From: Petr Mladek <pmladek@suse.com> To: Andrew Morton <akpm@linux-foundation.org>, Oleg Nesterov <oleg@redhat.com>, Tejun Heo <tj@kernel.org>, Ingo Molnar <mingo@redhat.com>, Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org>, "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>, Josh Triplett <josh@joshtriplett.org>, Thomas Gleixner <tglx@linutronix.de>, Linus Torvalds <torvalds@linux-foundation.org>, Jiri Kosina <jkosina@suse.cz>, Borislav Petkov <bp@suse.de>, Michal Hocko <mhocko@suse.cz>, linux-mm@kvack.org, Vlastimil Babka <vbabka@suse.cz>, linux-api@vger.kernel.org, linux-kernel@vger.kernel.org, Petr Mladek <pmladek@suse.com> Subject: [PATCH v4 02/22] kthread/smpboot: Do not park in kthread_create_on_cpu() Date: Mon, 25 Jan 2016 16:44:51 +0100 [thread overview] Message-ID: <1453736711-6703-3-git-send-email-pmladek@suse.com> (raw) In-Reply-To: <1453736711-6703-1-git-send-email-pmladek@suse.com> kthread_create_on_cpu() was added by the commit 2a1d446019f9a5983e ("kthread: Implement park/unpark facility"). It is currently used only when enabling new CPU. For this purpose, the newly created kthread has to be parked. The CPU binding is a bit tricky. The kthread is parked when the CPU has not been allowed yet. And the CPU is bound when the kthread is unparked. The function would be useful for more per-CPU kthreads, e.g. bnx2fc_thread, fcoethread. For this purpose, the newly created kthread should stay in the uninterruptible state. This patch moves the parking into smpboot. It binds the thread already when created. Then the function might be used universally. Also the behavior is consistent with kthread_create() and kthread_create_on_node(). Signed-off-by: Petr Mladek <pmladek@suse.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> --- kernel/kthread.c | 8 ++++++-- kernel/smpboot.c | 5 +++++ 2 files changed, 11 insertions(+), 2 deletions(-) diff --git a/kernel/kthread.c b/kernel/kthread.c index 9ff173dca1ae..1ffc11ec5546 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -390,10 +390,10 @@ struct task_struct *kthread_create_on_cpu(int (*threadfn)(void *data), cpu); if (IS_ERR(p)) return p; + kthread_bind(p, cpu); + /* CPU hotplug need to bind once again when unparking the thread. */ set_bit(KTHREAD_IS_PER_CPU, &to_kthread(p)->flags); to_kthread(p)->cpu = cpu; - /* Park the thread to get it out of TASK_UNINTERRUPTIBLE state */ - kthread_park(p); return p; } @@ -407,6 +407,10 @@ static void __kthread_unpark(struct task_struct *k, struct kthread *kthread) * which might be about to be cleared. */ if (test_and_clear_bit(KTHREAD_IS_PARKED, &kthread->flags)) { + /* + * Newly created kthread was parked when the CPU was offline. + * The binding was lost and we need to set it again. + */ if (test_bit(KTHREAD_IS_PER_CPU, &kthread->flags)) __kthread_bind(k, kthread->cpu, TASK_PARKED); wake_up_state(k, TASK_PARKED); diff --git a/kernel/smpboot.c b/kernel/smpboot.c index d264f59bff56..79f07014be6e 100644 --- a/kernel/smpboot.c +++ b/kernel/smpboot.c @@ -186,6 +186,11 @@ __smpboot_create_thread(struct smp_hotplug_thread *ht, unsigned int cpu) kfree(td); return PTR_ERR(tsk); } + /* + * Park the thread so that it could start right on the CPU + * when it is available. + */ + kthread_park(tsk); get_task_struct(tsk); *per_cpu_ptr(ht->store, cpu) = tsk; if (ht->create) { -- 1.8.5.6
WARNING: multiple messages have this Message-ID (diff)
