From: Vineeth Remanan Pillai <vpillai@digitalocean.com>
To: Nishanth Aravamudan <naravamudan@digitalocean.com>,
Julien Desfossez <jdesfossez@digitalocean.com>,
Peter Zijlstra <peterz@infradead.org>,
Tim Chen <tim.c.chen@linux.intel.com>,
mingo@kernel.org, tglx@linutronix.de, pjt@google.com,
torvalds@linux-foundation.org
Cc: linux-kernel@vger.kernel.org, subhra.mazumdar@oracle.com,
fweisbec@gmail.com, keescook@chromium.org, kerrnel@google.com,
Phil Auld <pauld@redhat.com>, Aaron Lu <aaron.lwe@gmail.com>,
Aubrey Li <aubrey.intel@gmail.com>,
Valentin Schneider <valentin.schneider@arm.com>,
Mel Gorman <mgorman@techsingularity.net>,
Pawan Gupta <pawan.kumar.gupta@linux.intel.com>,
Paolo Bonzini <pbonzini@redhat.com>
Subject: [RFC PATCH v2 15/17] sched: Trivial forced-newidle balancer
Date: Tue, 23 Apr 2019 16:18:20 +0000 [thread overview]
Message-ID: <002304fa58577c7926abe9f4cdc8039945985b3d.1556025155.git.vpillai@digitalocean.com> (raw)
In-Reply-To: <cover.1556025155.git.vpillai@digitalocean.com>
In-Reply-To: <cover.1556025155.git.vpillai@digitalocean.com>
From: Peter Zijlstra (Intel) <peterz@infradead.org>
When a sibling is forced-idle to match the core-cookie; search for
matching tasks to fill the core.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
include/linux/sched.h | 1 +
kernel/sched/core.c | 131 +++++++++++++++++++++++++++++++++++++++++-
kernel/sched/idle.c | 1 +
kernel/sched/sched.h | 6 ++
4 files changed, 138 insertions(+), 1 deletion(-)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index a4b39a28236f..1a309e8546cd 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -641,6 +641,7 @@ struct task_struct {
#ifdef CONFIG_SCHED_CORE
struct rb_node core_node;
unsigned long core_cookie;
+ unsigned int core_occupation;
#endif
#ifdef CONFIG_CGROUP_SCHED
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 9e6e90c6f9b9..e8f5ec641d0a 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -217,6 +217,21 @@ struct task_struct *sched_core_find(struct rq *rq, unsigned long cookie)
return match;
}
+struct task_struct *sched_core_next(struct task_struct *p, unsigned long cookie)
+{
+ struct rb_node *node = &p->core_node;
+
+ node = rb_next(node);
+ if (!node)
+ return NULL;
+
+ p = container_of(node, struct task_struct, core_node);
+ if (p->core_cookie != cookie)
+ return NULL;
+
+ return p;
+}
+
/*
* The static-key + stop-machine variable are needed such that:
*
@@ -3672,7 +3687,7 @@ pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
struct task_struct *next, *max = NULL;
const struct sched_class *class;
const struct cpumask *smt_mask;
- int i, j, cpu;
+ int i, j, cpu, occ = 0;
if (!sched_core_enabled(rq))
return __pick_next_task(rq, prev, rf);
@@ -3763,6 +3778,9 @@ pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
