From: Peter Zijlstra <peterz@infradead.org> To: Oleg Nesterov <oleg@redhat.com> Cc: Marc Zyngier <Marc.Zyngier@arm.com>, Yong Zhang <yong.zhang0@gmail.com>, Ingo Molnar <mingo@elte.hu>, Frank Rowand <frank.rowand@am.sony.com>, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [BUG] "sched: Remove rq->lock from the first half of ttwu()" locks up on ARM Date: Thu, 26 May 2011 18:09:08 +0200 [thread overview] Message-ID: <1306426148.2497.83.camel@laptop> (raw) In-Reply-To: <1306425584.2497.81.camel@laptop> On Thu, 2011-05-26 at 17:59 +0200, Peter Zijlstra wrote: > On Thu, 2011-05-26 at 17:45 +0200, Oleg Nesterov wrote: > > Stupid question. Can't we fix this problem if we do > > > > - if (p == current) > > + if (cpu == raw_smp_processor_id()) > > > > ? > > > > I forgot the rules... but iirc task_cpu(p) can't be changed under us? > > Easy enough to test.. brain gave out again,. hold on ;-) The below seems to run all-right so far, I'll let it run for a while. --- arch/x86/include/asm/system.h | 2 ++ kernel/sched.c | 3 ++- kernel/sched_debug.c | 7 +++++++ 3 files changed, 11 insertions(+), 1 deletions(-) diff --git a/arch/x86/include/asm/system.h b/arch/x86/include/asm/system.h index c2ff2a1..2c597e8 100644 --- a/arch/x86/include/asm/system.h +++ b/arch/x86/include/asm/system.h @@ -10,6 +10,8 @@ #include <linux/kernel.h> #include <linux/irqflags.h> +#define __ARCH_WANT_INTERRUPTS_ON_CTXSW + /* entries in ARCH_DLINFO: */ #if defined(CONFIG_IA32_EMULATION) || !defined(CONFIG_X86_64) # define AT_VECTOR_SIZE_ARCH 2 diff --git a/kernel/sched.c b/kernel/sched.c index 2d12893..f3627e5 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2636,7 +2636,8 @@ try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags) * to spin on ->on_cpu if p is current, since that would * deadlock. */ - if (p == current) { + if (cpu == smp_processor_id()) { + p->sched_contributes_to_load = 0; ttwu_queue(p, cpu); goto stat; } diff --git a/kernel/sched_debug.c b/kernel/sched_debug.c index a6710a1..f0ff1de 100644 --- a/kernel/sched_debug.c +++ b/kernel/sched_debug.c @@ -332,6 +332,13 @@ static int sched_debug_show(struct seq_file *m, void *v) (int)strcspn(init_utsname()->version, " "), init_utsname()->version); +#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW + SEQ_printf(m, "__ARCH_WANT_INTERRUPTS_ON_CTXSW\n"); +#endif +#ifdef __ARCH_WANT_UNLOCKED_CTXSW + SEQ_printf(m, "__ARCH_WANT_UNLOCKED_CTXSW\n"); +#endif + #define P(x) \ SEQ_printf(m, "%-40s: %Ld\n", #x, (long long)(x)) #define PN(x) \
WARNING: multiple messages have this Message-ID (diff)
