Commit-ID: 59efa0bac9cf8b2ef8d08f7632826c6d90f6a9bb
Gitweb: http://git.kernel.org/tip/59efa0bac9cf8b2ef8d08f7632826c6d90f6a9bb
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate: Tue, 10 May 2016 18:24:37 +0200
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Thu, 12 May 2016 09:55:31 +0200
sched/core: Kill sched_class::task_waking to clean up the migration logic
With sched_class::task_waking being called only when we do
set_task_cpu(), we can make sched_class::migrate_task_rq() do the work
and eliminate sched_class::task_waking entirely.
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Andrew Hunter <ahh@xxxxxxxxxx>
Cc: Ben Segall <bsegall@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Matt Fleming <matt@xxxxxxxxxxxxxxxxxxx>
Cc: Mike Galbraith <efault@xxxxxx>
Cc: Mike Galbraith <umgwanakikbuti@xxxxxxxxx>
Cc: Morten Rasmussen <morten.rasmussen@xxxxxxx>
Cc: Paul Turner <pjt@xxxxxxxxxx>
Cc: Pavan Kondeti <pkondeti@xxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: byungchul.park@xxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
kernel/sched/core.c | 9 +-------
kernel/sched/fair.c | 58 +++++++++++++++++++++++++---------------------------
kernel/sched/sched.h | 7 +++----
3 files changed, 32 insertions(+), 42 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 1f73e25..636c4b9 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1717,11 +1717,8 @@ ttwu_do_activate(struct rq *rq, struct task_struct *p, int wake_flags,
if (p->sched_contributes_to_load)
rq->nr_uninterruptible--;
- /*
- * If we migrated; we must have called sched_class::task_waking().
- */
if (wake_flags & WF_MIGRATED)
- en_flags |= ENQUEUE_WAKING;
+ en_flags |= ENQUEUE_MIGRATED;
#endif
ttwu_activate(rq, p, en_flags);
@@ -2049,10 +2046,6 @@ try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags)
cpu = select_task_rq(p, p->wake_cpu, SD_BALANCE_WAKE, wake_flags);
if (task_cpu(p) != cpu) {
wake_flags |= WF_MIGRATED;
-
- if (p->sched_class->task_waking)
- p->sched_class->task_waking(p);
-
set_task_cpu(p, cpu);
}
#endif /* CONFIG_SMP */
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 445bcd2..24ce01b 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -3273,7 +3273,7 @@ static inline void check_schedstat_required(void)
*
* WAKEUP (remote)
*
- * ->task_waking_fair()
+ * ->migrate_task_rq_fair() (p->state == TASK_WAKING)
* vruntime -= min_vruntime
*
* enqueue
@@ -3292,7 +3292,7 @@ enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
* Update the normalized vruntime before updating min_vruntime
* through calling update_curr().
*/
- if (!(flags & ENQUEUE_WAKEUP) || (flags & ENQUEUE_WAKING))
+ if (!(flags & ENQUEUE_WAKEUP) || (flags & ENQUEUE_MIGRATED))
se->vruntime += cfs_rq->min_vruntime;
/*
@@ -4841,33 +4841,6 @@ static unsigned long cpu_avg_load_per_task(int cpu)
return 0;
}
-/*
- * Called to migrate a waking task; as blocked tasks retain absolute vruntime
- * the migration needs to deal with this by subtracting the old and adding the
- * new min_vruntime -- the latter is done by enqueue_entity() when placing
- * the task on the new runqueue.
- */
-static void task_waking_fair(struct task_struct *p)
-{
- struct sched_entity *se = &p->se;
- struct cfs_rq *cfs_rq = cfs_rq_of(se);
- u64 min_vruntime;
-
-#ifndef CONFIG_64BIT
- u64 min_vruntime_copy;
-
- do {
- min_vruntime_copy = cfs_rq->min_vruntime_copy;
- smp_rmb();
- min_vruntime = cfs_rq->min_vruntime;
- } while (min_vruntime != min_vruntime_copy);
-#else
- min_vruntime = cfs_rq->min_vruntime;
-#endif
-
- se->vruntime -= min_vruntime;
-}
-
#ifdef CONFIG_FAIR_GROUP_SCHED
/*
* effective_load() calculates the load change as seen from the root_task_group
@@ -5403,6 +5376,32 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_f
static void migrate_task_rq_fair(struct task_struct *p)
{
/*
+ * As blocked tasks retain absolute vruntime the migration needs to
+ * deal with this by subtracting the old and adding the new
+ * min_vruntime -- the latter is done by enqueue_entity() when placing
+ * the task on the new runqueue.
+ */
+ if (p->state == TASK_WAKING) {
+ struct sched_entity *se = &p->se;
+ struct cfs_rq *cfs_rq = cfs_rq_of(se);
+ u64 min_vruntime;
+
+#ifndef CONFIG_64BIT
+ u64 min_vruntime_copy;
+
+ do {
+ min_vruntime_copy = cfs_rq->min_vruntime_copy;
+ smp_rmb();
+ min_vruntime = cfs_rq->min_vruntime;
+ } while (min_vruntime != min_vruntime_copy);
+#else
+ min_vruntime = cfs_rq->min_vruntime;
+#endif
+
+ se->vruntime -= min_vruntime;
+ }
+
+ /*
* We are supposed to update the task to "current" time, then its up to date
* and ready to go to new CPU/cfs_rq. But we have difficulty in getting
* what current time is, so simply throw away the out-of-date time. This
@@ -8672,7 +8671,6 @@ const struct sched_class fair_sched_class = {
.rq_online = rq_online_fair,
.rq_offline = rq_offline_fair,
- .task_waking = task_waking_fair,
.task_dead = task_dead_fair,
.set_cpus_allowed = set_cpus_allowed_common,
#endif
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index ab6adb1..e51145e 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -1168,7 +1168,7 @@ extern const u32 sched_prio_to_wmult[40];
*
* ENQUEUE_HEAD - place at front of runqueue (tail if not specified)
* ENQUEUE_REPLENISH - CBS (replenish runtime and postpone deadline)
- * ENQUEUE_WAKING - sched_class::task_waking was called
+ * ENQUEUE_MIGRATED - the task was migrated during wakeup
*
*/
@@ -1183,9 +1183,9 @@ extern const u32 sched_prio_to_wmult[40];
#define ENQUEUE_HEAD 0x08
#define ENQUEUE_REPLENISH 0x10
#ifdef CONFIG_SMP
-#define ENQUEUE_WAKING 0x20
+#define ENQUEUE_MIGRATED 0x20
#else
-#define ENQUEUE_WAKING 0x00
+#define ENQUEUE_MIGRATED 0x00
#endif
#define RETRY_TASK ((void *)-1UL)
@@ -1217,7 +1217,6 @@ struct sched_class {
int (*select_task_rq)(struct task_struct *p, int task_cpu, int sd_flag, int flags);
void (*migrate_task_rq)(struct task_struct *p);
- void (*task_waking) (struct task_struct *task);
void (*task_woken) (struct rq *this_rq, struct task_struct *task);
void (*set_cpus_allowed)(struct task_struct *p,
--
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