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From: Mel Gorman <mgorman@techsingularity.net>
To: Linux-Stable <stable@vger.kernel.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Subject: [PATCH 15/26] sched/topology: Simplify sched_group_mask() usage
Date: Thu, 20 Jul 2017 22:21:33 +0100	[thread overview]
Message-ID: <20170720212144.18453-16-mgorman@techsingularity.net> (raw)
In-Reply-To: <20170720212144.18453-1-mgorman@techsingularity.net>

From: Peter Zijlstra <peterz@infradead.org>

commit af218122b103900fa33d408aea0c2468791e698c upstream.

While writing the comments, it occurred to me that:

  sg_cpus & sg_mask == sg_mask

at least conceptually; the !overlap case sets the all 1s mask. If we
correct that we can simplify things and directly use sg_mask.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
---
 kernel/sched/fair.c     | 7 +++----
 kernel/sched/topology.c | 5 +++--
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index bafa4e04b850..713a3106693e 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -7915,7 +7915,7 @@ static int active_load_balance_cpu_stop(void *data);
 static int should_we_balance(struct lb_env *env)
 {
 	struct sched_group *sg = env->sd->groups;
-	struct cpumask *sg_cpus, *sg_mask;
+	struct cpumask *sg_mask;
 	int cpu, balance_cpu = -1;
 
 	/*
@@ -7925,11 +7925,10 @@ static int should_we_balance(struct lb_env *env)
 	if (env->idle == CPU_NEWLY_IDLE)
 		return 1;
 
-	sg_cpus = sched_group_cpus(sg);
 	sg_mask = sched_group_mask(sg);
 	/* Try to find first idle cpu */
-	for_each_cpu_and(cpu, sg_cpus, env->cpus) {
-		if (!cpumask_test_cpu(cpu, sg_mask) || !idle_cpu(cpu))
+	for_each_cpu_and(cpu, sg_mask, env->cpus) {
+		if (!idle_cpu(cpu))
 			continue;
 
 		balance_cpu = cpu;
diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index dea1950b42a5..bf53a99eb511 100644
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -85,7 +85,8 @@ static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level,
 				group->sgc->id,
 				cpumask_pr_args(sched_group_cpus(group)));
 
-		if ((sd->flags & SD_OVERLAP) && !cpumask_full(sched_group_mask(group))) {
+		if ((sd->flags & SD_OVERLAP) &&
+		    !cpumask_equal(sched_group_mask(group), sched_group_cpus(group))) {
 			printk(KERN_CONT " mask=%*pbl",
 				cpumask_pr_args(sched_group_mask(group)));
 		}
@@ -505,7 +506,7 @@ enum s_alloc {
  */
 int group_balance_cpu(struct sched_group *sg)
 {
-	return cpumask_first_and(sched_group_cpus(sg), sched_group_mask(sg));
+	return cpumask_first(sched_group_mask(sg));
 }
 
 
-- 
2.13.1

  parent reply	other threads:[~2017-07-20 21:21 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-07-20 21:21 [PATCH 00/26] Performance-related backports for 4.12.2 Mel Gorman
2017-07-20 21:21 ` [PATCH 01/26] sched/topology: Refactor function build_overlap_sched_groups() Mel Gorman
2017-07-20 21:21 ` [PATCH 02/26] sched/topology: Fix building of overlapping sched-groups Mel Gorman
2017-07-20 21:21 ` [PATCH 03/26] sched/topology: Simplify build_overlap_sched_groups() Mel Gorman
2017-07-20 21:21 ` [PATCH 04/26] sched/debug: Print the scheduler topology group mask Mel Gorman
2017-07-20 21:21 ` [PATCH 05/26] sched/topology: Verify the first group matches the child domain Mel Gorman
2017-07-20 21:21 ` [PATCH 06/26] sched/topology: Optimize build_group_mask() Mel Gorman
2017-07-20 21:21 ` [PATCH 07/26] sched/topology: Move comment about asymmetric node setups Mel Gorman
2017-07-20 21:21 ` [PATCH 08/26] sched/topology: Remove FORCE_SD_OVERLAP Mel Gorman
2017-07-20 21:21 ` [PATCH 09/26] sched/topology: Fix overlapping sched_group_mask Mel Gorman
2017-07-20 21:21 ` [PATCH 10/26] sched/topology: Small cleanup Mel Gorman
2017-07-20 21:21 ` [PATCH 11/26] sched/topology: Add sched_group_capacity debugging Mel Gorman
2017-07-20 21:21 ` [PATCH 12/26] sched/topology: Fix overlapping sched_group_capacity Mel Gorman
2017-07-20 21:21 ` [PATCH 13/26] sched/topology: Add a few comments Mel Gorman
2017-07-20 21:21 ` [PATCH 14/26] sched/topology: Rewrite get_group() Mel Gorman
2017-07-20 21:21 ` Mel Gorman [this message]
2017-07-20 21:21 ` [PATCH 16/26] sched/topology: Rename sched_group_mask() Mel Gorman
2017-07-20 21:21 ` [PATCH 17/26] sched/topology: Rename sched_group_cpus() Mel Gorman
2017-07-20 21:21 ` [PATCH 18/26] vtime, sched/cputime: Remove vtime_account_user() Mel Gorman
2017-07-20 21:21 ` [PATCH 19/26] sched/cputime: Always set tsk->vtime_snap_whence after accounting vtime Mel Gorman
2017-07-20 21:21 ` [PATCH 20/26] sched/cputime: Rename vtime fields Mel Gorman
2017-07-20 21:21 ` [PATCH 21/26] sched/cputime: Move the vtime task fields to their own struct Mel Gorman
2017-07-20 21:21 ` [PATCH 22/26] sched/cputime: Accumulate vtime on top of nsec clocksource Mel Gorman
2017-07-20 21:21 ` [PATCH 23/26] sched/fair: Fix load_balance() affinity redo path Mel Gorman
2017-07-20 21:21 ` [PATCH 24/26] percpu_counter: Rename __percpu_counter_add to percpu_counter_add_batch Mel Gorman
2017-07-20 21:21 ` [PATCH 25/26] writeback: rework wb_[dec|inc]_stat family of functions Mel Gorman
2017-07-20 21:21 ` [PATCH 26/26] kernel/fork.c: virtually mapped stacks: do not disable interrupts Mel Gorman
2017-07-24 16:44 ` [PATCH 00/26] Performance-related backports for 4.12.2 Mel Gorman
2017-07-24 23:29   ` Greg KH
2017-07-25  8:14     ` Mel Gorman
2017-07-25 15:21       ` Greg KH

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