Messages in this thread Patch in this message | | | From | Vineeth Remanan Pillai <> | Subject | [RFC PATCH v3 06/16] sched/fair: Export newidle_balance() | Date | Wed, 29 May 2019 20:36:42 +0000 |
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From: Peter Zijlstra <peterz@infradead.org>
For pick_next_task_fair() it is the newidle balance that requires dropping the rq->lock; provided we do put_prev_task() early, we can also detect the condition for doing newidle early.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> --- kernel/sched/fair.c | 18 ++++++++---------- kernel/sched/sched.h | 4 ++++ 2 files changed, 12 insertions(+), 10 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 56fc2a1aa261..49707b4797de 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -3615,8 +3615,6 @@ static inline unsigned long cfs_rq_load_avg(struct cfs_rq *cfs_rq) return cfs_rq->avg.load_avg; } -static int idle_balance(struct rq *this_rq, struct rq_flags *rf); - static inline unsigned long task_util(struct task_struct *p) { return READ_ONCE(p->se.avg.util_avg); @@ -7087,11 +7085,10 @@ done: __maybe_unused; return p; idle: - update_misfit_status(NULL, rq); - new_tasks = idle_balance(rq, rf); + new_tasks = newidle_balance(rq, rf); /* - * Because idle_balance() releases (and re-acquires) rq->lock, it is + * Because newidle_balance() releases (and re-acquires) rq->lock, it is * possible for any higher priority task to appear. In that case we * must re-start the pick_next_entity() loop. */ @@ -9286,10 +9283,10 @@ static int load_balance(int this_cpu, struct rq *this_rq, ld_moved = 0; /* - * idle_balance() disregards balance intervals, so we could repeatedly - * reach this code, which would lead to balance_interval skyrocketting - * in a short amount of time. Skip the balance_interval increase logic - * to avoid that. + * newidle_balance() disregards balance intervals, so we could + * repeatedly reach this code, which would lead to balance_interval + * skyrocketting in a short amount of time. Skip the balance_interval + * increase logic to avoid that. */ if (env.idle == CPU_NEWLY_IDLE) goto out; @@ -9996,7 +9993,7 @@ static inline void nohz_newidle_balance(struct rq *this_rq) { } * idle_balance is called by schedule() if this_cpu is about to become * idle. Attempts to pull tasks from other CPUs. */ -static int idle_balance(struct rq *this_rq, struct rq_flags *rf) +int newidle_balance(struct rq *this_rq, struct rq_flags *rf) { unsigned long next_balance = jiffies + HZ; int this_cpu = this_rq->cpu; @@ -10004,6 +10001,7 @@ static int idle_balance(struct rq *this_rq, struct rq_flags *rf) int pulled_task = 0; u64 curr_cost = 0; + update_misfit_status(NULL, this_rq); /* * We must set idle_stamp _before_ calling idle_balance(), such that we * measure the duration of idle_balance() as idle time. diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index fb01c77c16ff..bfcbcbb25646 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1414,10 +1414,14 @@ static inline void unregister_sched_domain_sysctl(void) } #endif +extern int newidle_balance(struct rq *this_rq, struct rq_flags *rf); + #else static inline void sched_ttwu_pending(void) { } +static inline int newidle_balance(struct rq *this_rq, struct rq_flags *rf) { return 0; } + #endif /* CONFIG_SMP */ #include "stats.h" -- 2.17.1
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