Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751771Ab2KPCWp (ORCPT ); Thu, 15 Nov 2012 21:22:45 -0500 Received: from mail-vc0-f174.google.com ([209.85.220.174]:61094 "EHLO mail-vc0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751145Ab2KPCVx (ORCPT ); Thu, 15 Nov 2012 21:21:53 -0500 From: Frederic Weisbecker To: LKML Cc: Steven Rostedt , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Andrew Morton , Paul Gortmaker , Frederic Weisbecker Subject: [PATCH 6/9] irq_work: Flush work on CPU_DYING Date: Fri, 16 Nov 2012 03:21:28 +0100 Message-Id: <1353032491-16462-7-git-send-email-fweisbec@gmail.com> X-Mailer: git-send-email 1.7.5.4 In-Reply-To: <1353032491-16462-1-git-send-email-fweisbec@gmail.com> References: <1353032491-16462-1-git-send-email-fweisbec@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3086 Lines: 114 From: Steven Rostedt In order not to offline a CPU with pending irq works, flush the queue from CPU_DYING. The notifier is called by stop_machine on the CPU that is going down. The code will not be called from irq context (so things like get_irq_regs() wont work) but I'm not sure what the requirements are for irq_work in that regard (Peter?). But irqs are disabled and the CPU is about to go offline. Might as well flush the work. Signed-off-by: Steven Rostedt Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Andrew Morton Cc: Paul Gortmaker Signed-off-by: Frederic Weisbecker --- kernel/irq_work.c | 50 ++++++++++++++++++++++++++++++++++++++++++++------ 1 files changed, 44 insertions(+), 6 deletions(-) diff --git a/kernel/irq_work.c b/kernel/irq_work.c index b3c113a..cf8b657 100644 --- a/kernel/irq_work.c +++ b/kernel/irq_work.c @@ -12,6 +12,7 @@ #include #include #include +#include #include /* @@ -110,11 +111,7 @@ bool irq_work_needs_cpu(void) return true; } -/* - * Run the irq_work entries on this cpu. Requires to be ran from hardirq - * context with local IRQs disabled. - */ -void irq_work_run(void) +static void __irq_work_run(void) { struct irq_work *work; struct llist_head *this_list; @@ -124,7 +121,6 @@ void irq_work_run(void) if (llist_empty(this_list)) return; - BUG_ON(!in_irq()); BUG_ON(!irqs_disabled()); llnode = llist_del_all(this_list); @@ -149,6 +145,16 @@ void irq_work_run(void) (void)cmpxchg(&work->flags, IRQ_WORK_BUSY, 0); } } + +/* + * Run the irq_work entries on this cpu. Requires to be ran from hardirq + * context with local IRQs disabled. + */ +void irq_work_run(void) +{ + BUG_ON(!in_irq()); + __irq_work_run(); +} EXPORT_SYMBOL_GPL(irq_work_run); /* @@ -163,3 +169,35 @@ void irq_work_sync(struct irq_work *work) cpu_relax(); } EXPORT_SYMBOL_GPL(irq_work_sync); + +#ifdef CONFIG_HOTPLUG_CPU +static int irq_work_cpu_notify(struct notifier_block *self, + unsigned long action, void *hcpu) +{ + long cpu = (long)hcpu; + + switch (action) { + case CPU_DYING: + /* Called from stop_machine */ + if (WARN_ON_ONCE(cpu != smp_processor_id())) + break; + __irq_work_run(); + break; + default: + break; + } + return NOTIFY_OK; +} + +static struct notifier_block cpu_notify; + +static __init int irq_work_init_cpu_notifier(void) +{ + cpu_notify.notifier_call = irq_work_cpu_notify; + cpu_notify.priority = 0; + register_cpu_notifier(&cpu_notify); + return 0; +} +device_initcall(irq_work_init_cpu_notifier); + +#endif /* CONFIG_HOTPLUG_CPU */ -- 1.7.5.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/