Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759995AbXEXMLf (ORCPT ); Thu, 24 May 2007 08:11:35 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756363AbXEXMKW (ORCPT ); Thu, 24 May 2007 08:10:22 -0400 Received: from il.qumranet.com ([82.166.9.18]:36439 "EHLO il.qumranet.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755982AbXEXMKS (ORCPT ); Thu, 24 May 2007 08:10:18 -0400 From: Avi Kivity To: kvm-devel@lists.sourceforge.net Cc: linux-kernel@vger.kernel.org, shaohua.li@intel.com, lhcs-devel@lists.sourceforge.net, Avi Kivity Subject: [PATCH 1/7] HOTPLUG: Add CPU_DYING notifier Date: Thu, 24 May 2007 15:10:09 +0300 Message-Id: <11800086153311-git-send-email-avi@qumranet.com> X-Mailer: git-send-email 1.5.0.6 In-Reply-To: <1180008615579-git-send-email-avi@qumranet.com> References: <1180008615579-git-send-email-avi@qumranet.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3145 Lines: 88 KVM wants a notification when a cpu is about to die, so it can disable hardware extensions, but at a time when user processes cannot be scheduled on the cpu, so it doesn't try to use virtualization extensions after they have been disabled. This adds a CPU_DYING notification. The notification is called in atomic context on the doomed cpu. Signed-off-by: Avi Kivity --- include/linux/notifier.h | 3 +++ kernel/cpu.c | 16 ++++++++++++++-- 2 files changed, 17 insertions(+), 2 deletions(-) diff --git a/include/linux/notifier.h b/include/linux/notifier.h index 9431101..576f2bb 100644 --- a/include/linux/notifier.h +++ b/include/linux/notifier.h @@ -196,6 +196,8 @@ extern int __srcu_notifier_call_chain(struct srcu_notifier_head *nh, #define CPU_DEAD 0x0007 /* CPU (unsigned)v dead */ #define CPU_LOCK_ACQUIRE 0x0008 /* Acquire all hotcpu locks */ #define CPU_LOCK_RELEASE 0x0009 /* Release all hotcpu locks */ +#define CPU_DYING 0x000A /* CPU (unsigned)v not running any task, + * not handling interrupts, soon dead */ /* Used for CPU hotplug events occuring while tasks are frozen due to a suspend * operation in progress @@ -208,6 +210,7 @@ extern int __srcu_notifier_call_chain(struct srcu_notifier_head *nh, #define CPU_DOWN_PREPARE_FROZEN (CPU_DOWN_PREPARE | CPU_TASKS_FROZEN) #define CPU_DOWN_FAILED_FROZEN (CPU_DOWN_FAILED | CPU_TASKS_FROZEN) #define CPU_DEAD_FROZEN (CPU_DEAD | CPU_TASKS_FROZEN) +#define CPU_DYING_FROZEN (CPU_DYING | CPU_TASKS_FROZEN) #endif /* __KERNEL__ */ #endif /* _LINUX_NOTIFIER_H */ diff --git a/kernel/cpu.c b/kernel/cpu.c index 208cf34..181ae70 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -103,11 +103,19 @@ static inline void check_for_tasks(int cpu) write_unlock_irq(&tasklist_lock); } +struct take_cpu_down_param { + unsigned long mod; + void *hcpu; +}; + /* Take this CPU down. */ -static int take_cpu_down(void *unused) +static int take_cpu_down(void *_param) { + struct take_cpu_down_param *param = _param; int err; + raw_notifier_call_chain(&cpu_chain, CPU_DYING | param->mod, + param->hcpu); /* Ensure this CPU doesn't handle any more interrupts. */ err = __cpu_disable(); if (err < 0) @@ -127,6 +135,10 @@ static int _cpu_down(unsigned int cpu, int tasks_frozen) cpumask_t old_allowed, tmp; void *hcpu = (void *)(long)cpu; unsigned long mod = tasks_frozen ? CPU_TASKS_FROZEN : 0; + struct take_cpu_down_param tcd_param = { + .mod = mod, + .hcpu = hcpu, + }; if (num_online_cpus() == 1) return -EBUSY; @@ -153,7 +165,7 @@ static int _cpu_down(unsigned int cpu, int tasks_frozen) set_cpus_allowed(current, tmp); mutex_lock(&cpu_bitmask_lock); - p = __stop_machine_run(take_cpu_down, NULL, cpu); + p = __stop_machine_run(take_cpu_down, &tcd_param, cpu); mutex_unlock(&cpu_bitmask_lock); if (IS_ERR(p) || cpu_online(cpu)) { -- 1.5.0.6 - 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/