From: Petr Mladek <pmladek@suse.com> To: Andrew Morton <akpm@linux-foundation.org>, Oleg Nesterov <oleg@redhat.com>, Tejun Heo <tj@kernel.org>, Ingo Molnar <mingo@redhat.com>, Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org>, "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>, Josh Triplett <josh@joshtriplett.org>, Thomas Gleixner <tglx@linutronix.de>, Linus Torvalds <torvalds@linux-foundation.org>, Jiri Kosina <jkosina@suse.cz>, Borislav Petkov <bp@suse.de>, Michal Hocko <mhocko@suse.cz>, linux-mm@kvack.org, Vlastimil Babka <vbabka@suse.cz>, linux-api@vger.kernel.org, linux-kernel@vger.kernel.org, Petr Mladek <pmladek@suse.com> Subject: [PATCH v4 02/22] kthread/smpboot: Do not park in kthread_create_on_cpu() Date: Mon, 25 Jan 2016 16:44:51 +0100 [thread overview] Message-ID: <1453736711-6703-3-git-send-email-pmladek@suse.com> (raw) In-Reply-To: <1453736711-6703-1-git-send-email-pmladek@suse.com> kthread_create_on_cpu() was added by the commit 2a1d446019f9a5983e ("kthread: Implement park/unpark facility"). It is currently used only when enabling new CPU. For this purpose, the newly created kthread has to be parked. The CPU binding is a bit tricky. The kthread is parked when the CPU has not been allowed yet. And the CPU is bound when the kthread is unparked. The function would be useful for more per-CPU kthreads, e.g. bnx2fc_thread, fcoethread. For this purpose, the newly created kthread should stay in the uninterruptible state. This patch moves the parking into smpboot. It binds the thread already when created. Then the function might be used universally. Also the behavior is consistent with kthread_create() and kthread_create_on_node(). Signed-off-by: Petr Mladek <pmladek@suse.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> --- kernel/kthread.c | 8 ++++++-- kernel/smpboot.c | 5 +++++ 2 files changed, 11 insertions(+), 2 deletions(-) diff --git a/kernel/kthread.c b/kernel/kthread.c index 9ff173dca1ae..1ffc11ec5546 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -390,10 +390,10 @@ struct task_struct *kthread_create_on_cpu(int (*threadfn)(void *data), cpu); if (IS_ERR(p)) return p; + kthread_bind(p, cpu); + /* CPU hotplug need to bind once again when unparking the thread. */ set_bit(KTHREAD_IS_PER_CPU, &to_kthread(p)->flags); to_kthread(p)->cpu = cpu; - /* Park the thread to get it out of TASK_UNINTERRUPTIBLE state */ - kthread_park(p); return p; } @@ -407,6 +407,10 @@ static void __kthread_unpark(struct task_struct *k, struct kthread *kthread) * which might be about to be cleared. */ if (test_and_clear_bit(KTHREAD_IS_PARKED, &kthread->flags)) { + /* + * Newly created kthread was parked when the CPU was offline. + * The binding was lost and we need to set it again. + */ if (test_bit(KTHREAD_IS_PER_CPU, &kthread->flags)) __kthread_bind(k, kthread->cpu, TASK_PARKED); wake_up_state(k, TASK_PARKED); diff --git a/kernel/smpboot.c b/kernel/smpboot.c index d264f59bff56..79f07014be6e 100644 --- a/kernel/smpboot.c +++ b/kernel/smpboot.c @@ -186,6 +186,11 @@ __smpboot_create_thread(struct smp_hotplug_thread *ht, unsigned int cpu) kfree(td); return PTR_ERR(tsk); } + /* + * Park the thread so that it could start right on the CPU + * when it is available. + */ + kthread_park(tsk); get_task_struct(tsk); *per_cpu_ptr(ht->store, cpu) = tsk; if (ht->create) { -- 1.8.5.6 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2016-01-25 16:11 UTC|newest] Thread overview: 82+ messages / expand[flat|nested] mbox.gz Atom feed top 2016-01-25 15:44 [PATCH v4 00/22] kthread: Use kthread worker API more widely Petr Mladek 2016-01-25 15:44 ` Petr Mladek 2016-01-25 15:44 ` Petr Mladek 2016-01-25 15:44 ` [PATCH v4 01/22] timer: Allow to check when the timer callback has not finished yet Petr Mladek 2016-01-25 15:44 ` Petr Mladek 2016-01-25 18:44 ` Tejun Heo 2016-01-25 18:44 ` Tejun Heo 2016-01-25 15:44 ` Petr Mladek [this message] 2016-01-25 15:44 ` [PATCH v4 