goto done;
}
+ if (!is_idle_task(p))
+ occ++;
+
rq_i->core_pick = p;
/*
@@ -3786,6 +3804,7 @@ pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
cpu_rq(j)->core_pick = NULL;
}
+ occ = 1;
goto again;
}
}
@@ -3808,6 +3827,8 @@ next_class:;
WARN_ON_ONCE(!rq_i->core_pick);
+ rq_i->core_pick->core_occupation = occ;
+
if (i == cpu)
continue;
@@ -3823,6 +3844,114 @@ next_class:;
return next;
}
+static bool try_steal_cookie(int this, int that)
+{
+ struct rq *dst = cpu_rq(this), *src = cpu_rq(that);
+ struct task_struct *p;
+ unsigned long cookie;
+ bool success = false;
+
+ local_irq_disable();
+ double_rq_lock(dst, src);
+
+ cookie = dst->core->core_cookie;
+ if (!cookie)
+ goto unlock;
+
+ if (dst->curr != dst->idle)
+ goto unlock;
+
+ p = sched_core_find(src, cookie);
+ if (p == src->idle)
+ goto unlock;
+
+ do {
+ if (p == src->core_pick || p == src->curr)
+ goto next;
+
+ if (!cpumask_test_cpu(this, &p->cpus_allowed))
+ goto next;
+
+ if (p->core_occupation > dst->idle->core_occupation)
+ goto next;
+
+ p->on_rq = TASK_ON_RQ_MIGRATING;
+ deactivate_task(src, p, 0);
+ set_task_cpu(p, this);
+ activate_task(dst, p, 0);
+ p->on_rq = TASK_ON_RQ_QUEUED;
+
+ resched_curr(dst);
+
+ success = true;
+ break;
+
+next:
+ p = sched_core_next(p, cookie);
+ } while (p);
+
+unlock:
+ double_rq_unlock(dst, src);
+ local_irq_enable();
+
+ return success;
+}
+
+static bool steal_cookie_task(int cpu, struct sched_domain *sd)
+{
+ int i;
+
+ for_each_cpu_wrap(i, sched_domain_span(sd), cpu) {
+ if (i == cpu)
+ continue;
+
+ if (need_resched())
+ break;
+
+ if (try_steal_cookie(cpu, i))
+ return true;
+ }
+
+ return false;
+}
+
+static void sched_core_balance(struct rq *rq)
+{
+ struct sched_domain *sd;
+ int cpu = cpu_of(rq);
+
+ rcu_read_lock();
+ raw_spin_unlock_irq(rq_lockp(rq));
+ for_each_domain(cpu, sd) {
+ if (!(sd->flags & SD_LOAD_BALANCE))
+ break;
+
+ if (need_resched())
+ break;
+
+ if (steal_cookie_task(cpu, sd))
+ break;
+ }
+ raw_spin_lock_irq(rq_lockp(rq));
+ rcu_read_unlock();
+}
+
+static DEFINE_PER_CPU(struct callback_head, core_balance_head);
+
+void queue_core_balance(struct rq *rq)
+{
+ if (!sched_core_enabled(rq))
+ return;
+
+ if (!rq->core->core_cookie)
+ return;
+
+ if (!rq->nr_running) /* not forced idle */
+ return;
+
+ queue_balance_callback(rq, &per_cpu(core_balance_head, rq->cpu), sched_core_balance);
+}
+
#else /* !CONFIG_SCHED_CORE */
static struct task_struct *
diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
index e7f38da60373..44decdcccba1 100644
--- a/kernel/sched/idle.c
+++ b/kernel/sched/idle.c
@@ -387,6 +387,7 @@ static void set_next_task_idle(struct rq *rq, struct task_struct *next)
{
update_idle_core(rq);
schedstat_inc(rq->sched_goidle);
+ queue_core_balance(rq);
}
static struct task_struct *
