From: Ming Lei <ming.lei@redhat.com>
To: Johannes Thumshirn <jthumshirn@suse.de>
Cc: Jens Axboe <axboe@fb.com>,
Linux Block Layer Mailinglist <linux-block@vger.kernel.org>,
Hannes Reinecke <hare@suse.de>,
Linux Kernel Mailinglist <linux-kernel@vger.kernel.org>,
Jan Kara <jack@suse.cz>, Sagi Grimberg <sagi@grimberg.me>
Subject: Re: [PATCH] block: respect virtual boundary mask in bvecs
Date: Mon, 5 Nov 2018 20:01:54 +0800 [thread overview]
Message-ID: <20181105120153.GD12367@ming.t460p> (raw)
In-Reply-To: <7c649b43-f952-cf94-93d6-44fb153acced@suse.de>
On Mon, Nov 05, 2018 at 12:50:50PM +0100, Johannes Thumshirn wrote:
> On 05/11/2018 11:55, Ming Lei wrote:
> > On Mon, Nov 05, 2018 at 11:23:01AM +0100, Johannes Thumshirn wrote:
> >> With drivers like iSer we are seeing a lot of bio splitting and smaller I/Os
> >> being submitted to the driver.
> >>
> >> The root cause of this issue that the virtual boundary mask code does not take
> >> into consideration that some of the memory segments in the SG list may have
> >> come from a huge memory page that is being managed in the SG list as 4K
> >
> > I guess you mean something like 64K PAGE_SIZE, instead of huge page.
>
> No I mean like a 2M page from an upper layer.
If you mean the real huge page, this patch shouldn't have made a difference
because bio_vec->bv_offset is in [0, PAGE_SIZE), and iSer sets virt
boundary as 4K - 1.
However, things will change after multipage bvec is introduced.
Thanks,
Ming
next prev parent reply other threads:[~2018-11-05 12:02 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-05 10:23 [PATCH] block: respect virtual boundary mask in bvecs Johannes Thumshirn
2018-11-05 10:55 ` Ming Lei
2018-11-05 11:50 ` Johannes Thumshirn
2018-11-05 12:01 ` Ming Lei [this message]
2018-11-06 12:34 ` Johannes Thumshirn
2018-11-06 14:56 ` Ming Lei
2018-11-06 15:14 ` Keith Busch
2018-11-07 3:14 ` Sagi Grimberg
2018-11-07 3:11 ` Sagi Grimberg
2018-11-06 14:31 ` Keith Busch
2018-11-06 14:53 ` Bart Van Assche
2018-11-06 14:56 ` Johannes Thumshirn
2018-11-07 3:30 ` Sagi Grimberg
2018-11-07 16:10 ` Bart Van Assche
2018-11-08 15:04 ` Christoph Hellwig
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