linux-kernel - Re: [PATCH 3/7] sched: Update rq clock on tickless CPUs before calling check_preempt

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: <1365513508.30071.4.camel@laptop>
Date:	Tue, 09 Apr 2013 15:18:28 +0200
From:	Peter Zijlstra <peterz@...radead.org>
To:	Frederic Weisbecker <fweisbec@...il.com>
Cc:	Ingo Molnar <mingo@...nel.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Alessio Igor Bogani <abogani@...nel.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Chris Metcalf <cmetcalf@...era.com>,
	Christoph Lameter <cl@...ux.com>,
	Geoff Levand <geoff@...radead.org>,
	Gilad Ben Yossef <gilad@...yossef.com>,
	Hakan Akkan <hakanakkan@...il.com>,
	Li Zhong <zhong@...ux.vnet.ibm.com>,
	Namhyung Kim <namhyung.kim@....com>,
	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
	Paul Gortmaker <paul.gortmaker@...driver.com>,
	Steven Rostedt <rostedt@...dmis.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Paul Turner <pjt@...gle.com>, Mike Galbraith <efault@....de>
Subject: Re: [PATCH 3/7] sched: Update rq clock on tickless CPUs before
 calling check_preempt_curr()

On Sat, 2013-04-06 at 18:45 +0200, Frederic Weisbecker wrote:
> check_preempt_wakeup() of fair class needs an uptodate sched clock
> value to update runtime stats of the current task.
> 
> When a task is woken up, activate_task() is usually called right
> before
> ttwu_do_wakeup() unless the task is still in the runqueue. In this
> case we need to update the rq clock manually in case the CPU runs
> tickless because ttwu_do_wakeup() calls check_preempt_wakeup().

again, same story.. I think the entire nohz specific clock update stuff
is completely broken and you're finding sites that are simply missing
clock updates.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/