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 4cfde289610d..2a5f5a6b11ae 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -1013,6 +1013,8 @@ static inline raw_spinlock_t *rq_lockp(struct rq *rq)
return &rq->__lock;
}
+extern void queue_core_balance(struct rq *rq);
+
#else /* !CONFIG_SCHED_CORE */
static inline bool sched_core_enabled(struct rq *rq)
@@ -1025,6 +1027,10 @@ static inline raw_spinlock_t *rq_lockp(struct rq *rq)
return &rq->__lock;
}
+static inline void queue_core_balance(struct rq *rq)
+{
+}
+
#endif /* CONFIG_SCHED_CORE */
#ifdef CONFIG_SCHED_SMT
--
2.17.1
next prev parent reply other threads:[~2019-04-23 16:19 UTC|newest]
Thread overview: 109+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-23 16:18 [RFC PATCH v2 00/17] Core scheduling v2 Vineeth Remanan Pillai
2019-04-23 16:18 ` [RFC PATCH v2 01/17] stop_machine: Fix stop_cpus_in_progress ordering Vineeth Remanan Pillai
2019-04-23 16:18 ` [RFC PATCH v2 02/17] sched: Fix kerneldoc comment for ia64_set_curr_task Vineeth Remanan Pillai
2019-04-23 16:18 ` [RFC PATCH v2 03/17] sched: Wrap rq::lock access Vineeth Remanan Pillai
2019-04-23 16:18 ` [RFC PATCH v2 04/17] sched/{rt,deadline}: Fix set_next_task vs pick_next_task Vineeth Remanan Pillai
2019-04-23 16:18 ` [RFC PATCH v2 05/17] sched: Add task_struct pointer to sched_class::set_curr_task Vineeth Remanan Pillai
2019-04-23 16:18 ` [RFC PATCH v2 06/17] sched/fair: Export newidle_balance() Vineeth Remanan Pillai
2019-04-23 16:18 ` [RFC PATCH v2 07/17] sched: Allow put_prev_task() to drop rq->lock Vineeth Remanan Pillai
2019-04-23 16:18 ` [RFC PATCH v2 08/17] sched: Rework pick_next_task() slow-path Vineeth Remanan Pillai
2019-04-23 16:18 ` [RFC PATCH v2 09/17] sched: Introduce sched_class::pick_task() Vineeth Remanan Pillai
2019-04-26 14:02 ` Peter Zijlstra
2019-04-26 16:10 ` Vineeth Remanan Pillai
2019-04-29 5:38 ` Aaron Lu
2019-04-23 16:18 ` [RFC PATCH v2 10/17] sched: Core-wide rq->lock Vineeth Remanan Pillai
2019-04-23 16:18 ` [RFC PATCH v2 11/17] sched: Basic tracking of matching tasks Vineeth Remanan Pillai
2019-04-24 0:08 ` Tim Chen
2019-04-24 20:43 ` Vineeth Remanan Pillai
2019-04-24 22:12 ` Tim Chen
2019-04-25 14:35 ` Phil Auld
2019-05-22 19:52 ` Vineeth Remanan Pillai
2019-04-24 0:17 ` Tim Chen
2019-04-24 20:43 ` Vineeth Remanan Pillai
2019-04-29 3:36 ` Aaron Lu
2019-05-10 13:06 ` Peter Zijlstra
2019-04-29 6:15 ` Aaron Lu
2019-05-01 23:27 ` Tim Chen
2019-05-03 0:06 ` Tim Chen
2019-05-08 15:49 ` Aubrey Li
2019-05-08 18:19 ` Subhra Mazumdar
2019-05-08 18:37 ` Subhra Mazumdar
2019-05-09 0:01 ` Aubrey Li
2019-05-09 0:25 ` Subhra Mazumdar
2019-05-09 1:38 ` Aubrey Li
2019-05-09 2:14 ` Subhra Mazumdar
2019-05-09 15:10 ` Aubrey Li
2019-05-09 17:50 ` Subhra Mazumdar
2019-05-10 0:09 ` Tim Chen
