sched/fair: Make the use of prev_cpu consistent in the wakeup path
In commit:
ac66f54772
("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: Rik van Riel <riel@redhat.com>
Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com>
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: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dietmar.eggemann@arm.com
Cc: linux-kernel@vger.kernel.org
Cc: mgalbraith@suse.de
Cc: vincent.guittot@linaro.org
Cc: yuyang.du@intel.com
Link: http://lkml.kernel.org/r/1466615004-3503-3-git-send-email-morten.rasmussen@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
parent
bd425d4bfc
commit
772bd008cd
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@ -656,7 +656,7 @@ static u64 sched_vslice(struct cfs_rq *cfs_rq, struct sched_entity *se)
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}
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}
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#ifdef CONFIG_SMP
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#ifdef CONFIG_SMP
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static int select_idle_sibling(struct task_struct *p, int cpu);
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static int select_idle_sibling(struct task_struct *p, int prev_cpu, int cpu);
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static unsigned long task_h_load(struct task_struct *p);
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static unsigned long task_h_load(struct task_struct *p);
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/*
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/*
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@ -1512,7 +1512,8 @@ balance:
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* Call select_idle_sibling to maybe find a better one.
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* Call select_idle_sibling to maybe find a better one.
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*/
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*/
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if (!cur)
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if (!cur)
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env->dst_cpu = select_idle_sibling(env->p, env->dst_cpu);
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env->dst_cpu = select_idle_sibling(env->p, env->src_cpu,
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env->dst_cpu);
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assign:
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assign:
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task_numa_assign(env, cur, imp);
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task_numa_assign(env, cur, imp);
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@ -5101,18 +5102,18 @@ static int wake_wide(struct task_struct *p)
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return 1;
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return 1;
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}
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}
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static int wake_affine(struct sched_domain *sd, struct task_struct *p, int sync)
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static int wake_affine(struct sched_domain *sd, struct task_struct *p,
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int prev_cpu, int sync)
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{
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{
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s64 this_load, load;
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s64 this_load, load;
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s64 this_eff_load, prev_eff_load;
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s64 this_eff_load, prev_eff_load;
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int idx, this_cpu, prev_cpu;
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int idx, this_cpu;
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struct task_group *tg;
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struct task_group *tg;
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unsigned long weight;
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unsigned long weight;
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int balanced;
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int balanced;
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idx = sd->wake_idx;
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idx = sd->wake_idx;
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this_cpu = smp_processor_id();
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this_cpu = smp_processor_id();
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prev_cpu = task_cpu(p);
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load = source_load(prev_cpu, idx);
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load = source_load(prev_cpu, idx);
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this_load = target_load(this_cpu, idx);
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this_load = target_load(this_cpu, idx);
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@ -5277,11 +5278,10 @@ find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu)
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/*
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/*
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* Try and locate an idle CPU in the sched_domain.
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* Try and locate an idle CPU in the sched_domain.
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*/
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*/
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static int select_idle_sibling(struct task_struct *p, int target)
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static int select_idle_sibling(struct task_struct *p, int prev, int target)
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{
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{
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struct sched_domain *sd;
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struct sched_domain *sd;
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struct sched_group *sg;
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struct sched_group *sg;
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int i = task_cpu(p);
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if (idle_cpu(target))
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if (idle_cpu(target))
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return target;
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return target;
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@ -5289,8 +5289,8 @@ static int select_idle_sibling(struct task_struct *p, int target)
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/*
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/*
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* If the prevous cpu is cache affine and idle, don't be stupid.
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* If the prevous cpu is cache affine and idle, don't be stupid.
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*/
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*/
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if (i != target && cpus_share_cache(i, target) && idle_cpu(i))
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if (prev != target && cpus_share_cache(prev, target) && idle_cpu(prev))
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return i;
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return prev;
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/*
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/*
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* Otherwise, iterate the domains and find an eligible idle cpu.
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* Otherwise, iterate the domains and find an eligible idle cpu.
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@ -5311,6 +5311,8 @@ static int select_idle_sibling(struct task_struct *p, int target)
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for_each_lower_domain(sd) {
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for_each_lower_domain(sd) {
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sg = sd->groups;
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sg = sd->groups;
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do {
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do {
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int i;
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if (!cpumask_intersects(sched_group_cpus(sg),
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if (!cpumask_intersects(sched_group_cpus(sg),
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tsk_cpus_allowed(p)))
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tsk_cpus_allowed(p)))
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goto next;
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goto next;
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@ -5419,13 +5421,13 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_f
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if (affine_sd) {
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if (affine_sd) {
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sd = NULL; /* Prefer wake_affine over balance flags */
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sd = NULL; /* Prefer wake_affine over balance flags */
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if (cpu != prev_cpu && wake_affine(affine_sd, p, sync))
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if (cpu != prev_cpu && wake_affine(affine_sd, p, prev_cpu, sync))
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new_cpu = cpu;
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new_cpu = cpu;
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}
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}
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if (!sd) {
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if (!sd) {
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if (sd_flag & SD_BALANCE_WAKE) /* XXX always ? */
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if (sd_flag & SD_BALANCE_WAKE) /* XXX always ? */
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new_cpu = select_idle_sibling(p, new_cpu);
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new_cpu = select_idle_sibling(p, prev_cpu, new_cpu);
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} else while (sd) {
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} else while (sd) {
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struct sched_group *group;
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struct sched_group *group;
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