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From: Christoph Hellwig <hch@infradead.org>
To: Guoqing Jiang <jgq516@gmail.com>
Cc: song@kernel.org, linux-raid@vger.kernel.org, artur.paszkiewicz@intel.com
Subject: Re: [PATCH V2 2/7] md: add accounting_bio for raid0 and raid5
Date: Mon, 24 May 2021 09:45:28 +0100	[thread overview]
Message-ID: <YKtnqNRcJV2xj/Mf@infradead.org> (raw)
In-Reply-To: <20210521005521.713106-3-jiangguoqing@kylinos.cn>

On Fri, May 21, 2021 at 08:55:16AM +0800, Guoqing Jiang wrote:
> Let's introduce accounting_bio which checks if md needs clone the bio
> for accounting.
> 
> And add relevant function to raid0 and raid5 given both don't have
> their own clone infrastrure, also checks if it is split bio.

Please don't add another indirect call in the I/O submission fast path.
With Spectre mitigations these are really slow, and also are hard to
follow.

I think moving the call to allocate the accounting bio clone entirely
into the personalities is probably the cleanest approach without any
of these downsides.

  parent reply	other threads:[~2021-05-24  8:46 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-21  0:55 [PATCH V2 0/7] md: io stats accounting Guoqing Jiang
2021-05-21  0:55 ` [PATCH V2 1/7] md: revert " Guoqing Jiang
2021-05-21  0:55 ` [PATCH V2 2/7] md: add accounting_bio for raid0 and raid5 Guoqing Jiang
2021-05-24  5:48   ` Song Liu
2021-05-24  8:45   ` Christoph Hellwig [this message]
2021-05-21  0:55 ` [PATCH V2 3/7] md: the latest try for improve io stats accounting Guoqing Jiang
2021-05-21  7:32   ` Artur Paszkiewicz
2021-05-21  7:43     ` Guoqing Jiang
2021-05-21  0:55 ` [PATCH V2 4/7] md/raid1: rename print_msg with r1bio_existed Guoqing Jiang
2021-05-21  0:55 ` [PATCH V2 5/7] md/raid1: enable io accounting Guoqing Jiang
2021-05-21  0:55 ` [PATCH V2 6/7] md/raid10: " Guoqing Jiang
2021-05-21  0:55 ` [PATCH V2 7/7] md: mark some personalities as deprecated Guoqing Jiang
2021-05-21  8:00 ` [UPDATE PATCH V2 3/7] md: the latest try for improve io stats accounting Guoqing Jiang
2021-05-24  5:49   ` Song Liu
2021-05-24  6:04 ` [PATCH V2 0/7] md: " Song Liu
2021-05-27 14:09   ` Paweł Wiejacha

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