From: Patrick Bellasi <patrick.bellasi@arm.com>
To: linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
linux-api@vger.kernel.org
Cc: Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>, Tejun Heo <tj@kernel.org>,
"Rafael J . Wysocki" <rafael.j.wysocki@intel.com>,
Vincent Guittot <vincent.guittot@linaro.org>,
Viresh Kumar <viresh.kumar@linaro.org>,
Paul Turner <pjt@google.com>,
Quentin Perret <quentin.perret@arm.com>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Morten Rasmussen <morten.rasmussen@arm.com>,
Juri Lelli <juri.lelli@redhat.com>, Todd Kjos <tkjos@google.com>,
Joel Fernandes <joelaf@google.com>,
Steve Muckle <smuckle@google.com>,
Suren Baghdasaryan <surenb@google.com>
Subject: [PATCH v6 05/16] sched/core: uclamp: Update CPU's refcount on clamp changes
Date: Tue, 15 Jan 2019 10:15:02 +0000 [thread overview]
Message-ID: <20190115101513.2822-6-patrick.bellasi@arm.com> (raw)
In-Reply-To: <20190115101513.2822-1-patrick.bellasi@arm.com>
Utilization clamp values enforced on a CPU by a task can be updated, for
example via a sched_setattr() syscall, while a task is RUNNABLE on that
CPU. A clamp value change always implies a clamp bucket refcount update
to ensure the new constraints are enforced.
Hook into uclamp_bucket_get() to trigger a CPU refcount syncup, via
uclamp_cpu_{inc,dec}_id(), whenever a task is RUNNABLE.
Signed-off-by: Patrick Bellasi <patrick.bellasi@arm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
---
Changes in v6:
Other:
- wholesale s/group/bucket/
- wholesale s/_{get,put}/_{inc,dec}/ to match refcount APIs
- small documentation updates
---
kernel/sched/core.c | 48 +++++++++++++++++++++++++++++++++++++++------
1 file changed, 42 insertions(+), 6 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 190137cd7b3b..67f059ee0a05 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -884,6 +884,38 @@ static inline void uclamp_cpu_dec(struct rq *rq, struct task_struct *p)
uclamp_cpu_dec_id(p, rq, clamp_id);
}
+static inline void
+uclamp_task_update_active(struct task_struct *p, unsigned int clamp_id)
+{
+ struct rq_flags rf;
+ struct rq *rq;
+
+ /*
+ * Lock the task and the CPU where the task is (or was) queued.
+ *
+ * We might lock the (previous) rq of a !RUNNABLE task, but that's the
+ * price to pay to safely serialize util_{min,max} updates with
+ * enqueues, dequeues and migration operations.
+ * This is the same locking schema used by __set_cpus_allowed_ptr().
+ */
+ rq = task_rq_lock(p, &rf);
+
+ /*
+ * Setting the clamp bucket is serialized by task_rq_lock().
+ * If the task is not yet RUNNABLE and its task_struct is not
+ * affecting a valid clamp bucket, the next time it's enqueued,
+ * it will already see the updated clamp bucket value.
+ */
+ if (!p->uclamp[clamp_id].active)
+ goto done;
+
+ uclamp_cpu_dec_id(p, rq, clamp_id);
+ uclamp_cpu_inc_id(p, rq, clamp_id);
+
+done:
+ task_rq_unlock(rq, p, &rf);
+}
+
static void uclamp_bucket_dec(unsigned int clamp_id, unsigned int bucket_id)
{
union uclamp_map *uc_maps = &uclamp_maps[clamp_id][0];
@@ -907,8 +939,8 @@ static void uclamp_bucket_dec(unsigned int clamp_id, unsigned int bucket_id)
