From: Matt Fleming <matt@codeblueprint.co.uk>
To: Wanpeng Li <kernellwp@gmail.com>
Cc: linux-kernel@vger.kernel.org, Wanpeng Li <wanpeng.li@hotmail.com>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@kernel.org>
Subject: Re: [PATCH] sched/fair: Update rq clock before changing a task's CPU affinity
Date: Wed, 22 Feb 2017 09:33:32 +0000 [thread overview]
Message-ID: <20170222093332.GS28416@codeblueprint.co.uk> (raw)
In-Reply-To: <1487749975-5994-1-git-send-email-wanpeng.li@hotmail.com>
On Tue, 21 Feb, at 11:52:55PM, Wanpeng Li wrote:
> From: Wanpeng Li <wanpeng.li@hotmail.com>
>
> ------------[ cut here ]------------
> WARNING: CPU: 6 PID: 81 at kernel/sched/sched.h:812 set_next_entity+0x11d/0x380
> rq->clock_update_flags < RQCF_ACT_SKIP
> CPU: 6 PID: 81 Comm: torture_shuffle Not tainted 4.10.0+ #1
> Hardware name: LENOVO ThinkCentre M8500t-N000/SHARKBAY, BIOS FBKTC1AUS 02/16/2016
> Call Trace:
> dump_stack+0x85/0xc2
> __warn+0xcb/0xf0
> warn_slowpath_fmt+0x5f/0x80
> set_next_entity+0x11d/0x380
> set_curr_task_fair+0x2b/0x60
> do_set_cpus_allowed+0x139/0x180
> __set_cpus_allowed_ptr+0x113/0x260
> set_cpus_allowed_ptr+0x10/0x20
> torture_shuffle+0xfd/0x180
> kthread+0x10f/0x150
> ? torture_shutdown_init+0x60/0x60
> ? kthread_create_on_node+0x60/0x60
> ret_from_fork+0x31/0x40
> ---[ end trace dd94d92344cea9c6 ]---
>
> This is triggered during boot when CONFIG_SCHED_DEBUG is enabled. The
> task is running && !queued, so there is no rq clock update before calling
> set_curr_task.
>
> This patch fixes it by updating rq clock after holding rq->lock/pi_lock
> just as what other dequeue + put_prev + enqueue + set_curr story does.
>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Ingo Molnar <mingo@kernel.org>
> Cc: Matt Fleming <matt@codeblueprint.co.uk>
> Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
> ---
> kernel/sched/core.c | 1 +
> 1 file changed, 1 insertion(+)
This looks correct. Thanks for doing it.
Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>
next prev parent reply other threads:[~2017-02-22 9:33 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-22 7:52 [PATCH] sched/fair: Update rq clock before changing a task's CPU affinity Wanpeng Li
2017-02-22 9:33 ` Matt Fleming [this message]
2017-02-24 9:16 ` [tip:sched/urgent] " tip-bot for Wanpeng Li
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