From: Morten Rasmussen <morten.rasmussen@arm.com>
To: peterz@infradead.org, mingo@redhat.com
Cc: dietmar.eggemann@arm.com, yuyang.du@intel.com,
vincent.guittot@linaro.org, mgalbraith@suse.de,
linux-kernel@vger.kernel.org,
Morten Rasmussen <morten.rasmussen@arm.com>,
Rik van Riel <riel@redhat.com>
Subject: [PATCH v2 02/13] sched/fair: Consistent use of prev_cpu in wakeup path
Date: Wed, 22 Jun 2016 18:03:13 +0100 [thread overview]
Message-ID: <1466615004-3503-3-git-send-email-morten.rasmussen@arm.com> (raw)
In-Reply-To: <1466615004-3503-1-git-send-email-morten.rasmussen@arm.com>
In commit ac66f5477239 ("sched/numa: Introduce migrate_swap()")
select_task_rq() got a 'cpu' argument to enable overriding of prev_cpu
in special cases (NUMA task swapping). However, the
select_task_rq_fair() helper functions: wake_affine() and
select_idle_sibling(), still use task_cpu(p) directly to work out
prev_cpu which leads to inconsistencies.
This patch passes prev_cpu (potentially overridden by NUMA code) into
the helper functions to ensure prev_cpu is indeed the same cpu
everywhere in the wakeup path.
cc: Ingo Molnar <mingo@redhat.com>
cc: Peter Zijlstra <peterz@infradead.org>
cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com>
---
kernel/sched/fair.c | 24 +++++++++++++-----------
1 file changed, 13 insertions(+), 11 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index c6dd8bab010c..eec8e29104f9 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -656,7 +656,7 @@ static u64 sched_vslice(struct cfs_rq *cfs_rq, struct sched_entity *se)
}
#ifdef CONFIG_SMP
-static int select_idle_sibling(struct task_struct *p, int cpu);
+static int select_idle_sibling(struct task_struct *p, int prev_cpu, int cpu);
static unsigned long task_h_load(struct task_struct *p);
/*
@@ -1483,7 +1483,8 @@ static void task_numa_compare(struct task_numa_env *env,
* Call select_idle_sibling to maybe find a better one.
*/
if (!cur)
- env->dst_cpu = select_idle_sibling(env->p, env->dst_cpu);
+ env->dst_cpu = select_idle_sibling(env->p, env->src_cpu,
+ env->dst_cpu);
assign:
task_numa_assign(env, cur, imp);
@@ -4985,18 +4986,18 @@ static int wake_wide(struct task_struct *p)
return 1;
}
-static int wake_affine(struct sched_domain *sd, struct task_struct *p, int sync)
+static int wake_affine(struct sched_domain *sd, struct task_struct *p,
+ int prev_cpu, int sync)
{
s64 this_load, load;
s64 this_eff_load, prev_eff_load;
- int idx, this_cpu, prev_cpu;
+ int idx, this_cpu;
struct task_group *tg;
unsigned long weight;
int balanced;
idx = sd->wake_idx;
this_cpu = smp_processor_id();
- prev_cpu = task_cpu(p);
load = source_load(prev_cpu, idx);
this_load = target_load(this_cpu, idx);
@@ -5161,11 +5162,10 @@ find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu)
/*
* Try and locate an idle CPU in the sched_domain.
*/
-static int select_idle_sibling(struct task_struct *p, int target)
+static int select_idle_sibling(struct task_struct *p, int prev, int target)
{
struct sched_domain *sd;
struct sched_group *sg;
- int i = task_cpu(p);
if (idle_cpu(target))
return target;
@@ -5173,8 +5173,8 @@ static int select_idle_sibling(struct task_struct *p, int target)
/*
* If the prevous cpu is cache affine and idle, don't be stupid.
*/
- if (i != target && cpus_share_cache(i, target) && idle_cpu(i))
- return i;
+ if (prev != target && cpus_share_cache(prev, target) && idle_cpu(prev))
+ return prev;
/*
* Otherwise, iterate the domains and find an eligible idle cpu.
