From: Oleg Nesterov <oleg@redhat.com>
To: Kirill Tkhai <ktkhai@parallels.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
Kirill Tkhai <tkhai@yandex.ru>,
linux-kernel@vger.kernel.org, nicolas.pitre@linaro.org,
pjt@google.com, rostedt@goodmis.org, umgwanakikbuti@gmail.com,
tim.c.chen@linux.intel.com, mingo@kernel.org
Subject: Re: [PATCH v2 2/5] sched: Teach scheduler to understand ONRQ_MIGRATING state
Date: Tue, 29 Jul 2014 18:19:28 +0200 [thread overview]
Message-ID: <20140729161928.GA31298@redhat.com> (raw)
In-Reply-To: <1406627582.3600.9.camel@tkhai>
On 07/29, Kirill Tkhai wrote:
>
> How about this? Everything is inside task_rq_lock() now. The patch
> became much less.
And with this change task_migrating() is not possible under
task_rq_lock() or __task_rq_lock(). This means that 1/5 can be simplified
too.
__migrate_swap_task() is probably the notable exception...
Off-topic, but it takes 2 ->pi_lock's. This means it can deadlock with
try_to_wake_up_local() (if a 3rd process does ttwu() and waits for
->on_cpu == 0). But I guess __migrate_swap_task() should not play with
PF_WQ_WORKER threads.
Oleg.
next prev parent reply other threads:[~2014-07-29 16:22 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-26 14:58 [PATCH v2 0/5] sched: Add on_rq states and remove several double rq locks Kirill Tkhai
2014-07-26 14:59 ` [PATCH v2 1/5] sched: Wrapper for checking task_struct's .on_rq Kirill Tkhai
2014-07-26 14:59 ` [PATCH v2 2/5] sched: Teach scheduler to understand ONRQ_MIGRATING state Kirill Tkhai
2014-07-28 8:01 ` Peter Zijlstra
2014-07-28 9:05 ` Kirill Tkhai
2014-07-29 9:53 ` Kirill Tkhai
2014-07-29 12:38 ` Peter Zijlstra
2014-07-29 16:19 ` Oleg Nesterov [this message]
2014-07-30 8:04 ` Kirill Tkhai
2014-07-30 14:41 ` Oleg Nesterov
2014-07-30 21:25 ` Kirill Tkhai
2014-07-26 14:59 ` [PATCH v2 3/5] sched: Remove double_rq_lock() from __migrate_task() Kirill Tkhai
2014-07-26 14:59 ` [PATCH v2 4/5] sched/fair: Remove double_lock_balance() from active_load_balance_cpu_stop() Kirill Tkhai
2014-07-26 14:59 ` [PATCH v2 5/5] sched/fair: Remove double_lock_balance() from load_balance() Kirill Tkhai
2014-07-29 12:57 ` Peter Zijlstra
2014-07-26 19:39 ` [PATCH v2 0/5] sched: Add on_rq states and remove several double rq locks Oleg Nesterov
2014-07-27 21:26 ` Kirill Tkhai
2014-07-28 13:19 ` Oleg Nesterov
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