From: Frederic Weisbecker <fweisbec@gmail.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: mingo@kernel.org, linux-kernel@vger.kernel.org,
torvalds@linux-foundation.org, oleg@redhat.com,
umgwanakikbuti@gmail.com, tglx@linutronix.de,
rostedt@goodmis.org
Subject: Re: [PATCH v2 01/12] sched: Simplify INIT_PREEMPT_COUNT
Date: Thu, 1 Oct 2015 15:25:46 +0200 [thread overview]
Message-ID: <20151001132546.GF3432@lerouge> (raw)
In-Reply-To: <20150930072303.631400497@infradead.org>
On Wed, Sep 30, 2015 at 09:10:36AM +0200, Peter Zijlstra wrote:
> As per commit d86ee4809d03 ("sched: optimize cond_resched()") we need
> PREEMPT_ACTIVE to avoid cond_resched() from working before the
> scheduler is setup.
>
> However, keeping preemption disabled should do the same thing already,
> making the PREEMPT_ACTIVE part entirely redundant.
>
> The only complication is !PREEMPT_COUNT kernels, where
> PREEMPT_DISABLED ends up being 0. Instead we use an unconditional
> PREEMPT_OFFSET to set preempt_count() even on !PREEMPT_COUNT kernels.
>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Frederic Weisbecker <fweisbec@gmail.com>
next prev parent reply other threads:[~2015-10-01 13:25 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-30 7:10 [PATCH v2 00/12] sched: Killing PREEMPT_ACTIVE Peter Zijlstra
2015-09-30 7:10 ` [PATCH v2 01/12] sched: Simplify INIT_PREEMPT_COUNT Peter Zijlstra
2015-09-30 9:04 ` Steven Rostedt
2015-09-30 20:39 ` Thomas Gleixner
2015-10-01 13:25 ` Frederic Weisbecker [this message]
2015-09-30 7:10 ` [PATCH v2 02/12] sched: Rework TASK_DEAD preemption exception Peter Zijlstra
2015-09-30 7:10 ` [PATCH v2 03/12] sched: Create preempt_count invariant Peter Zijlstra
2015-09-30 9:32 ` Steven Rostedt
2015-09-30 11:13 ` Peter Zijlstra
2015-09-30 13:36 ` Steven Rostedt
2015-09-30 7:10 ` [PATCH v2 04/12] sched: Add preempt argument to __schedule() Peter Zijlstra
2015-09-30 7:10 ` [PATCH v2 05/12] sched: Fix trace_sched_switch() Peter Zijlstra
2015-09-30 7:10 ` [PATCH v2 06/12] sched: Stop setting PREEMPT_ACTIVE Peter Zijlstra
2015-10-01 15:27 ` Frederic Weisbecker
2015-09-30 7:10 ` [PATCH v2 07/12] sched: Robustify preemption leak checks Peter Zijlstra
2015-09-30 9:35 ` Steven Rostedt
2015-09-30 7:10 ` [PATCH v2 08/12] sched: Simplify preempt_count tests Peter Zijlstra
2015-10-01 15:31 ` Frederic Weisbecker
2015-09-30 7:10 ` [PATCH v2 09/12] sched, x86: Kill saved_preempt_count Peter Zijlstra
2015-10-01 15:40 ` Frederic Weisbecker
2015-09-30 7:10 ` [PATCH v2 10/12] sched: Kill PREEMPT_ACTIVE Peter Zijlstra
2015-10-01 15:41 ` Frederic Weisbecker
2015-09-30 7:10 ` [PATCH v2 11/12] sched: More notrace Peter Zijlstra
2015-09-30 7:10 ` [PATCH v2 12/12] sched: Add preempt_count invariant check Peter Zijlstra
2015-09-30 9:38 ` Steven Rostedt
2015-09-30 11:15 ` Peter Zijlstra
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