From: peterz@infradead.org (Peter Zijlstra) To: linux-arm-kernel@lists.infradead.org Subject: [BUG] "sched: Remove rq->lock from the first half of ttwu()" locks up on ARM Date: Thu, 26 May 2011 18:09:08 +0200 [thread overview] Message-ID: <1306426148.2497.83.camel@laptop> (raw) In-Reply-To: <1306425584.2497.81.camel@laptop> On Thu, 2011-05-26 at 17:59 +0200, Peter Zijlstra wrote: > On Thu, 2011-05-26 at 17:45 +0200, Oleg Nesterov wrote: > > Stupid question. Can't we fix this problem if we do > > > > - if (p == current) > > + if (cpu == raw_smp_processor_id()) > > > > ? > > > > I forgot the rules... but iirc task_cpu(p) can't be changed under us? > > Easy enough to test.. brain gave out again,. hold on ;-) The below seems to run all-right so far, I'll let it run for a while. --- arch/x86/include/asm/system.h | 2 ++ kernel/sched.c | 3 ++- kernel/sched_debug.c | 7 +++++++ 3 files changed, 11 insertions(+), 1 deletions(-) diff --git a/arch/x86/include/asm/system.h b/arch/x86/include/asm/system.h index c2ff2a1..2c597e8 100644 --- a/arch/x86/include/asm/system.h +++ b/arch/x86/include/asm/system.h @@ -10,6 +10,8 @@ #include <linux/kernel.h> #include <linux/irqflags.h> +#define __ARCH_WANT_INTERRUPTS_ON_CTXSW + /* entries in ARCH_DLINFO: */ #if defined(CONFIG_IA32_EMULATION) || !defined(CONFIG_X86_64) # define AT_VECTOR_SIZE_ARCH 2 diff --git a/kernel/sched.c b/kernel/sched.c index 2d12893..f3627e5 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2636,7 +2636,8 @@ try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags) * to spin on ->on_cpu if p is current, since that would * deadlock. */ - if (p == current) { + if (cpu == smp_processor_id()) { + p->sched_contributes_to_load = 0; ttwu_queue(p, cpu); goto stat; } diff --git a/kernel/sched_debug.c b/kernel/sched_debug.c index a6710a1..f0ff1de 100644 --- a/kernel/sched_debug.c +++ b/kernel/sched_debug.c @@ -332,6 +332,13 @@ static int sched_debug_show(struct seq_file *m, void *v) (int)strcspn(init_utsname()->version, " "), init_utsname()->version); +#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW + SEQ_printf(m, "__ARCH_WANT_INTERRUPTS_ON_CTXSW\n"); +#endif +#ifdef __ARCH_WANT_UNLOCKED_CTXSW + SEQ_printf(m, "__ARCH_WANT_UNLOCKED_CTXSW\n"); +#endif + #define P(x) \ SEQ_printf(m, "%-40s: %Ld\n", #x, (long long)(x)) #define PN(x) \
next prev parent reply other threads:[~2011-05-26 16:05 UTC|newest] Thread overview: 102+ messages / expand[flat|nested] mbox.gz Atom feed top 2011-05-24 18:13 [BUG] "sched: Remove rq->lock from the first half of ttwu()" locks up on ARM Marc Zyngier 2011-05-24 18:13 ` Marc Zyngier 2011-05-24 21:32 ` Peter Zijlstra 2011-05-24 21:32 ` Peter Zijlstra 2011-05-24 21:39 ` Ingo Molnar 2011-05-24 21:39 ` Ingo Molnar 2011-05-25 12:23 ` Marc Zyngier 2011-05-25 12:23 ` Marc Zyngier 2011-05-25 17:08 ` Peter Zijlstra 2011-05-25 17:08 ` Peter Zijlstra 2011-05-25 21:15 ` Peter Zijlstra 2011-05-25 21:15 ` Peter Zijlstra 2011-05-26 7:29 ` Yong Zhang 2011-05-26 7:29 ` Yong Zhang 2011-05-26 10:32 ` Peter Zijlstra 2011-05-26 10:32 ` Peter Zijlstra 2011-05-26 11:02 ` Marc Zyngier 2011-05-26 11:02 ` Marc Zyngier 2011-05-26 11:32 ` Peter Zijlstra 2011-05-26 11:32 ` Peter Zijlstra 2011-05-26 12:21 ` Peter