From: Peter Zijlstra <peterz@infradead.org>
To: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH 3/4] sched: Pull preemption disablement to __schedule() caller
Date: Wed, 28 Jan 2015 16:50:44 +0100 [thread overview]
Message-ID: <20150128155044.GJ23038@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <1422404652-29067-4-git-send-email-fweisbec@gmail.com>
On Wed, Jan 28, 2015 at 01:24:11AM +0100, Frederic Weisbecker wrote:
> +++ b/kernel/sched/core.c
> @@ -2760,7 +2760,6 @@ static void __sched __schedule(void)
> struct rq *rq;
> int cpu;
>
> - preempt_disable();
Implies barrier();
> cpu = smp_processor_id();
> rq = cpu_rq(cpu);
> rcu_note_context_switch();
> @@ -2822,8 +2821,6 @@ static void __sched __schedule(void)
> raw_spin_unlock_irq(&rq->lock);
>
> post_schedule(rq);
implies barrier();
> -
> - sched_preempt_enable_no_resched();
> }
>
> static inline void sched_submit_work(struct task_struct *tsk)
> @@ -2883,9 +2882,9 @@ void __sched schedule_preempt_disabled(void)
> static void preempt_schedule_common(void)
> {
> do {
> - preempt_count_add(PREEMPT_ACTIVE);
> + preempt_count_add(PREEMPT_ACTIVE + PREEMPT_CHECK_OFFSET);
Does _NOT_ imply barrier();
> __schedule();
> - preempt_count_sub(PREEMPT_ACTIVE);
idem.
> + preempt_count_sub(PREEMPT_ACTIVE + PREEMPT_CHECK_OFFSET);
>
> /*
> * Check again in case we missed a preemption opportunity
next prev parent reply other threads:[~2015-01-29 1:41 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-28 0:24 [PATCH 0/4] sched: schedule/preempt optimizations and cleanups Frederic Weisbecker
2015-01-28 0:24 ` [PATCH 1/4] sched: Pull resched loop to __schedule() callers Frederic Weisbecker
2015-02-04 14:36 ` [tip:sched/core] " tip-bot for Frederic Weisbecker
2015-01-28 0:24 ` [RFC PATCH 2/4] sched: Use traced preempt count operations to toggle PREEMPT_ACTIVE Frederic Weisbecker
2015-01-28 1:42 ` Steven Rostedt
2015-01-28 13:59 ` Frederic Weisbecker
2015-01-28 15:04 ` Steven Rostedt
2015-01-28 15:42 ` Peter Zijlstra
2015-02-02 17:22 ` Frederic Weisbecker
2015-01-28 0:24 ` [PATCH 3/4] sched: Pull preemption disablement to __schedule() caller Frederic Weisbecker
2015-01-28 15:50 ` Peter Zijlstra [this message]
2015-02-02 17:53 ` Frederic Weisbecker
2015-02-03 10:53 ` Peter Zijlstra
2015-02-04 17:31 ` Frederic Weisbecker
2015-02-04 17:48 ` Peter Zijlstra
2015-01-28 0:24 ` [RFC PATCH 4/4] sched: Account PREEMPT_ACTIVE context as atomic Frederic Weisbecker
2015-01-28 15:46 ` Peter Zijlstra
2015-02-02 17:29 ` Frederic Weisbecker
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