From a0933a372d84e341911f2a09cdb9980584315f03 Mon Sep 17 00:00:00 2001 From: Juri Lelli Date: Fri, 26 Jun 2015 12:14:23 +0100 Subject: [PATCH] sched/{core,fair}: trigger OPP change request on fork() Patch "sched/fair: add triggers for OPP change requests" introduced OPP change triggers for enqueue_task_fair(), but the trigger was operating only for wakeups. Fact is that it makes sense to consider wakeup_new also (i.e., fork()), as we don't know anything about a newly created task and thus we most certainly want to jump to max OPP to not harm performance too much. However, it is not currently possible (or at least it wasn't evident to me how to do so :/) to tell new wakeups from other (non wakeup) operations. This patch introduces an additional flag in sched.h that is only set at fork() time and it is then consumed in enqueue_task_fair() for our purpose. cc: Ingo Molnar cc: Peter Zijlstra Signed-off-by: Juri Lelli Signed-off-by: Steve Muckle --- kernel/sched/core.c | 2 +- kernel/sched/fair.c | 9 +++------ kernel/sched/sched.h | 1 + 3 files changed, 5 insertions(+), 7 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 69a36dd165e2..569a2f0f01e4 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2387,7 +2387,7 @@ void wake_up_new_task(struct task_struct *p) #endif rq = __task_rq_lock(p); - activate_task(rq, p, 0); + activate_task(rq, p, ENQUEUE_WAKEUP_NEW); p->on_rq = TASK_ON_RQ_QUEUED; trace_sched_wakeup_new(p); check_preempt_curr(rq, p, WF_FORK); diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index eba576fe527a..4558c6ac2a66 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -4187,7 +4187,8 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags) { struct cfs_rq *cfs_rq; struct sched_entity *se = &p->se; - int task_new = !(flags & ENQUEUE_WAKEUP); + int task_new = flags & ENQUEUE_WAKEUP_NEW; + int task_wakeup = flags & ENQUEUE_WAKEUP; for_each_sched_entity(se) { if (se->on_rq) @@ -4231,12 +4232,8 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags) * because we get here also during load balancing, but * in these cases it seems wise to trigger as single * request after load balancing is done. - * - * XXX: how about fork()? Do we need a special - * flag/something to tell if we are here after a - * fork() (wakeup_task_new)? */ - if (!task_new) + if (task_new || task_wakeup) update_capacity_of(cpu_of(rq)); } hrtick_update(rq); diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index a96fcea5d98b..c91e85c90d5d 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1181,6 +1181,7 @@ static const u32 prio_to_wmult[40] = { #endif #define ENQUEUE_REPLENISH 0x08 #define ENQUEUE_RESTORE 0x10 +#define ENQUEUE_WAKEUP_NEW 0x20 #define DEQUEUE_SLEEP 0x01 #define DEQUEUE_SAVE 0x02 -- 2.34.1