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: <20240527080503.GU22557@noisy.programming.kicks-ass.net>
Date: Mon, 27 May 2024 10:05:03 +0200
From: Peter Zijlstra <peterz@...radead.org>
To: Mike Galbraith <efault@....de>, kprateek.nayak@....com
Cc: Chunxin Zang <spring.cxz@...il.com>, mingo@...hat.com,
	juri.lelli@...hat.com, vincent.guittot@...aro.org,
	dietmar.eggemann@....com, rostedt@...dmis.org, bsegall@...gle.com,
	mgorman@...e.de, bristot@...hat.com, vschneid@...hat.com,
	linux-kernel@...r.kernel.org, yu.c.chen@...el.com,
	yangchen11@...iang.com, zhouchunhua@...iang.com,
	zangchunxin@...iang.com
Subject: Re: [PATCH] sched/fair: Reschedule the cfs_rq when current is
 ineligible

On Sat, May 25, 2024 at 08:41:28AM +0200, Mike Galbraith wrote:

> -	if (pick_eevdf(cfs_rq) == pse)
> -		goto preempt;
> -
> -	return;
> +	if (pick_eevdf(cfs_rq) == se)
> +		return;

Right, this will preempt more.

This is probably going to make Prateek's case worse though. Then again,
I was already leaning to towards not making his stronger slice
protection default, because it simply hurts too much elsewhere.

Still, his observation that placing tasks can move V left which in turn
can cause the just scheduled in current non-eligible and cause
over-scheduling is valid -- just not sure what to do about it yet.

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