@@ -5195,6 +5195,8 @@ static int select_idle_sibling(struct task_struct *p, int target)
for_each_lower_domain(sd) {
sg = sd->groups;
do {
+ int i;
+
if (!cpumask_intersects(sched_group_cpus(sg),
tsk_cpus_allowed(p)))
goto next;
@@ -5303,13 +5305,13 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_f
if (affine_sd) {
sd = NULL; /* Prefer wake_affine over balance flags */
- if (cpu != prev_cpu && wake_affine(affine_sd, p, sync))
+ if (cpu != prev_cpu && wake_affine(affine_sd, p, prev_cpu, sync))
new_cpu = cpu;
}
if (!sd) {
if (sd_flag & SD_BALANCE_WAKE) /* XXX always ? */
- new_cpu = select_idle_sibling(p, new_cpu);
+ new_cpu = select_idle_sibling(p, prev_cpu, new_cpu);
} else while (sd) {
struct sched_group *group;
--
1.9.1
next prev parent reply other threads:[~2016-06-22 17:02 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-22 17:03 [PATCH v2 00/13] sched: Clean-ups and asymmetric cpu capacity support Morten Rasmussen
2016-06-22 17:03 ` [PATCH v2 01/13] sched: Fix power to capacity renaming in comment Morten Rasmussen
2016-08-10 18:03 ` [tip:sched/core] sched/core: " tip-bot for Morten Rasmussen
2016-06-22 17:03 ` Morten Rasmussen [this message]
2016-06-22 18:04 ` [PATCH v2 02/13] sched/fair: Consistent use of prev_cpu in wakeup path Rik van Riel
2016-06-23 9:56 ` Morten Rasmussen
2016-06-23 12:24 ` Rik van Riel
2016-08-10 18:03 ` [tip:sched/core] sched/fair: Make the use of prev_cpu consistent in the " tip-bot for Morten Rasmussen
2016-06-22 17:03 ` [PATCH v2 03/13] sched/fair: Optimize find_idlest_cpu() when there is no choice Morten Rasmussen
2016-07-13 12:20 ` Vincent Guittot
2016-08-10 18:03 ` [tip:sched/core] " tip-bot for Morten Rasmussen
2016-06-22 17:03 ` [PATCH v2 04/13] sched: Introduce SD_ASYM_CPUCAPACITY sched_domain topology flag Morten Rasmussen
2016-07-11 9:55 ` Peter Zijlstra
2016-07-11 10:42 ` Morten Rasmussen
2016-06-22 17:03 ` [PATCH v2 05/13] sched: Enable SD_BALANCE_WAKE for asymmetric capacity systems Morten Rasmussen
2016-07-11 10:04 ` Peter Zijlstra
2016-07-11 10:37 ` Morten Rasmussen
2016-07-11 11:04 ` Morten Rasmussen
2016-07-11 11:24 ` Peter Zijlstra
2016-07-12 14:26 ` Morten Rasmussen
2016-06-22 17:03 ` [PATCH v2 06/13] sched: Store maximum per-cpu capacity in root domain Morten Rasmussen
2016-07-11 10:18 ` Peter Zijlstra
2016-07-11 16:16 ` Dietmar Eggemann
2016-07-12 11:42 ` Peter Zijlstra
2016-07-13 11:18 ` Dietmar Eggemann
2016-07-13 12:40 ` Vincent Guittot
2016-07-13 13:48 ` Dietmar Eggemann
2016-07-13 16:37 ` Morten Rasmussen
2016-07-14 13:25 ` Vincent Guittot
2016-07-14 15:15 ` Morten Rasmussen
2016-07-15 11:46 ` Morten Rasmussen
2016-07-15 13:39 ` Vincent Guittot
2016-07-15 16:02 ` Morten Rasmussen
2016-07-18 12:48 ` Vincent Guittot
2016-07-18 15:11 ` Morten Rasmussen
2016-06-22 17:03 ` [PATCH v2 07/13] sched/fair: Let asymmetric cpu configurations balance at wake-up Morten Rasmussen
2016-07-11 11:13 ` Peter Zijlstra
2016-07-11 12:32 ` Morten Rasmussen
2016-07-13 12:56 ` Vincent Guittot
2016-07-13 16:14 ` Morten Rasmussen
2016-07-14 13:45 ` Vincent Guittot
2016-07-15 8:37 ` Morten Rasmussen
2016-06-22 17:03 ` [PATCH v2 08/13] sched/fair: Compute task/cpu utilization at wake-up more correctly Morten Rasmussen
2016-06-22 17:03 ` [PATCH v2 09/13] sched/fair: Consider spare capacity in find_idlest_group() Morten Rasmussen
2016-06-22 17:03 ` [PATCH v2 10/13] sched: Add per-cpu max capacity to sched_group_capacity Morten Rasmussen
2016-06-22 17:03 ` [PATCH v2 11/13] sched/fair: Avoid pulling tasks from non-overloaded higher capacity groups Morten Rasmussen
2016-06-23 21:20 ` Sai Gurrappadi
2016-06-30 7:49 ` Morten Rasmussen
2016-07-14 16:39 ` Sai Gurrappadi
2016-07-15 8:39 ` Morten Rasmussen
2016-07-12 12:59 ` Peter Zijlstra
2016-07-12 14:34 ` Morten Rasmussen
2016-06-22 17:03 ` [PATCH v2 12/13] arm: Set SD_ASYM_CPUCAPACITY for big.LITTLE platforms Morten Rasmussen
2016-06-22 17:03 ` [PATCH v2 13/13] arm: Update arch_scale_cpu_capacity() to reflect change to define Morten Rasmussen
2016-06-28 10:20 ` [PATCH v2 00/13] sched: Clean-ups and asymmetric cpu capacity support Koan-Sin Tan
2016-06-30 7:53 ` Morten Rasmussen
2016-07-08 7:35 ` KEITA KOBAYASHI
2016-07-08 8:18 ` Morten Rasmussen
2016-07-11 8:33 ` Morten Rasmussen
2016-07-11 12:44 ` Vincent Guittot
2016-07-12 13:25 ` Peter Zijlstra
2016-07-12 14:39 ` Morten Rasmussen
2016-07-13 12:06 ` Vincent Guittot
2016-07-13 15:54 ` Morten Rasmussen
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