From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752551AbaH2DoB (ORCPT ); Thu, 28 Aug 2014 23:44:01 -0400 Received: from mga09.intel.com ([134.134.136.24]:22312 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752070AbaH2Dn7 (ORCPT ); Thu, 28 Aug 2014 23:43:59 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.04,422,1406617200"; d="scan'208";a="473683036" Message-ID: <53FFF642.7010909@intel.com> Date: Fri, 29 Aug 2014 11:40:50 +0800 From: Lan Tianyu User-Agent: Mozilla/5.0 (X11; Linux i686 on x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.0 MIME-Version: 1.0 To: peterz@infradead.org, mingo@kernel.org, rafael.j.wysocki@intel.com, srivatsa@mit.edu, akpm@linux-foundation.org, laijs@cn.fujitsu.com, toshi.kani@hp.com, todd.e.brandt@linux.intel.com, wangyun@linux.vnet.ibm.com, ego@linux.vnet.ibm.com, fabf@skynet.be, linux@arm.linux.org.uk CC: oleg@redhat.com, srivatsa.bhat@linux.vnet.ibm.com, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH V2] PM/CPU: Parallel enalbing nonboot cpus with resume devices References: <1408696420-2654-1-git-send-email-tianyu.lan@intel.com> In-Reply-To: <1408696420-2654-1-git-send-email-tianyu.lan@intel.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2014年08月22日 16:33, Lan Tianyu wrote: > In the current world, all nonboot cpus are enabled serially during system > resume. System resume sequence is that boot cpu enables nonboot cpu one by > one and then resume devices. Before resuming devices, there are few tasks > assigned to nonboot cpus after they are brought up. This waste cpu usage. > > To accelerate S3, this patches allows boot cpu to go forward to resume > devices after bringing up one nonboot cpu. The nonboot cpu will be in > charge of bringing up other cpus. This makes enabling cpu2~x parallel > with resuming devices. > > Signed-off-by: Lan Tianyu > --- > Change since V1: > Remove PM_PARALLEL_CPU_UP_FOR_SUSPEND kernel config and make > paralleling cpu as default behaviour. Add error handling for > failure of the first frozen cpu online. > > So far, I just tested the patch on the Intel machines. It's better > to test it on the others Arch platforms. Appreciate a lot if some > one can help test it. > Hi All: Any comments on this patch? Thanks. > kernel/cpu.c | 70 +++++++++++++++++++++++++++++++++++++++++++++++++----------- > 1 file changed, 58 insertions(+), 12 deletions(-) > > diff --git a/kernel/cpu.c b/kernel/cpu.c > index a343bde..9bc8497 100644 > --- a/kernel/cpu.c > +++ b/kernel/cpu.c > @@ -551,8 +551,42 @@ void __weak arch_enable_nonboot_cpus_end(void) > { > } > > +static int _cpu_up_with_trace(int cpu) > +{ > + int error; > + > + trace_suspend_resume(TPS("CPU_ON"), cpu, true); > + error = _cpu_up(cpu, 1); > + trace_suspend_resume(TPS("CPU_ON"), cpu, false); > + if (error) { > + pr_warn("Error taking CPU%d up: %d\n", cpu, error); > + return error; > + } > + > + pr_info("CPU%d is up\n", cpu); > + return 0; > +} > + > +static int async_enable_nonboot_cpus(void *data) > +{ > + int cpu; > + > + cpu_maps_update_begin(); > + arch_enable_nonboot_cpus_begin(); > + > + for_each_cpu(cpu, frozen_cpus) { > + _cpu_up_with_trace(cpu); > + } > + > + arch_enable_nonboot_cpus_end(); > + cpumask_clear(frozen_cpus); > + cpu_maps_update_done(); > + return 0; > +} > + > void __ref enable_nonboot_cpus(void) > { > + struct task_struct *tsk; > int cpu, error; > > /* Allow everyone to use the CPU hotplug again */ > @@ -563,22 +597,34 @@ void __ref enable_nonboot_cpus(void) > > pr_info("Enabling non-boot CPUs ...\n"); > > - arch_enable_nonboot_cpus_begin(); > + cpu = cpumask_first(frozen_cpus); > + cpumask_clear_cpu(cpu, frozen_cpus); > > - for_each_cpu(cpu, frozen_cpus) { > - trace_suspend_resume(TPS("CPU_ON"), cpu, true); > - error = _cpu_up(cpu, 1); > - trace_suspend_resume(TPS("CPU_ON"), cpu, false); > - if (!error) { > - pr_info("CPU%d is up\n", cpu); > - continue; > + error = _cpu_up_with_trace(cpu); > + if (cpumask_empty(frozen_cpus)) > + goto out; > + > + if (error) { > + /* > + * If fail to bring up the first frozen cpus, > + * enable the rest frozen cpus on the boot cpu. > + */ > + arch_enable_nonboot_cpus_begin(); > + for_each_cpu(cpu, frozen_cpus) { > + _cpu_up_with_trace(cpu); > } > - pr_warn("Error taking CPU%d up: %d\n", cpu, error); > - } > + arch_enable_nonboot_cpus_end(); > > - arch_enable_nonboot_cpus_end(); > + } else { > + tsk = kthread_create_on_cpu(async_enable_nonboot_cpus, > + NULL, cpu, "async-enable-nonboot-cpus"); > + if (IS_ERR(tsk)) { > + pr_err("Failed to create async enable nonboot cpus thread.\n"); > + goto out; > + } > > - cpumask_clear(frozen_cpus); > + kthread_unpark(tsk); > + } > out: > cpu_maps_update_done(); > } > -- Best regards Tianyu Lan