&uc_map_old.data, uc_map_new.data));
}
-static void uclamp_bucket_inc(struct uclamp_se *uc_se, unsigned int clamp_id,
- unsigned int clamp_value)
+static void uclamp_bucket_inc(struct task_struct *p, struct uclamp_se *uc_se,
+ unsigned int clamp_id, unsigned int clamp_value)
{
union uclamp_map *uc_maps = &uclamp_maps[clamp_id][0];
unsigned int prev_bucket_id = uc_se->bucket_id;
@@ -979,6 +1011,9 @@ static void uclamp_bucket_inc(struct uclamp_se *uc_se, unsigned int clamp_id,
uc_se->value = clamp_value;
uc_se->bucket_id = bucket_id;
+ if (p)
+ uclamp_task_update_active(p, clamp_id);
+
if (uc_se->mapped)
uclamp_bucket_dec(clamp_id, prev_bucket_id);
@@ -1008,11 +1043,11 @@ static int __setscheduler_uclamp(struct task_struct *p,
mutex_lock(&uclamp_mutex);
if (attr->sched_flags & SCHED_FLAG_UTIL_CLAMP_MIN) {
- uclamp_bucket_inc(&p->uclamp[UCLAMP_MIN],
+ uclamp_bucket_inc(p, &p->uclamp[UCLAMP_MIN],
UCLAMP_MIN, lower_bound);
}
if (attr->sched_flags & SCHED_FLAG_UTIL_CLAMP_MAX) {
- uclamp_bucket_inc(&p->uclamp[UCLAMP_MAX],
+ uclamp_bucket_inc(p, &p->uclamp[UCLAMP_MAX],
UCLAMP_MAX, upper_bound);
}
mutex_unlock(&uclamp_mutex);
@@ -1049,7 +1084,8 @@ static void uclamp_fork(struct task_struct *p, bool reset)
p->uclamp[clamp_id].mapped = false;
p->uclamp[clamp_id].active = false;
- uclamp_bucket_inc(&p->uclamp[clamp_id], clamp_id, clamp_value);
+ uclamp_bucket_inc(NULL, &p->uclamp[clamp_id],
+ clamp_id, clamp_value);
}
}
@@ -1069,7 +1105,7 @@ static void __init init_uclamp(void)
memset(uclamp_maps, 0, sizeof(uclamp_maps));
for (clamp_id = 0; clamp_id < UCLAMP_CNT; ++clamp_id) {
uc_se = &init_task.uclamp[clamp_id];
- uclamp_bucket_inc(uc_se, clamp_id, uclamp_none(clamp_id));
+ uclamp_bucket_inc(NULL, uc_se, clamp_id, uclamp_none(clamp_id));
}
}
--
2.19.2
next prev parent reply other threads:[~2019-01-15 10:15 UTC|newest]
Thread overview: 89+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-15 10:14 [PATCH v6 00/16] Add utilization clamping support Patrick Bellasi
2019-01-15 10:14 ` [PATCH v6 01/16] sched/core: Allow sched_setattr() to use the current policy Patrick Bellasi
2019-01-25 13:56 ` Alessio Balsini
2019-01-15 10:14 ` [PATCH v6 02/16] sched/core: uclamp: Extend sched_setattr() to support utilization clamping Patrick Bellasi
2019-01-15 10:15 ` [PATCH v6 03/16] sched/core: uclamp: Map TASK's clamp values into CPU's clamp buckets Patrick Bellasi
2019-01-21 10:15 ` Peter Zijlstra
2019-01-21 12:27 ` Patrick Bellasi
2019-01-21 12:51 ` Peter Zijlstra
2019-01-21 15:05 ` Peter Zijlstra
2019-01-21 15:34 ` Patrick Bellasi
2019-01-15 10:15 ` [PATCH v6 04/16] sched/core: uclamp: Add CPU's clamp buckets refcounting Patrick Bellasi
2019-01-21 14:59 ` Peter Zijlstra
2019-01-21 15:23 ` Patrick Bellasi
2019-01-21 16:12 ` Peter Zijlstra
2019-01-21 16:33 ` Patrick Bellasi
2019-01-22 9:45 ` Peter Zijlstra
2019-01-22 10:31 ` Patrick Bellasi
2019-01-21 15:17 ` Peter Zijlstra
2019-01-21 15:54 ` Patrick Bellasi
2019-01-22 10:03 ` Peter Zijlstra
2019-01-22 10:53 ` Patrick Bellasi
2019-01-15 10:15 ` Patrick Bellasi [this message]
2019-01-21 15:33 ` [PATCH v6 05/16] sched/core: uclamp: Update CPU's refcount on clamp changes Peter Zijlstra
