From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1423099AbcBZStl (ORCPT ); Fri, 26 Feb 2016 13:49:41 -0500 Received: from www.linutronix.de ([62.245.132.108]:33374 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1422858AbcBZSoz (ORCPT ); Fri, 26 Feb 2016 13:44:55 -0500 Message-Id: <20160226182340.770651526@linutronix.de> User-Agent: quilt/0.63-1 Date: Fri, 26 Feb 2016 18:43:29 -0000 From: Thomas Gleixner To: LKML Cc: Linus Torvalds , Andrew Morton , Ingo Molnar , Peter Zijlstra , Peter Anvin , Oleg Nesterov , linux-arch@vger.kernel.org, Tejun Heo , Steven Rostedt , Rusty Russell , Paul McKenney , Rafael Wysocki , Arjan van de Ven , Rik van Riel , "Srivatsa S. Bhat" , Sebastian Siewior , Paul Turner Subject: [patch 07/20] cpu/hotplug: Convert the hotplugged cpu work to a state machine References: <20160226164321.657646833@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Disposition: inline; filename=cpu-hotplug-Convert-the-hotplugged-processor-work-to.patch X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001,URIBL_BLOCKED=0.001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Move the functions which need to run on the hotplugged processor into a state machine array and let the code iterate through these functions. In a later state, this will grow synchronization points between the control processor and the hotplugged processor, so we can move the various architecture implementations of the synchronizations to the core. Signed-off-by: Thomas Gleixner --- include/linux/cpuhotplug.h | 4 ++ kernel/cpu.c | 81 ++++++++++++++++++++++++++++++++++++--------- 2 files changed, 70 insertions(+), 15 deletions(-) Index: b/include/linux/cpuhotplug.h =================================================================== --- a/include/linux/cpuhotplug.h +++ b/include/linux/cpuhotplug.h @@ -6,6 +6,10 @@ enum cpuhp_state { CPUHP_CREATE_THREADS, CPUHP_NOTIFY_PREPARE, CPUHP_BRINGUP_CPU, + CPUHP_AP_OFFLINE, + CPUHP_AP_NOTIFY_STARTING, + CPUHP_AP_ONLINE, + CPUHP_TEARDOWN_CPU, CPUHP_NOTIFY_ONLINE, CPUHP_ONLINE, }; Index: b/kernel/cpu.c =================================================================== --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -57,6 +57,7 @@ struct cpuhp_step { }; static struct cpuhp_step cpuhp_bp_states[]; +static struct cpuhp_step cpuhp_ap_states[]; /** * cpuhp_invoke_callback _ Invoke the callbacks for a given state @@ -304,6 +305,12 @@ static int notify_online(unsigned int cp return 0; } +static int notify_starting(unsigned int cpu) +{ + cpu_notify(CPU_STARTING, cpu); + return 0; +} + static int bringup_cpu(unsigned int cpu) { struct task_struct *idle = idle_thread_get(cpu); @@ -421,9 +428,17 @@ static int notify_down_prepare(unsigned return err; } +static int notify_dying(unsigned int cpu) +{ + cpu_notify(CPU_DYING, cpu); + return 0; +} + /* Take this CPU down. */ static int take_cpu_down(void *_param) { + struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); + enum cpuhp_state target = max((int)st->target, CPUHP_AP_OFFLINE); int err, cpu = smp_processor_id(); /* Ensure this CPU doesn't handle any more interrupts. */ @@ -431,7 +446,12 @@ static int take_cpu_down(void *_param) if (err < 0) return err; - cpu_notify(CPU_DYING, cpu); + /* Invoke the former CPU_DYING callbacks */ + for (; st->state > target; st->state--) { + struct cpuhp_step *step = cpuhp_ap_states + st->state; + + cpuhp_invoke_callback(cpu, st->state, step->teardown); + } /* Give up timekeeping duties */ tick_handover_do_timer(); /* Park the stopper thread */ @@ -512,6 +532,7 @@ static int notify_dead(unsigned int cpu) #define notify_down_prepare NULL #define takedown_cpu NULL #define notify_dead NULL +#define notify_dying NULL #endif #ifdef CONFIG_HOTPLUG_CPU @@ -615,6 +636,28 @@ void smpboot_thread_init(void) register_cpu_notifier(&smpboot_thread_notifier); } +/** + * notify_cpu_starting(cpu) - call the CPU_STARTING notifiers + * @cpu: cpu that just started + * + * This function calls the cpu_chain notifiers with CPU_STARTING. + * It must be called by the arch code on the new cpu, before the new cpu + * enables interrupts and before the "boot" cpu returns from __cpu_up(). + */ +void notify_cpu_starting(unsigned int cpu) +{ + struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); + enum cpuhp_state target = min((int)st->target, CPUHP_AP_ONLINE); + + while (st->state < target) { + struct cpuhp_step *step; + + st->state++; + step = cpuhp_ap_states + st->state; + cpuhp_invoke_callback(cpu, st->state, step->startup); + } +} + static void undo_cpu_up(unsigned int cpu, struct cpuhp_cpu_state *st) { for (st->state--; st->state > st->target; st->state--) { @@ -842,19 +885,6 @@ core_initcall(cpu_hotplug_pm_sync_init); #endif /* CONFIG_PM_SLEEP_SMP */ -/** - * notify_cpu_starting(cpu) - call the CPU_STARTING notifiers - * @cpu: cpu that just started - * - * This function calls the cpu_chain notifiers with CPU_STARTING. - * It must be called by the arch code on the new cpu, before the new cpu - * enables interrupts and before the "boot" cpu returns from __cpu_up(). - */ -void notify_cpu_starting(unsigned int cpu) -{ - cpu_notify(CPU_STARTING, cpu); -} - #endif /* CONFIG_SMP */ /* Boot processor state steps */ @@ -879,8 +909,12 @@ static struct cpuhp_step cpuhp_bp_states [CPUHP_BRINGUP_CPU] = { .name = "cpu:bringup", .startup = bringup_cpu, + .teardown = NULL, + }, + [CPUHP_TEARDOWN_CPU] = { + .name = "cpu:teardown", + .startup = NULL, .teardown = takedown_cpu, - .skip_onerr = true, }, [CPUHP_NOTIFY_ONLINE] = { .name = "notify:online", @@ -889,6 +923,23 @@ static struct cpuhp_step cpuhp_bp_states }, #endif [CPUHP_ONLINE] = { + .name = "online", + .startup = NULL, + .teardown = NULL, + }, +}; + +/* Application processor state steps */ +static struct cpuhp_step cpuhp_ap_states[] = { +#ifdef CONFIG_SMP + [CPUHP_AP_NOTIFY_STARTING] = { + .name = "notify:starting", + .startup = notify_starting, + .teardown = notify_dying, + .skip_onerr = true, + }, +#endif + [CPUHP_ONLINE] = { .name = "online", .startup = NULL, .teardown = NULL,