From: Christoph Hellwig <hch@lst.de>
To: Johannes Thumshirn <Johannes.Thumshirn@wdc.com>
Cc: Christoph Hellwig <hch@lst.de>,
"axboe@kernel.dk" <axboe@kernel.dk>,
"hannes@cmpxchg.org" <hannes@cmpxchg.org>,
"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>
Subject: Re: [PATCH 2/4] block: cleanup the memory stall accounting in submit_bio
Date: Tue, 28 Apr 2020 16:21:52 +0200 [thread overview]
Message-ID: <20200428142152.GA5439@lst.de> (raw)
In-Reply-To: <SN4PR0401MB3598CF483E12950DE63C1B719BAC0@SN4PR0401MB3598.namprd04.prod.outlook.com>
On Tue, Apr 28, 2020 at 02:12:49PM +0000, Johannes Thumshirn wrote:
> On 28/04/2020 13:28, Christoph Hellwig wrote:
> > Instead of a convoluted chain just check for REQ_OP_READ directly,
> > and keep all the memory stall code together in a single unlikely
> > branch.
>
> Looks good, I just have one question, why the 'unlikely' annotation for
> the psi code?
>
> In the current code, the psi path is not "unlikely" (only
> REQ_OP_WRITE_SAME is). Is there any measurable benefit coming from the
> annotation?
Following the unlikely check in __bio_add_page that Johanness added
there with the original addition.
next prev parent reply other threads:[~2020-04-28 14:21 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-28 11:27 a few small bio related cleanups Christoph Hellwig
2020-04-28 11:27 ` [PATCH 1/4] block: improve the submit_bio and generic_make_request documentation Christoph Hellwig
2020-04-28 14:16 ` Johannes Thumshirn
2020-04-28 14:17 ` Keith Busch
2020-04-28 11:27 ` [PATCH 2/4] block: cleanup the memory stall accounting in submit_bio Christoph Hellwig
2020-04-28 14:12 ` Johannes Thumshirn
2020-04-28 14:21 ` Christoph Hellwig [this message]
2020-04-28 15:06 ` Johannes Weiner
2020-04-28 11:27 ` [PATCH 3/4] block: replace BIO_QUEUE_ENTERED with BIO_CGROUP_ACCT Christoph Hellwig
2020-04-28 14:23 ` Johannes Thumshirn
2020-04-28 14:24 ` Christoph Hellwig
2020-04-28 14:26 ` Johannes Thumshirn
2020-04-28 11:27 ` [PATCH 4/4] block: add a bio_queue_enter helper Christoph Hellwig
2020-04-28 14:55 ` Johannes Thumshirn
2020-04-29 15:33 ` a few small bio related cleanups Jens Axboe
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