2019-01-21 15:44 ` Patrick Bellasi
2019-01-22 9:37 ` Peter Zijlstra
2019-01-22 10:43 ` Patrick Bellasi
2019-01-22 13:28 ` Peter Zijlstra
2019-01-22 14:01 ` Patrick Bellasi
2019-01-22 14:57 ` Peter Zijlstra
2019-01-22 15:33 ` Patrick Bellasi
2019-01-23 9:16 ` Peter Zijlstra
2019-01-23 14:14 ` Patrick Bellasi
2019-01-23 18:59 ` Peter Zijlstra
2019-01-24 11:21 ` Patrick Bellasi
2019-01-24 12:38 ` Peter Zijlstra
2019-01-15 10:15 ` [PATCH v6 06/16] sched/core: uclamp: Enforce last task UCLAMP_MAX Patrick Bellasi
2019-01-15 10:15 ` [PATCH v6 07/16] sched/core: uclamp: Add system default clamps Patrick Bellasi
2019-01-22 13:56 ` Peter Zijlstra
2019-01-22 14:43 ` Patrick Bellasi
2019-01-22 15:13 ` Peter Zijlstra
2019-01-22 15:41 ` Patrick Bellasi
2019-01-23 9:22 ` Peter Zijlstra
2019-01-23 14:19 ` Patrick Bellasi
2019-01-23 19:10 ` Peter Zijlstra
2019-01-15 10:15 ` [PATCH v6 08/16] sched/cpufreq: uclamp: Add utilization clamping for FAIR tasks Patrick Bellasi
2019-01-22 10:37 ` Rafael J. Wysocki
2019-01-22 11:02 ` Patrick Bellasi
2019-01-22 11:04 ` Rafael J. Wysocki
2019-01-22 11:27 ` Patrick Bellasi
2019-01-22 15:21 ` Peter Zijlstra
2019-01-22 15:45 ` Patrick Bellasi
2019-01-22 17:13 ` Peter Zijlstra
2019-01-22 18:18 ` Patrick Bellasi
2019-01-23 9:52 ` Peter Zijlstra
2019-01-23 14:24 ` Patrick Bellasi
2019-01-15 10:15 ` [PATCH v6 09/16] sched/cpufreq: uclamp: Add utilization clamping for RT tasks Patrick Bellasi
2019-01-22 12:30 ` Quentin Perret
2019-01-22 12:37 ` Patrick Bellasi
2019-01-23 10:28 ` Peter Zijlstra
2019-01-23 14:33 ` Patrick Bellasi
2019-01-23 10:49 ` Peter Zijlstra
2019-01-23 14:40 ` Patrick Bellasi
2019-01-23 20:11 ` Peter Zijlstra
2019-01-24 12:30 ` Patrick Bellasi
2019-01-24 12:38 ` Patrick Bellasi
2019-01-24 15:12 ` Peter Zijlstra
2019-01-24 16:00 ` Patrick Bellasi
2019-01-24 15:31 ` Peter Zijlstra
2019-01-24 16:14 ` Patrick Bellasi
2019-01-24 15:33 ` Peter Zijlstra
2019-01-24 15:15 ` Peter Zijlstra
2019-01-24 16:05 ` Patrick Bellasi
2019-01-15 10:15 ` [PATCH v6 10/16] sched/core: Add uclamp_util_with() Patrick Bellasi
2019-01-23 13:33 ` Peter Zijlstra
2019-01-23 14:51 ` Patrick Bellasi
2019-01-23 19:22 ` Peter Zijlstra
2019-01-15 10:15 ` [PATCH v6 11/16] sched/fair: Add uclamp support to energy_compute() Patrick Bellasi
2019-01-22 12:13 ` Quentin Perret
2019-01-22 12:45 ` Patrick Bellasi
2019-01-22 13:29 ` Quentin Perret
2019-01-22 14:26 ` Patrick Bellasi
2019-01-22 14:39 ` Quentin Perret
2019-01-22 15:01 ` Patrick Bellasi
2019-01-22 15:14 ` Quentin Perret
2019-01-15 10:15 ` [PATCH v6 12/16] sched/core: uclamp: Extend CPU's cgroup controller Patrick Bellasi
2019-01-15 10:15 ` [PATCH v6 13/16] sched/core: uclamp: Propagate parent clamps Patrick Bellasi
2019-01-15 10:15 ` [PATCH v6 14/16] sched/core: uclamp: Map TG's clamp values into CPU's clamp buckets Patrick Bellasi
2019-01-15 10:15 ` [PATCH v6 15/16] sched/core: uclamp: Use TG's clamps to restrict TASK's clamps Patrick Bellasi
2019-01-15 10:15 ` [PATCH v6 16/16] sched/core: uclamp: Update CPU's refcount on TG's clamp changes Patrick Bellasi
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