02/22] kthread/smpboot: Do not park in kthread_create_on_cpu() Petr Mladek 2016-01-25 15:44 ` [PATCH v4 03/22] kthread: Allow to call __kthread_create_on_node() with va_list args Petr Mladek 2016-01-25 15:44 ` Petr Mladek 2016-01-25 15:44 ` [PATCH v4 04/22] kthread: Add create_kthread_worker*() Petr Mladek 2016-01-25 15:44 ` Petr Mladek 2016-01-25 18:53 ` Tejun Heo 2016-01-25 18:53 ` Tejun Heo 2016-02-16 15:44 ` Petr Mladek 2016-02-16 15:44 ` Petr Mladek 2016-02-16 16:08 ` Tejun Heo 2016-02-16 16:08 ` Tejun Heo 2016-02-16 16:08 ` Tejun Heo 2016-02-16 16:10 ` Petr Mladek 2016-02-16 16:10 ` Petr Mladek 2016-02-16 16:10 ` Petr Mladek 2016-01-25 15:44 ` [PATCH v4 05/22] kthread: Add drain_kthread_worker() Petr Mladek 2016-01-25 15:44 ` Petr Mladek 2016-01-25 15:44 ` [PATCH v4 06/22] kthread: Add destroy_kthread_worker() Petr Mladek 2016-01-25 15:44 ` Petr Mladek 2016-01-25 15:44 ` [PATCH v4 07/22] kthread: Detect when a kthread work is used by more workers Petr Mladek 2016-01-25 15:44 ` Petr Mladek 2016-01-25 18:57 ` Tejun Heo 2016-01-25 18:57 ` Tejun Heo 2016-01-25 18:57 ` Tejun Heo 2016-02-16 16:38 ` Petr Mladek 2016-02-16 16:38 ` Petr Mladek 2016-02-16 16:38 ` Petr Mladek 2016-01-25 15:44 ` [PATCH v4 08/22] kthread: Initial support for delayed kthread work Petr Mladek 2016-01-25 15:44 ` Petr Mladek 2016-01-25 19:04 ` Tejun Heo 2016-01-25 19:04 ` Tejun Heo 2016-01-25 19:04 ` Tejun Heo 2016-01-25 15:44 ` [PATCH v4 09/22] kthread: Allow to cancel " Petr Mladek 2016-01-25 15:44 ` Petr Mladek 2016-01-25 19:17 ` Tejun Heo 2016-01-25 19:17 ` Tejun Heo 2016-02-19 16:22 ` Petr Mladek 2016-02-19 16:22 ` Petr Mladek 2016-01-25 15:44 ` [PATCH v4 10/22] kthread: Allow to modify delayed " Petr Mladek 2016-01-25 15:44 ` Petr Mladek 2016-01-25 19:19 ` Tejun Heo 2016-01-25 19:19 ` Tejun Heo 2016-01-25 15:45 ` [PATCH v4 11/22] kthread: Better support freezable kthread workers Petr Mladek 2016-01-25 15:45 ` Petr Mladek 2016-01-25 19:21 ` Tejun Heo 2016-01-25 19:21 ` Tejun Heo 2016-01-25 15:45 ` [PATCH v4 12/22] kthread: Use try_lock_kthread_work() in flush_kthread_work() Petr Mladek 2016-01-25 15:45 ` Petr Mladek 2016-01-25 15:45 ` [PATCH v4 13/22] mm/huge_page: Convert khugepaged() into kthread worker API Petr Mladek 2016-01-25 15:45 ` Petr Mladek 2016-01-25 15:45 ` Petr Mladek 2016-01-25 15:45 ` [PATCH v4 14/22] ring_buffer: Convert benchmark kthreads " Petr Mladek 2016-01-25 15:45 ` Petr Mladek 2016-01-25 15:45 ` [PATCH v4 15/22] hung_task: Convert hungtaskd " Petr Mladek 2016-01-25 15:45 ` Petr Mladek 2016-01-25 15:45 ` [PATCH v4 16/22] kmemleak: Convert kmemleak kthread " Petr Mladek 2016-01-25 15:45 ` Petr Mladek 2016-01-25 15:45 ` [PATCH v4 17/22] ipmi: Convert kipmi " Petr Mladek 2016-01-25 15:45 ` Petr Mladek 2016-01-25 15:45 ` [PATCH v4 18/22] IB/fmr_pool: Convert the cleanup thread " Petr Mladek 2016-01-25 15:45 ` Petr Mladek 2016-01-25 15:45 ` [PATCH v4 19/22] memstick/r592: Better synchronize debug messages in r592_io kthread Petr Mladek 2016-01-25 15:45 ` Petr Mladek 2016-01-25 15:45 ` Petr Mladek 2016-01-25 15:45 ` [PATCH v4 20/22] memstick/r592: convert r592_io kthread into kthread worker API Petr Mladek 2016-01-25 15:45 ` Petr Mladek 2016-01-25 15:45 ` [PATCH v4 21/22] thermal/intel_powerclamp: Remove duplicated code that starts the kthread Petr Mladek 2016-01-25 15:45 ` Petr Mladek 2016-01-25 16:23 ` Jacob Pan 2016-01-25 16:23 ` Jacob Pan 2016-01-25 15:45 ` [PATCH v4 22/22] thermal/intel_powerclamp: Convert the kthread to kthread worker API Petr Mladek 2016-01-25 15:45 ` Petr Mladek 2016-01-25 16:28 ` Jacob Pan 2016-01-25 16:28 ` Jacob Pan
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