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From: CGEL <cgel.zte@gmail.com>
To: Johannes Weiner <hannes@cmpxchg.org>
Cc: axboe@kernel.dk, viro@zeniv.linux.org.uk,
	linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-fsdevel@vger.kernel.org, akpm@linux-foundation.org,
	Yang Yang <yang.yang29@zte.com.cn>,
	Ran Xiaokai <ran.xiaokai@zte.com.cn>
Subject: Re: [PATCH] block/psi: make PSI annotations of submit_bio only work for file pages
Date: Tue, 22 Mar 2022 03:44:28 +0000	[thread overview]
Message-ID: <6239461f.1c69fb81.df45.a622@mx.google.com> (raw)
In-Reply-To: <YjiMsGoXoDU+FwsS@cmpxchg.org>

On Mon, Mar 21, 2022 at 10:33:20AM -0400, Johannes Weiner wrote:
> On Wed, Mar 16, 2022 at 06:39:28AM +0000, cgel.zte@gmail.com wrote:
> > From: Yang Yang <yang.yang29@zte.com.cn>
> > 
> > psi tracks the time spent on submitting the IO of refaulting file pages
> > and anonymous pages[1]. But after we tracks refaulting anonymous pages
> > in swap_readpage[2][3], there is no need to track refaulting anonymous
> > pages in submit_bio.
> > 
> > So this patch can reduce redundant calling of psi_memstall_enter. And
> > make it easier to track refaulting file pages and anonymous pages
> > separately.
> 
> I don't think this is an improvement.
> 
> psi_memstall_enter() will check current->in_memstall once, detect the
> nested call, and bail. Your patch checks PageSwapBacked for every page
> being added. It's more branches for less robust code.

And PageSwapBacked checking is after unlikely(PageWorkingset(page), so I think
the impact is little.

      parent reply	other threads:[~2022-03-22  3:44 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-16  6:39 [PATCH] block/psi: make PSI annotations of submit_bio only work for file pages cgel.zte
2022-03-16  8:48 ` Christoph Hellwig
2022-03-17  2:18   ` CGEL
2022-03-21 14:33 ` Johannes Weiner
2022-03-22  2:47   ` CGEL
2022-03-22 13:27     ` Johannes Weiner
2022-03-23  6:10       ` CGEL
     [not found]       ` <20220323061058.GA2343452@cgel.zte@gmail.com>
2022-03-30  8:34         ` CGEL
2022-03-30 13:00           ` Johannes Weiner
2022-03-30 13:04             ` Christoph Hellwig
2022-03-30 13:49               ` Jens Axboe
2022-03-30 15:45               ` Johannes Weiner
2022-03-30 15:54                 ` Christoph Hellwig
2022-03-30 16:17                   ` Johannes Weiner
2022-03-31  5:15                     ` Christoph Hellwig
2022-03-31 19:07                       ` Johannes Weiner
2022-03-31  2:21             ` CGEL
2022-03-22  3:44   ` CGEL [this message]

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