From: "jianchao.wang" <jianchao.w.wang@oracle.com>
To: Jens Axboe <axboe@kernel.dk>
Cc: ming.lei@redhat.com, linux-block@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH V5 1/6] blk-mq: make __blk_mq_issue_directly be able to accept NULL cookie pointer
Date: Tue, 13 Nov 2018 10:41:40 +0800 [thread overview]
Message-ID: <87aa2951-54ce-e979-790f-8f1c18d78f14@oracle.com> (raw)
In-Reply-To: <01bd2f70-cc78-9bfd-aa30-b73c44eaa9bb@kernel.dk>
Hi Jens
On 11/13/18 1:10 AM, Jens Axboe wrote:
> On 11/12/18 2:23 AM, Jianchao Wang wrote:
>> Make __blk_mq_issue_directly be able to accept a NULL cookie pointer
>> and remove the dummy unused_cookie in blk_mq_request_issue_directly.
>
> What's the reasoning behind this? Seems faster to store the cookie
> always, instead of introducing a branch to the hot path.
>
It is to make the interface more usable then we needn't input a dummy cookie
pointer but just a NULL if we don't use the return cookie.
If the introduced branch in hot path is concerned, I could drop this one.
Thanks
Jianchao
next prev parent reply other threads:[~2018-11-13 2:41 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-12 9:23 [PATCH V5 0/6] blk-mq: refactor and fix on issue request directly Jianchao Wang
2018-11-12 9:23 ` [PATCH V5 1/6] blk-mq: make __blk_mq_issue_directly be able to accept NULL cookie pointer Jianchao Wang
2018-11-12 17:10 ` Jens Axboe
2018-11-13 2:41 ` jianchao.wang [this message]
2018-11-12 9:23 ` [PATCH V5 2/6] blk-mq: refactor the code of issue request directly Jianchao Wang
2018-11-13 3:22 ` Jens Axboe
2018-11-13 4:12 ` jianchao.wang
2018-11-12 9:23 ` [PATCH V5 3/6] blk-mq: fix issue directly case when q is stopped or quiesced Jianchao Wang
2018-11-12 9:23 ` [PATCH V5 4/6] blk-mq: ensure hctx to be ran on mapped cpu when issue directly Jianchao Wang
2018-11-12 9:23 ` [PATCH V5 5/6] blk-mq: issue directly with bypass 'false' in blk_mq_sched_insert_requests Jianchao Wang
2018-11-12 9:23 ` [PATCH V5 6/6] blk-mq: replace and kill blk_mq_request_issue_directly Jianchao Wang
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