linux-kernel - Re: [RESEND PATCH] fs/pipe: Introduce a check to skip sleeping processes during pipe read/write

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <am7mlhd67ymicifo6qi56pw4e34cj3623drir3rvtisezpl4eu@e5zpca7g5ayy>
Date: Wed, 25 Dec 2024 08:53:05 -0500
From: Kent Overstreet <kent.overstreet@...ux.dev>
To: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc: WangYuli <wangyuli@...ontech.com>, viro@...iv.linux.org.uk, 
	brauner@...nel.org, jack@...e.cz, linux-fsdevel@...r.kernel.org, 
	linux-kernel@...r.kernel.org, yushengjin@...ontech.com, zhangdandan@...ontech.com, 
	guanwentao@...ontech.com, zhanjun@...ontech.com, oliver.sang@...el.com, 
	ebiederm@...ssion.com, colin.king@...onical.com, josh@...htriplett.org, 
	penberg@...helsinki.fi, manfred@...orfullife.com, mingo@...e.hu, jes@....com, hch@....de, 
	aia21@...tab.net, arjan@...radead.org, jgarzik@...ox.com, 
	neukum@...hschaft.cup.uni-muenchen.de, oliver@...kum.name, dada1@...mosbay.com, axboe@...nel.dk, 
	axboe@...e.de, nickpiggin@...oo.com.au, dhowells@...hat.com, nathans@....com, 
	rolandd@...co.com, tytso@....edu, bunk@...sta.de, pbadari@...ibm.com, 
	ak@...ux.intel.com, ak@...e.de, davem@...emloft.net, jsipek@...sunysb.edu
Subject: Re: [RESEND PATCH] fs/pipe: Introduce a check to skip sleeping
 processes during pipe read/write

On Wed, Dec 25, 2024 at 03:30:05PM +0200, Andy Shevchenko wrote:
> Don't you think the Cc list is a bit overloaded?

Indeed, my mail server doesn't let me reply-all.

> On Wed, Dec 25, 2024 at 05:42:02PM +0800, WangYuli wrote:
> > +config PIPE_SKIP_SLEEPER
> > +	bool "Skip sleeping processes during pipe read/write"
> > +	default n
> 
> 'n' is the default 'default', no need to have this line.

Actually, I'd say to skip the kconfig option for this. Kconfig options
that affect the behaviour of core code increase our testing burden, and
are another variable to account for when chasing down bugs, and the
potential overhead looks negligable.

Also, did you look at adding this optimization to wake_up()? No-op
wakeups are very common, I think this has wider applicability.