Zijlstra 2011-05-26 12:21 ` Peter Zijlstra 2011-05-26 12:26 ` Ingo Molnar 2011-05-26 12:26 ` Ingo Molnar 2011-05-26 12:31 ` Russell King - ARM Linux 2011-05-26 12:31 ` Russell King - ARM Linux 2011-05-26 12:37 ` Peter Zijlstra 2011-05-26 12:37 ` Peter Zijlstra 2011-05-26 12:50 ` Ingo Molnar 2011-05-26 12:50 ` Ingo Molnar 2011-05-26 13:36 ` Russell King - ARM Linux 2011-05-26 13:36 ` Russell King - ARM Linux 2011-05-26 14:45 ` Catalin Marinas 2011-05-26 14:45 ` Catalin Marinas 2011-05-27 12:06 ` Ingo Molnar 2011-05-27 12:06 ` Ingo Molnar 2011-05-27 17:55 ` Russell King - ARM Linux 2011-05-27 17:55 ` Russell King - ARM Linux 2011-05-27 19:41 ` Nicolas Pitre 2011-05-27 19:41 ` Nicolas Pitre 2011-05-27 20:52 ` Russell King - ARM Linux 2011-05-27 20:52 ` Russell King - ARM Linux 2011-05-28 13:13 ` Peter Zijlstra 2011-05-28 13:13 ` Peter Zijlstra 2011-05-31 11:08 ` Michal Simek 2011-05-31 11:08 ` Michal Simek 2011-05-31 13:22 ` Peter Zijlstra 2011-05-31 13:22 ` Peter Zijlstra 2011-05-31 13:37 ` Michal Simek 2011-05-31 13:37 ` Michal Simek 2011-05-31 13:52 ` Peter Zijlstra 2011-05-31 13:52 ` Peter Zijlstra 2011-05-31 14:08 ` Michal Simek 2011-05-31 14:08 ` Michal Simek 2011-05-31 14:29 ` Peter Zijlstra 2011-05-31 14:29 ` Peter Zijlstra 2011-05-29 10:21 ` Catalin Marinas 2011-05-29 10:21 ` Catalin Marinas 2011-05-29 10:26 ` Russell King - ARM Linux 2011-05-29 10:26 ` Russell King - ARM Linux 2011-05-29 12:01 ` Catalin Marinas 2011-05-29 12:01 ` Catalin Marinas 2011-05-29 13:19 ` Russell King - ARM Linux 2011-05-29 13:19 ` Russell King - ARM Linux 2011-05-29 21:21 ` Catalin Marinas 2011-05-29 21:21 ` Catalin Marinas 2011-05-29 9:51 ` Catalin Marinas 2011-05-29 9:51 ` Catalin Marinas 2011-06-06 10:29 ` Pavel Machek 2011-06-06 10:29 ` Pavel Machek 2011-05-26 14:56 ` Marc Zyngier 2011-05-26 14:56 ` Marc Zyngier 2011-05-26 15:45 ` Oleg Nesterov 2011-05-26 15:45 ` Oleg Nesterov 2011-05-26 15:59 ` Peter Zijlstra 2011-05-26 15:59 ` Peter Zijlstra 2011-05-26 16:09 ` Peter Zijlstra [this message] 2011-05-26 16:09 ` Peter Zijlstra 2011-05-26 16:20 ` Marc Zyngier 2011-05-26 16:20 ` Marc Zyngier 2011-05-26 16:32 ` Peter Zijlstra 2011-05-26 16:32 ` Peter Zijlstra 2011-05-27 8:01 ` Marc Zyngier 2011-05-27 8:01 ` Marc Zyngier 2011-05-26 16:22 ` Marc Zyngier 2011-05-26 16:22 ` Marc Zyngier 2011-05-26 17:04 ` Oleg Nesterov 2011-05-26 17:04 ` Oleg Nesterov 2011-05-26 17:17 ` Peter Zijlstra 2011-05-26 17:17 ` Peter Zijlstra 2011-05-26 17:23 ` Peter Zijlstra 2011-05-26 17:23 ` Peter Zijlstra 2011-05-26 17:49 ` Oleg Nesterov 2011-05-26 17:49 ` Oleg Nesterov 2011-05-27 7:01 ` Yong Zhang 2011-05-27 7:01 ` Yong Zhang 2011-05-27 15:23 ` Santosh Shilimkar 2011-05-27 15:23 ` Santosh Shilimkar 2011-05-27 15:29 ` Marc Zyngier 2011-05-27 15:29 ` Marc Zyngier 2011-05-27 15:30 ` Santosh Shilimkar 2011-05-27 15:30 ` Santosh Shilimkar
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