer <snitzer@redhat.com>
To: Jens Axboe <axboe@fb.com>
Cc: linux-kernel@vger.kernel.org, hch@lst.de
Subject: Re: [PATCH 2/2] block: make /sys/block/<dev>/queue/discard_max_bytes writeable
Date: Tue, 14 Jul 2015 11:23:32 -0400 [thread overview]
Message-ID: <20150714152332.GA5568@redhat.com> (raw)
In-Reply-To: <1436886139-18673-3-git-send-email-axboe@fb.com>
On Tue, Jul 14 2015 at 11:02am -0400,
Jens Axboe <axboe@fb.com> wrote:
> Lots of devices support huge discard sizes these days. Depending
> on how the device handles them internally, huge discards can
> introduce massive latencies (hundreds of msec) on the device side.
>
> We have a sysfs file, discard_max_bytes, that advertises the max
> hardware supported discard size. Make this writeable, and split
> the settings into a soft and hard limit. This can be set from
> 'discard_granularity' and up to the hardware limit.
Looks pretty good, but we'll lose the original discard_max_bytes once it
is changed. That information loss will prevent users from knowing what
adjustments are possible over time.
This may be OK, but figured i'd raise it.
next prev parent reply other threads:[~2015-07-14 15:23 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-14 15:02 [PATCH 0/2] Configurable max discard size Jens Axboe
2015-07-14 15:02 ` [PATCH 1/2] block: have drivers use blk_queue_max_discard_sectors() Jens Axboe
2015-07-14 15:02 ` [PATCH 2/2] block: make /sys/block/<dev>/queue/discard_max_bytes writeable Jens Axboe
2015-07-14 15:23 ` Mike Snitzer [this message]
2015-07-14 15:29 ` Jens Axboe
2015-07-14 16:01 ` [PATCH 0/2] Configurable max discard size Christoph Hellwig
2015-07-14 16:04 ` Jens Axboe
2015-07-14 17:53 ` Christoph Hellwig
2015-07-14 18:36 ` Jens Axboe
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=20150714152332.GA5568@redhat.com \
--to=snitzer@redhat.com \
--cc=axboe@fb.com \
--cc=hch@lst.de \
--cc=linux-kernel@vger.kernel.org \
/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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox