From: Dou Liyang <douly.fnst@cn.fujitsu.com>
To: Thomas Gleixner <tglx@linutronix.de>,
LKML <linux-kernel@vger.kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>,
Sebastian Siewior <bigeasy@linutronix.de>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
"David S. Miller" <davem@davemloft.net>,
Fenghua Yu <fenghua.yu@intel.com>,
Herbert Xu <herbert@gondor.apana.org.au>,
Lai Jiangshan <jiangshanlai@gmail.com>,
Len Brown <lenb@kernel.org>,
Michael Ellerman <mpe@ellerman.id.au>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
Tejun Heo <tj@kernel.org>, Tony Luck <tony.luck@intel.com>,
Viresh Kumar <viresh.kumar@linaro.org>
Subject: Re: [patch 02/13] workqueue: Provide work_on_cpu_safe()
Date: Thu, 13 Apr 2017 19:11:32 +0800 [thread overview]
Message-ID: <bfc05a46-07b8-c062-e526-3cf98310900e@cn.fujitsu.com> (raw)
In-Reply-To: <20170412201042.262610721@linutronix.de>
At 04/13/2017 04:07 AM, Thomas Gleixner wrote:
> work_on_cpu() is not protected against CPU hotplug. For code which requires
> to be either executed on an online CPU or to fail if the CPU is not
> available the callsite would have to protect against CPU hotplug.
>
> Provide a function which does get/put_online_cpus() around the call to
> work_on_cpu() and fails the call with -ENODEV if the target CPU is not
> online.
>
> Preparatory patch to convert several racy task affinity manipulations.
>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> Cc: Tejun Heo <tj@kernel.org>
> Cc: Lai Jiangshan <jiangshanlai@gmail.com>
> ---
> include/linux/workqueue.h | 5 +++++
> kernel/workqueue.c | 23 +++++++++++++++++++++++
> 2 files changed, 28 insertions(+)
>
> --- a/include/linux/workqueue.h
> +++ b/include/linux/workqueue.h
> @@ -608,8 +608,13 @@ static inline long work_on_cpu(int cpu,
> {
> return fn(arg);
> }
> +static inline long work_on_cpu_safe(int cpu, long (*fn)(void *), void *arg)
> +{
> + return fn(arg);
> +}
> #else
> long work_on_cpu(int cpu, long (*fn)(void *), void *arg);
> +long work_on_cpu_safe(int cpu, long (*fn)(void *), void *arg);
> #endif /* CONFIG_SMP */
>
> #ifdef CONFIG_FREEZER
> --- a/kernel/workqueue.c
> +++ b/kernel/workqueue.c
> @@ -4735,6 +4735,29 @@ long work_on_cpu(int cpu, long (*fn)(voi
> return wfc.ret;
> }
> EXPORT_SYMBOL_GPL(work_on_cpu);
> +
> +/**
There is an extra '*' :)
Thanks,
Liyang
> + * work_on_cpu_safe - run a function in thread context on a particular cpu
> + * @cpu: the cpu to run on
> + * @fn: the function to run
> + * @arg: the function argument
> + *
> + * Disables CPU hotplug and calls work_on_cpu(). The caller must not hold
> + * any locks which would prevent @fn from completing.
> + *
> + * Return: The value @fn returns.
> + */
> +long work_on_cpu_safe(int cpu, long (*fn)(void *), void *arg)
> +{
> + long ret = -ENODEV;
> +
> + get_online_cpus();
> + if (cpu_online(cpu))
> + ret = work_on_cpu(cpu, fn, arg);
> + put_online_cpus();
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(work_on_cpu_safe);
> #endif /* CONFIG_SMP */
>
> #ifdef CONFIG_FREEZER
next prev parent reply other threads:[~2017-04-13 11:11 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-12 20:07 [patch 00/13] sched/treewide: Clean up various racy task affinity issues Thomas Gleixner
2017-04-12 20:07 ` [patch 01/13] ia64/topology: Remove cpus_allowed manipulation Thomas Gleixner
2017-04-15 14:15 ` [tip:sched/core] " tip-bot for Thomas Gleixner
2017-04-12 20:07 ` [patch 02/13] workqueue: Provide work_on_cpu_safe() Thomas Gleixner
2017-04-13 11:11 ` Dou Liyang [this message]
2017-04-13 21:28 ` Thomas Gleixner
2017-04-14 4:18 ` Tejun Heo
2017-04-14 8:54 ` Peter Zijlstra
2017-04-14 9:51 ` Thomas Gleixner
2017-04-14 9:56 ` Peter Zijlstra
2017-04-15 14:16 ` [tip:sched/core] " tip-bot for Thomas Gleixner
2017-04-12 20:07 ` [patch 03/13] ia64/salinfo: Replace racy task affinity logic Thomas Gleixner
2017-04-15 14:17 ` [tip:sched/core] " tip-bot for Thomas Gleixner
2017-04-12 20:07 ` [patch 04/13] ia64/sn/hwperf: " Thomas Gleixner
2017-04-12 20:53 ` [patch V 2 " Thomas Gleixner
2017-04-15 14:17 ` [tip:sched/core] " tip-bot for Thomas Gleixner
2017-04-12 20:07 ` [patch 05/13] powerpc/smp: Replace open coded " Thomas Gleixner
2017-04-13 5:47 ` Michael Ellerman
2017-04-15 14:18 ` [tip:sched/core] " tip-bot for Thomas Gleixner
2017-04-12 20:07 ` [patch 06/13] sparc/sysfs: Replace racy " Thomas Gleixner
2017-04-13 1:52 ` David Miller
2017-04-13 8:17 ` [patch V2 " Thomas Gleixner
2017-04-15 14:18 ` [tip:sched/core] " tip-bot for Thomas Gleixner
2017-04-12 20:07 ` [patch 07/13] ACPI/processor: Fix error handling in __acpi_processor_start() Thomas Gleixner
2017-04-15 14:19 ` [tip:sched/core] " tip-bot for Thomas Gleixner
2017-04-12 20:07 ` [patch 08/13] ACPI/processor: Replace racy task affinity logic Thomas Gleixner
2017-04-13 11:39 ` Peter Zijlstra
2017-04-13 12:01 ` Thomas Gleixner
2017-04-13 12:52 ` Peter Zijlstra
2017-04-15 14:19 ` [tip:sched/core] " tip-bot for Thomas Gleixner
2017-04-12 20:07 ` [patch 09/13] cpufreq/ia64: " Thomas Gleixner
2017-04-12 20:55 ` [patch V2 " Thomas Gleixner
2017-04-15 14:20 ` [tip:sched/core] " tip-bot for Thomas Gleixner
2017-04-13 2:42 ` [patch 09/13] " Viresh Kumar
2017-04-12 20:07 ` [patch 10/13] cpufreq/sh: " Thomas Gleixner
2017-04-13 2:46 ` Viresh Kumar
2017-04-15 14:20 ` [tip:sched/core] " tip-bot for Thomas Gleixner
2017-04-12 20:07 ` [patch 11/13] cpufreq/sparc-us3: " Thomas Gleixner
2017-04-13 2:48 ` Viresh Kumar
2017-04-15 14:21 ` [tip:sched/core] " tip-bot for Thomas Gleixner
2017-04-12 20:07 ` [patch 12/13] cpufreq/sparc-us2e: " Thomas Gleixner
2017-04-13 2:50 ` Viresh Kumar
2017-04-13 8:19 ` [patch V2 " Thomas Gleixner
2017-04-13 8:22 ` [patch V3 " Thomas Gleixner
2017-04-15 14:21 ` [tip:sched/core] " tip-bot for Thomas Gleixner
2017-04-13 14:50 ` [patch V2 12/13] " David Miller
2017-04-12 20:07 ` [patch 13/13] crypto: n2 - " Thomas Gleixner
2017-04-13 4:56 ` Herbert Xu
2017-04-13 8:20 ` [patch V2 " Thomas Gleixner
2017-04-13 14:51 ` David Miller
2017-04-15 14:22 ` [tip:sched/core] crypto: N2 " tip-bot for Thomas Gleixner
2017-04-13 9:02 ` [patch 00/13] sched/treewide: Clean up various racy task affinity issues Peter Zijlstra
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