From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753130AbZCFLlm (ORCPT ); Fri, 6 Mar 2009 06:41:42 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751401AbZCFLld (ORCPT ); Fri, 6 Mar 2009 06:41:33 -0500 Received: from cn.fujitsu.com ([222.73.24.84]:57620 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1750849AbZCFLld (ORCPT ); Fri, 6 Mar 2009 06:41:33 -0500 Message-ID: <49B10BA4.9070209@cn.fujitsu.com> Date: Fri, 06 Mar 2009 19:40:20 +0800 From: Lai Jiangshan User-Agent: Thunderbird 2.0.0.6 (Windows/20070728) MIME-Version: 1.0 To: Ingo Molnar CC: LKML , Peter Zijlstra Subject: [PATCH -tip] sched: cleanup for TIF_NEED_RESCHED References: <49B0F9C2.8060200@cn.fujitsu.com> <20090306104925.GA21168@elte.hu> In-Reply-To: <20090306104925.GA21168@elte.hu> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Ingo Molnar wrote: > * Lai Jiangshan wrote: > >> Impact: cleanup >> >> use need_resched() instead of unlikely(test_thread_flag(TIF_NEED_RESCHED)) >> >> Signed-off-by: Lai Jiangshan > > looks good - but it does not apply cleanly to the latest > scheduler tree: > > http://people.redhat.com/mingo/tip.git/README > > Could you please send a merged up patch and also make sure > there's no other TIF_NEED_RESCHED usage in kernel/sched.c that > could be converted to need_resched()? > > Thanks, > > Ingo > > From: Lai Jiangshan Impact: cleanup Use test_tsk_need_resched(), set_tsk_need_resched(), need_resched() instead of using TIF_NEED_RESCHED. Signed-off-by: Lai Jiangshan --- diff --git a/kernel/sched.c b/kernel/sched.c index 63e8414..81b7c8b 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -1210,10 +1210,10 @@ static void resched_task(struct task_struct *p) assert_spin_locked(&task_rq(p)->lock); - if (unlikely(test_tsk_thread_flag(p, TIF_NEED_RESCHED))) + if (test_tsk_need_resched(p)) return; - set_tsk_thread_flag(p, TIF_NEED_RESCHED); + set_tsk_need_resched(p); cpu = task_cpu(p); if (cpu == smp_processor_id()) @@ -1269,7 +1269,7 @@ void wake_up_idle_cpu(int cpu) * lockless. The worst case is that the other CPU runs the * idle task through an additional NOOP schedule() */ - set_tsk_thread_flag(rq->idle, TIF_NEED_RESCHED); + set_tsk_need_resched(rq->idle); /* NEED_RESCHED must be visible before we test polling */ smp_mb(); @@ -4795,12 +4795,11 @@ need_resched_nonpreemptible: asmlinkage void __sched schedule(void) { -need_resched: - preempt_disable(); - __schedule(); - preempt_enable_no_resched(); - if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) - goto need_resched; + do { + preempt_disable(); + __schedule(); + preempt_enable_no_resched(); + } while (need_resched()); } EXPORT_SYMBOL(schedule); @@ -4892,7 +4891,7 @@ asmlinkage void __sched preempt_schedule(void) * between schedule and now. */ barrier(); - } while (unlikely(test_thread_flag(TIF_NEED_RESCHED))); + } while (need_resched()); } EXPORT_SYMBOL(preempt_schedule); @@ -4921,7 +4920,7 @@ asmlinkage void __sched preempt_schedule_irq(void) * between schedule and now. */ barrier(); - } while (unlikely(test_thread_flag(TIF_NEED_RESCHED))); + } while (need_resched()); } #endif /* CONFIG_PREEMPT */ diff --git a/lib/kernel_lock.c b/lib/kernel_lock.c index 01a3c22..39f1029 100644 --- a/lib/kernel_lock.c +++ b/lib/kernel_lock.c @@ -39,7 +39,7 @@ static __cacheline_aligned_in_smp DEFINE_SPINLOCK(kernel_flag); int __lockfunc __reacquire_kernel_lock(void) { while (!_raw_spin_trylock(&kernel_flag)) { - if (test_thread_flag(TIF_NEED_RESCHED)) + if (need_resched()) return -EAGAIN; cpu_relax(); }