From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965350AbbHKQZG (ORCPT ); Tue, 11 Aug 2015 12:25:06 -0400 Received: from e28smtp05.in.ibm.com ([122.248.162.5]:46376 "EHLO e28smtp05.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965076AbbHKQZE (ORCPT ); Tue, 11 Aug 2015 12:25:04 -0400 X-Helo: d28dlp03.in.ibm.com X-MailFrom: srikar@linux.vnet.ibm.com X-RcptTo: linux-kernel@vger.kernel.org From: Srikar Dronamraju To: Ingo Molnar , Peter Zijlstra Cc: linux-kernel@vger.kernel.org, srikar@linux.vnet.ibm.com, Rik van Riel , Mel Gorman Subject: [PATCH v2 4/4] sched/numa: Convert sched_numa_balancing to a static_branch Date: Tue, 11 Aug 2015 21:54:21 +0530 Message-Id: <1439310261-16124-1-git-send-email-srikar@linux.vnet.ibm.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1439290813-6683-1-git-send-email-srikar@linux.vnet.ibm.com> References: <1439290813-6683-1-git-send-email-srikar@linux.vnet.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 15081116-0017-0000-0000-000006A88F77 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Variable sched_numa_balancing toggles numa_balancing feature. Hence moving from a simple read mostly variable to a more apt static_branch. Suggested-by: Peter Zijlstra Signed-off-by: Srikar Dronamraju --- kernel/sched/core.c | 10 +++++++--- kernel/sched/fair.c | 6 +++--- kernel/sched/sched.h | 6 +----- 3 files changed, 11 insertions(+), 11 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index d02570b..5f330d5 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2057,12 +2057,16 @@ static void __sched_fork(unsigned long clone_flags, struct task_struct *p) #endif /* CONFIG_NUMA_BALANCING */ } +DEFINE_STATIC_KEY_FALSE(sched_numa_balancing); + #ifdef CONFIG_NUMA_BALANCING -__read_mostly bool sched_numa_balancing; void set_numabalancing_state(bool enabled) { - sched_numa_balancing = enabled; + if (enabled) + static_branch_enable(&sched_numa_balancing); + else + static_branch_disable(&sched_numa_balancing); } #ifdef CONFIG_PROC_SYSCTL @@ -2071,7 +2075,7 @@ int sysctl_numa_balancing(struct ctl_table *table, int write, { struct ctl_table t; int err; - int state = sched_numa_balancing; + int state = static_branch_likely(&sched_numa_balancing); if (write && !capable(CAP_SYS_ADMIN)) return -EPERM; diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index f67f2bc..aab730e 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -2069,7 +2069,7 @@ void task_numa_fault(int last_cpupid, int mem_node, int pages, int flags) int local = !!(flags & TNF_FAULT_LOCAL); int priv; - if (!sched_numa_balancing) + if (!static_branch_likely(&sched_numa_balancing)) return; /* for example, ksmd faulting in a user's mm */ @@ -5524,7 +5524,7 @@ static int migrate_degrades_locality(struct task_struct *p, struct lb_env *env) unsigned long src_faults, dst_faults; int src_nid, dst_nid; - if (!sched_numa_balancing) + if (!static_branch_likely(&sched_numa_balancing)) return -1; if (!p->numa_faults || !(env->sd->flags & SD_NUMA)) @@ -7810,7 +7810,7 @@ static void task_tick_fair(struct rq *rq, struct task_struct *curr, int queued) entity_tick(cfs_rq, se, queued); } - if (sched_numa_balancing) + if (!static_branch_unlikely(&sched_numa_balancing)) task_tick_numa(rq, curr); } diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 953be0f..72cae5d 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1003,11 +1003,7 @@ extern struct static_key sched_feat_keys[__SCHED_FEAT_NR]; #define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x)) #endif /* SCHED_DEBUG && HAVE_JUMP_LABEL */ -#ifdef CONFIG_NUMA_BALANCING -extern bool sched_numa_balancing; -#else -#define sched_numa_balancing (0) -#endif /* CONFIG_NUMA_BALANCING */ +extern struct static_key_false sched_numa_balancing; static inline u64 global_rt_period(void) { -- 1.8.3.1