2019-04-23 16:18 ` [RFC PATCH v2 12/17] sched: A quick and dirty cgroup tagging interface Vineeth Remanan Pillai
2019-04-25 14:26 ` Phil Auld
2019-04-26 14:13 ` Peter Zijlstra
2019-04-26 14:19 ` Phil Auld
2019-05-10 15:12 ` Julien Desfossez
2019-04-23 16:18 ` [RFC PATCH v2 13/17] sched: Add core wide task selection and scheduling Vineeth Remanan Pillai
2019-04-29 7:13 ` Aaron Lu
2019-05-18 15:37 ` Aubrey Li
2019-05-20 13:04 ` Phil Auld
2019-05-20 14:04 ` Vineeth Pillai
2019-05-21 8:19 ` Aubrey Li
2019-05-21 13:24 ` Vineeth Pillai
2019-04-23 16:18 ` [RFC PATCH v2 14/17] sched/fair: Add a few assertions Vineeth Remanan Pillai
2019-04-23 16:18 ` Vineeth Remanan Pillai [this message]
2019-04-23 23:46 ` [RFC PATCH v2 15/17] sched: Trivial forced-newidle balancer Aubrey Li
2019-04-24 14:03 ` Vineeth Remanan Pillai
2019-04-24 14:05 ` Vineeth Remanan Pillai
2019-04-23 16:18 ` [RFC PATCH v2 16/17] sched: Wake up sibling if it has something to run Vineeth Remanan Pillai
2019-04-26 15:03 ` Peter Zijlstra
2019-04-29 12:36 ` Julien Desfossez
2019-04-23 16:18 ` [RFC PATCH v2 17/17] sched: Debug bits Vineeth Remanan Pillai
2019-05-17 17:18 ` Aubrey Li
2019-04-23 18:02 ` [RFC PATCH v2 00/17] Core scheduling v2 Phil Auld
2019-04-23 18:45 ` Vineeth Remanan Pillai
2019-04-29 3:53 ` Aaron Lu
2019-05-06 19:39 ` Julien Desfossez
2019-05-08 2:30 ` Aaron Lu
2019-05-08 17:49 ` Julien Desfossez
2019-05-09 2:11 ` Aaron Lu
2019-05-15 21:36 ` Vineeth Remanan Pillai
2019-04-23 23:25 ` Aubrey Li
2019-04-24 11:19 ` Vineeth Remanan Pillai
2019-05-15 21:39 ` Vineeth Remanan Pillai
2019-04-24 13:13 ` Aubrey Li
2019-04-24 14:00 ` Julien Desfossez
2019-04-25 3:15 ` Aubrey Li
2019-04-25 9:55 ` Ingo Molnar
2019-04-25 14:46 ` Mel Gorman
2019-04-25 18:53 ` Ingo Molnar
2019-04-25 18:59 ` Thomas Gleixner
2019-04-25 19:34 ` Ingo Molnar
2019-04-25 21:31 ` Mel Gorman
2019-04-26 8:42 ` Ingo Molnar
2019-04-26 10:43 ` Mel Gorman
2019-04-26 18:37 ` Subhra Mazumdar
2019-04-26 19:49 ` Mel Gorman
2019-04-26 9:45 ` Ingo Molnar
2019-04-26 10:19 ` Mel Gorman
2019-04-27 9:06 ` Ingo Molnar
2019-04-26 9:51 ` Ingo Molnar
2019-04-26 14:15 ` Phil Auld
2019-04-26 2:18 ` Aubrey Li
2019-04-26 9:51 ` Ingo Molnar
2019-04-27 3:51 ` Aubrey Li
2019-04-27 9:17 ` Ingo Molnar
2019-04-27 14:04 ` Aubrey Li
2019-04-27 14:21 ` Ingo Molnar
2019-04-27 15:54 ` Aubrey Li
2019-04-28 9:33 ` Ingo Molnar
2019-04-28 10:29 ` Aubrey Li
2019-04-28 12:17 ` Ingo Molnar
2019-04-29 2:17 ` Li, Aubrey
2019-04-29 6:14 ` Ingo Molnar
2019-04-29 13:25 ` Li, Aubrey
2019-04-29 15:39 ` Phil Auld
2019-04-30 1:24 ` Aubrey Li
2019-04-29 16:00 ` Ingo Molnar
2019-04-30 1:34 ` Aubrey Li
2019-04-30 4:42 ` Ingo Molnar
2019-05-18 0:58 ` Li, Aubrey
2019-05-18 1:08 ` Li, Aubrey
2019-04-25 14:36 ` Julien Desfossez
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