From: Kent Overstreet <kent.overstreet@gmail.com>
To: Ming Lei <ming.lei@canonical.com>
Cc: Jens Axboe <axboe@fb.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-block@vger.kernel.org,
Christoph Hellwig <hch@infradead.org>,
Eric Wheeler <bcache@lists.ewheeler.net>,
Sebastian Roesner <sroesner-kernelorg@roesner-online.de>,
"4.2+" <stable@vger.kernel.org>, Shaohua Li <shli@fb.com>
Subject: Re: [PATCH] block: make sure big bio is splitted into at most 256 bvecs
Date: Tue, 5 Apr 2016 18:40:31 -0800 [thread overview]
Message-ID: <20160406024031.GB7793@kmo-pixel> (raw)
In-Reply-To: <CACVXFVPD=fb3iFwY9xO7s_daZ-gePiXKQs7XEO48vCGx+WSOzg@mail.gmail.com>
On Wed, Apr 06, 2016 at 10:37:05AM +0800, Ming Lei wrote:
> On Wed, Apr 6, 2016 at 10:34 AM, Kent Overstreet
> <kent.overstreet@gmail.com> wrote:
> > On Wed, Apr 06, 2016 at 10:30:22AM +0800, Ming Lei wrote:
> >> Now limit.max_segments is for limiting segments from hw view, one this
> >> segment may include lots of pages/bvecs.
> >>
> >> The current bio_clone() issue is that we can't clone from one bio which
> >> includes more than 256 bvecs, maybe all these 256 bvecs belong to
> >> one same hw segment.
> >
> > So the distinction is purely a post multipage bvec thing?
>
> Even after multipage bvec is applied, the limit for max bvecs is still needed
> for some cases like bio bounce, in which bio_clone() need to
> clone single page bvec.
s/max bvecs/max pages/?
What I meant is that until we have multipage bvecs, unless I'm missing something
max_segments is exactly what we want. After multipage bvecs, things do get more
complicated I agree.
next prev parent reply other threads:[~2016-04-06 2:40 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-05 17:44 [PATCH] block: make sure big bio is splitted into at most 256 bvecs Ming Lei
2016-04-05 18:27 ` Shaohua Li
2016-04-06 0:27 ` Kent Overstreet
2016-04-06 0:30 ` Shaohua Li
2016-04-06 0:36 ` Kent Overstreet
2016-04-06 0:41 ` Shaohua Li
2016-04-06 0:45 ` Kent Overstreet
2016-04-06 0:59 ` Shaohua Li
2016-04-06 1:05 ` Ming Lei
2016-04-06 0:47 ` Ming Lei
2016-04-06 1:04 ` Shaohua Li
2016-04-06 1:11 ` Ming Lei
2016-04-06 0:30 ` Kent Overstreet
2016-04-06 0:59 ` Ming Lei
2016-04-06 1:10 ` Kent Overstreet
2016-04-06 1:20 ` Ming Lei
2016-04-06 1:28 ` Kent Overstreet
2016-04-06 1:51 ` Ming Lei
2016-04-06 2:22 ` Kent Overstreet
2016-04-06 2:30 ` Ming Lei
2016-04-06 2:34 ` Kent Overstreet
2016-04-06 2:37 ` Ming Lei
2016-04-06 2:40 ` Kent Overstreet [this message]
2016-04-06 2:51 ` Ming Lei
2016-04-06 2:58 ` Kent Overstreet
2016-04-06 1:02 ` Ming Lei
2016-04-07 1:48 ` Eric Wheeler
2016-04-07 1:36 ` Eric Wheeler
2016-04-07 1:49 ` Ming Lei
2016-04-07 1:56 ` Eric Wheeler
2016-04-07 2:16 ` Ming Lei
2016-04-07 23:29 ` Eric Wheeler
2016-04-08 0:21 ` Ming Lei
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