[tip:sched/core] sched: Replace all_pinned with a generic flags field

From: tip-bot for Peter Zijlstra
Date: Wed Dec 21 2011 - 06:42:25 EST


Commit-ID: 5b54b56be5b540a9cb12682c4d0df5454c098a38
Gitweb: http://git.kernel.org/tip/5b54b56be5b540a9cb12682c4d0df5454c098a38
Author: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
AuthorDate: Thu, 22 Sep 2011 15:23:13 +0200
Committer: Ingo Molnar <mingo@xxxxxxx>
CommitDate: Wed, 21 Dec 2011 10:34:45 +0100

sched: Replace all_pinned with a generic flags field

Replace the all_pinned argument with a flags field so that we can add
some extra controls throughout that entire call chain.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Link: http://lkml.kernel.org/n/tip-33kevm71m924ok1gpxd720v3@xxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
kernel/sched/fair.c | 35 +++++++++++++++++++----------------
1 files changed, 19 insertions(+), 16 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 2237ffe..be47ce6 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -3131,13 +3131,15 @@ task_hot(struct task_struct *p, u64 now, struct sched_domain *sd)
return delta < (s64)sysctl_sched_migration_cost;
}

+#define LBF_ALL_PINNED 0x01
+
/*
* can_migrate_task - may task p from runqueue rq be migrated to this_cpu?
*/
static
int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu,
struct sched_domain *sd, enum cpu_idle_type idle,
- int *all_pinned)
+ int *lb_flags)
{
int tsk_cache_hot = 0;
/*
@@ -3150,7 +3152,7 @@ int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu,
schedstat_inc(p, se.statistics.nr_failed_migrations_affine);
return 0;
}
- *all_pinned = 0;
+ *lb_flags &= ~LBF_ALL_PINNED;

if (task_running(rq, p)) {
schedstat_inc(p, se.statistics.nr_failed_migrations_running);
@@ -3224,7 +3226,7 @@ move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest,
static unsigned long
balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
unsigned long max_load_move, struct sched_domain *sd,
- enum cpu_idle_type idle, int *all_pinned,
+ enum cpu_idle_type idle, int *lb_flags,
struct cfs_rq *busiest_cfs_rq)
{
int loops = 0, pulled = 0;
@@ -3240,7 +3242,7 @@ balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,

if ((p->se.load.weight >> 1) > rem_load_move ||
!can_migrate_task(p, busiest, this_cpu, sd, idle,
- all_pinned))
+ lb_flags))
continue;

pull_task(busiest, p, this_rq, this_cpu);
@@ -3359,7 +3361,7 @@ static unsigned long
load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest,
unsigned long max_load_move,
struct sched_domain *sd, enum cpu_idle_type idle,
- int *all_pinned)
+ int *lb_flags)
{
long rem_load_move = max_load_move;
struct cfs_rq *busiest_cfs_rq;
@@ -3383,7 +3385,7 @@ load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest,
rem_load = div_u64(rem_load, busiest_h_load + 1);

moved_load = balance_tasks(this_rq, this_cpu, busiest,
- rem_load, sd, idle, all_pinned,
+ rem_load, sd, idle, lb_flags,
busiest_cfs_rq);

if (!moved_load)
@@ -3409,10 +3411,10 @@ static unsigned long
load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest,
unsigned long max_load_move,
struct sched_domain *sd, enum cpu_idle_type idle,
- int *all_pinned)
+ int *lb_flags)
{
return balance_tasks(this_rq, this_cpu, busiest,
- max_load_move, sd, idle, all_pinned,
+ max_load_move, sd, idle, lb_flags,
&busiest->cfs);
}
#endif
@@ -3427,14 +3429,14 @@ load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest,
static int move_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
unsigned long max_load_move,
struct sched_domain *sd, enum cpu_idle_type idle,
- int *all_pinned)
+ int *lb_flags)
{
unsigned long total_load_moved = 0, load_moved;

do {
load_moved = load_balance_fair(this_rq, this_cpu, busiest,
max_load_move - total_load_moved,
- sd, idle, all_pinned);
+ sd, idle, lb_flags);

total_load_moved += load_moved;

@@ -4439,7 +4441,7 @@ static int load_balance(int this_cpu, struct rq *this_rq,
struct sched_domain *sd, enum cpu_idle_type idle,
int *balance)
{
- int ld_moved, all_pinned = 0, active_balance = 0;
+ int ld_moved, lb_flags = 0, active_balance = 0;
struct sched_group *group;
unsigned long imbalance;
struct rq *busiest;
@@ -4480,11 +4482,11 @@ redo:
* still unbalanced. ld_moved simply stays zero, so it is
* correctly treated as an imbalance.
*/
- all_pinned = 1;
+ lb_flags |= LBF_ALL_PINNED;
local_irq_save(flags);
double_rq_lock(this_rq, busiest);
ld_moved = move_tasks(this_rq, this_cpu, busiest,
- imbalance, sd, idle, &all_pinned);
+ imbalance, sd, idle, &lb_flags);
double_rq_unlock(this_rq, busiest);
local_irq_restore(flags);

@@ -4495,7 +4497,7 @@ redo:
resched_cpu(this_cpu);

/* All tasks on this runqueue were pinned by CPU affinity */
- if (unlikely(all_pinned)) {
+ if (unlikely(lb_flags & LBF_ALL_PINNED)) {
cpumask_clear_cpu(cpu_of(busiest), cpus);
if (!cpumask_empty(cpus))
goto redo;
@@ -4525,7 +4527,7 @@ redo:
tsk_cpus_allowed(busiest->curr))) {
raw_spin_unlock_irqrestore(&busiest->lock,
flags);
- all_pinned = 1;
+ lb_flags |= LBF_ALL_PINNED;
goto out_one_pinned;
}

@@ -4578,7 +4580,8 @@ out_balanced:

out_one_pinned:
/* tune up the balancing interval */
- if ((all_pinned && sd->balance_interval < MAX_PINNED_INTERVAL) ||
+ if (((lb_flags & LBF_ALL_PINNED) &&
+ sd->balance_interval < MAX_PINNED_INTERVAL) ||
(sd->balance_interval < sd->max_interval))
sd->balance_interval *= 2;

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