From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932347AbdKOOVY (ORCPT ); Wed, 15 Nov 2017 09:21:24 -0500 Received: from smtp.codeaurora.org ([198.145.29.96]:42376 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756360AbdKOOVL (ORCPT ); Wed, 15 Nov 2017 09:21:11 -0500 DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 3641860376 Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=prsood@codeaurora.org From: Prateek Sood To: peterz@infradead.org, longman@redhat.com, tj@kernel.org, lizefan@huawei.com, mingo@kernel.org, boqun.feng@gmail.com, tglx@linutronix.de Cc: cgroups@vger.kernel.org, sramana@codeaurora.org, linux-kernel@vger.kernel.org, clingutla@codeaurora.org, prsood@codeaurora.org Subject: [PATCH v3 2/2] cpuset: Make cpuset hotplug synchronous Date: Wed, 15 Nov 2017 19:50:15 +0530 Message-Id: <1510755615-25906-3-git-send-email-prsood@codeaurora.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1510755615-25906-1-git-send-email-prsood@codeaurora.org> References: <20171115103742.xt7muaq2dfrs2cyd@hirez.programming.kicks-ass.net> <1510755615-25906-1-git-send-email-prsood@codeaurora.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Convert cpuset_hotplug_workfn() into synchronous call for cpu hotplug path. For memory hotplug path it still gets queued as a work item. Since cpuset_hotplug_workfn() can be made synchronous for cpu hotplug path, it is not required to wait for cpuset hotplug while thawing processes. Signed-off-by: Prateek Sood --- include/linux/cpuset.h | 6 ------ kernel/cgroup/cpuset.c | 41 ++++++++++++++++++++--------------------- kernel/power/process.c | 2 -- kernel/sched/core.c | 1 - 4 files changed, 20 insertions(+), 30 deletions(-) diff --git a/include/linux/cpuset.h b/include/linux/cpuset.h index 1b8e415..2ab910f 100644 --- a/include/linux/cpuset.h +++ b/include/linux/cpuset.h @@ -52,9 +52,7 @@ static inline void cpuset_dec(void) extern int cpuset_init(void); extern void cpuset_init_smp(void); -extern void cpuset_force_rebuild(void); extern void cpuset_update_active_cpus(void); -extern void cpuset_wait_for_hotplug(void); extern void cpuset_cpus_allowed(struct task_struct *p, struct cpumask *mask); extern void cpuset_cpus_allowed_fallback(struct task_struct *p); extern nodemask_t cpuset_mems_allowed(struct task_struct *p); @@ -167,15 +165,11 @@ static inline void set_mems_allowed(nodemask_t nodemask) static inline int cpuset_init(void) { return 0; } static inline void cpuset_init_smp(void) {} -static inline void cpuset_force_rebuild(void) { } - static inline void cpuset_update_active_cpus(void) { partition_sched_domains(1, NULL, NULL); } -static inline void cpuset_wait_for_hotplug(void) { } - static inline void cpuset_cpus_allowed(struct task_struct *p, struct cpumask *mask) { diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index cab5fd1..227bc25 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -2277,15 +2277,8 @@ static void cpuset_hotplug_update_tasks(struct cpuset *cs) mutex_unlock(&cpuset_mutex); } -static bool force_rebuild; - -void cpuset_force_rebuild(void) -{ - force_rebuild = true; -} - /** - * cpuset_hotplug_workfn - handle CPU/memory hotunplug for a cpuset + * cpuset_hotplug - handle CPU/memory hotunplug for a cpuset * * This function is called after either CPU or memory configuration has * changed and updates cpuset accordingly. The top_cpuset is always @@ -2300,7 +2293,7 @@ void cpuset_force_rebuild(void) * Note that CPU offlining during suspend is ignored. We don't modify * cpusets across suspend/resume cycles at all. */ -static void cpuset_hotplug_workfn(struct work_struct *work) +static void cpuset_hotplug(bool use_cpu_hp_lock) { static cpumask_t new_cpus; static nodemask_t new_mems; @@ -2358,25 +2351,31 @@ static void cpuset_hotplug_workfn(struct work_struct *work) } /* rebuild sched domains if cpus_allowed has changed */ - if (cpus_updated || force_rebuild) { - force_rebuild = false; - rebuild_sched_domains(); + if (cpus_updated) { + if (use_cpu_hp_lock) + rebuild_sched_domains(); + else { + /* Acquiring cpu_hotplug_lock is not required. + * When cpuset_hotplug() is called in hotplug path, + * cpu_hotplug_lock is held by the hotplug context + * which is waiting for cpuhp_thread_fun to indicate + * completion of callback. + */ + mutex_lock(&cpuset_mutex); + rebuild_sched_domains_cpuslocked(); + mutex_unlock(&cpuset_mutex); + } } } -void cpuset_update_active_cpus(void) +static void cpuset_hotplug_workfn(struct work_struct *work) { - /* - * We're inside cpu hotplug critical region which usually nests - * inside cgroup synchronization. Bounce actual hotplug processing - * to a work item to avoid reverse locking order. - */ - schedule_work(&cpuset_hotplug_work); + cpuset_hotplug(true); } -void cpuset_wait_for_hotplug(void) +void cpuset_update_active_cpus(void) { - flush_work(&cpuset_hotplug_work); + cpuset_hotplug(false); } /* diff --git a/kernel/power/process.c b/kernel/power/process.c index 7381d49..c326d72 100644 --- a/kernel/power/process.c +++ b/kernel/power/process.c @@ -204,8 +204,6 @@ void thaw_processes(void) __usermodehelper_set_disable_depth(UMH_FREEZING); thaw_workqueues(); - cpuset_wait_for_hotplug(); - read_lock(&tasklist_lock); for_each_process_thread(g, p) { /* No other threads should have PF_SUSPEND_TASK set */ diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 5b82a00..efcf753 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -5600,7 +5600,6 @@ static void cpuset_cpu_active(void) * restore the original sched domains by considering the * cpuset configurations. */ - cpuset_force_rebuild(); } cpuset_update_active_cpus(); } -- Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc., is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.