From patchwork Sat May 11 11:57:18 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Robin Holt X-Patchwork-Id: 2553661 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork2.kernel.org Received: from casper.infradead.org (casper.infradead.org [85.118.1.10]) by patchwork2.kernel.org (Postfix) with ESMTP id 6A511DF230 for ; Sat, 11 May 2013 11:59:29 +0000 (UTC) Received: from merlin.infradead.org ([2001:4978:20e::2]) by casper.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1Ub8Ro-0008Fe-NN; Sat, 11 May 2013 11:58:45 +0000 Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1Ub8RX-0001y2-CO; Sat, 11 May 2013 11:58:27 +0000 Received: from relay2.sgi.com ([192.48.179.30] helo=relay.sgi.com) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1Ub8R5-0001tC-6v for linux-arm-kernel@lists.infradead.org; Sat, 11 May 2013 11:58:01 +0000 Received: from estes.americas.sgi.com (estes.americas.sgi.com [128.162.236.10]) by relay2.corp.sgi.com (Postfix) with ESMTP id ED231304077; Sat, 11 May 2013 04:57:38 -0700 (PDT) Received: from asylum.americas.sgi.com (asylum.americas.sgi.com [128.162.246.107]) by estes.americas.sgi.com (Postfix) with ESMTP id CAFEA7002FBF; Sat, 11 May 2013 06:57:38 -0500 (CDT) Received: by asylum.americas.sgi.com (Postfix, from userid 1641) id C6CE5826054; Sat, 11 May 2013 06:57:38 -0500 (CDT) From: Robin Holt To: Andrew Morton Subject: [PATCH -v10 02/11] Migrate shutdown/reboot to boot cpu. Date: Sat, 11 May 2013 06:57:18 -0500 Message-Id: <1368273447-11958-3-git-send-email-holt@sgi.com> X-Mailer: git-send-email 1.8.2.1 In-Reply-To: <1368273447-11958-1-git-send-email-holt@sgi.com> References: <1368273447-11958-1-git-send-email-holt@sgi.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20130511_075759_350368_A00B1B1F X-CRM114-Status: GOOD ( 17.79 ) X-Spam-Score: -5.7 (-----) X-Spam-Report: SpamAssassin version 3.3.2 on merlin.infradead.org summary: Content analysis details: (-5.7 points) pts rule name description ---- ---------------------- -------------------------------------------------- -2.3 RCVD_IN_DNSWL_MED RBL: Sender listed at http://www.dnswl.org/, medium trust [192.48.179.30 listed in list.dnswl.org] -1.4 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Cc: Russ Anderson , Russell King , the arch/x86 maintainers , Linux Kernel Mailing List , stable@vger.kernel.org, Robin Holt , "H. Peter Anvin" , Guan Xuetao , Arm Mailing List X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org We recently noticed that reboot of a 1024 cpu machine takes approx 16 minutes of just stopping the cpus. The slowdown was tracked to commit f96972f. The current implementation does all the work of hot removing the cpus before halting the system. We are switching to just migrating to the boot cpu and then continuing with shutdown/reboot. This also has the effect of not breaking x86's command line parameter for specifying the reboot cpu. Note, this code was shamelessly copied from arch/x86/kernel/reboot.c with bits removed pertaining to the reboot_cpu command line parameter. Signed-off-by: Robin Holt Tested-by: Shawn Guo To: Andrew Morton Cc: H. Peter Anvin Cc: Russ Anderson Cc: Robin Holt Cc: Russell King Cc: Guan Xuetao Cc: Linux Kernel Mailing List Cc: the arch/x86 maintainers Cc: Arm Mailing List Cc: --- Changes since -v8 - Change stack parameter to make future patches cleaner. Changes since -v6: - Add #define for PF_THREAD_BOUND as compatibility to make stable easier. - Fixup s/reboot_cpu_id/reboot_cpu/ --- kernel/sys.c | 29 ++++++++++++++++++++++++++--- 1 file changed, 26 insertions(+), 3 deletions(-) diff --git a/kernel/sys.c b/kernel/sys.c index b95d3c7..2bbd9a7 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -362,6 +362,29 @@ int unregister_reboot_notifier(struct notifier_block *nb) } EXPORT_SYMBOL(unregister_reboot_notifier); +/* Add backwards compatibility for stable trees. */ +#ifndef PF_NO_SETAFFINITY +#define PF_NO_SETAFFINITY PF_THREAD_BOUND +#endif + +static void migrate_to_reboot_cpu(void) +{ + /* The boot cpu is always logical cpu 0 */ + int cpu = 0; + + cpu_hotplug_disable(); + + /* Make certain the cpu I'm about to reboot on is online */ + if (!cpu_online(cpu)) + cpu = cpumask_first(cpu_online_mask); + + /* Prevent races with other tasks migrating this task */ + current->flags |= PF_NO_SETAFFINITY; + + /* Make certain I only run on the appropriate processor */ + set_cpus_allowed_ptr(current, cpumask_of(cpu)); +} + /** * kernel_restart - reboot the system * @cmd: pointer to buffer containing command to execute for restart @@ -373,7 +396,7 @@ EXPORT_SYMBOL(unregister_reboot_notifier); void kernel_restart(char *cmd) { kernel_restart_prepare(cmd); - disable_nonboot_cpus(); + migrate_to_reboot_cpu(); syscore_shutdown(); if (!cmd) printk(KERN_EMERG "Restarting system.\n"); @@ -400,7 +423,7 @@ static void kernel_shutdown_prepare(enum system_states state) void kernel_halt(void) { kernel_shutdown_prepare(SYSTEM_HALT); - disable_nonboot_cpus(); + migrate_to_reboot_cpu(); syscore_shutdown(); printk(KERN_EMERG "System halted.\n"); kmsg_dump(KMSG_DUMP_HALT); @@ -419,7 +442,7 @@ void kernel_power_off(void) kernel_shutdown_prepare(SYSTEM_POWER_OFF); if (pm_power_off_prepare) pm_power_off_prepare(); - disable_nonboot_cpus(); + migrate_to_reboot_cpu(); syscore_shutdown(); printk(KERN_EMERG "Power down.\n"); kmsg_dump(KMSG_DUMP_POWEROFF);