From: Frederic Weisbecker <frederic@kernel.org>
To: Ingo Molnar <mingo@kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
Frederic Weisbecker <frederic@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Chris Metcalf <cmetcalf@mellanox.com>,
Thomas Gleixner <tglx@linutronix.de>,
Luiz Capitulino <lcapitulino@redhat.com>,
Christoph Lameter <cl@linux.com>,
"Paul E . McKenney" <paulmck@linux.vnet.ibm.com>,
Wanpeng Li <kernellwp@gmail.com>, Mike Galbraith <efault@gmx.de>,
Rik van Riel <riel@redhat.com>
Subject: [PATCH 5/6] sched/nohz: Remove the 1 Hz tick code
Date: Fri, 19 Jan 2018 01:02:19 +0100 [thread overview]
Message-ID: <1516320140-13189-6-git-send-email-frederic@kernel.org> (raw)
In-Reply-To: <1516320140-13189-1-git-send-email-frederic@kernel.org>
Now that the 1Hz tick is offloaded to workqueues, we can safely remove
the residual code that used to handle it locally.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wanpeng Li <kernellwp@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
---
include/linux/sched/nohz.h | 4 ----
kernel/sched/core.c | 29 -----------------------------
kernel/sched/idle_task.c | 1 -
kernel/sched/sched.h | 11 +----------
kernel/time/tick-sched.c | 6 ------
5 files changed, 1 insertion(+), 50 deletions(-)
diff --git a/include/linux/sched/nohz.h b/include/linux/sched/nohz.h
index 3d3a97d..0942172 100644
--- a/include/linux/sched/nohz.h
+++ b/include/linux/sched/nohz.h
@@ -37,8 +37,4 @@ extern void wake_up_nohz_cpu(int cpu);
static inline void wake_up_nohz_cpu(int cpu) { }
#endif
-#ifdef CONFIG_NO_HZ_FULL
-extern u64 scheduler_tick_max_deferment(void);
-#endif
-
#endif /* _LINUX_SCHED_NOHZ_H */
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index c79500c..cbc3001 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3033,35 +3033,9 @@ void scheduler_tick(void)
rq->idle_balance = idle_cpu(cpu);
trigger_load_balance(rq);
#endif
- rq_last_tick_reset(rq);
}
#ifdef CONFIG_NO_HZ_FULL
-/**
- * scheduler_tick_max_deferment
- *
- * Keep at least one tick per second when a single
- * active task is running because the scheduler doesn't
- * yet completely support full dynticks environment.
- *
- * This makes sure that uptime, CFS vruntime, load
- * balancing, etc... continue to move forward, even
- * with a very low granularity.
- *
- * Return: Maximum deferment in nanoseconds.
- */
-u64 scheduler_tick_max_deferment(void)
-{
- struct rq *rq = this_rq();
- unsigned long next, now = READ_ONCE(jiffies);
-
- next = rq->last_sched_tick + HZ;
-
- if (time_before_eq(next, now))
- return 0;
-
- return jiffies_to_nsecs(next - now);
-}
struct tick_work {
int cpu;
@@ -6028,9 +6002,6 @@ void __init sched_init(void)
rq->last_load_update_tick = jiffies;
rq->nohz_flags = 0;
#endif
-#ifdef CONFIG_NO_HZ_FULL
- rq->last_sched_tick = 0;
-#endif
#endif /* CONFIG_SMP */
hrtick_rq_init(rq);
atomic_set(&rq->nr_iowait, 0);
diff --git a/kernel/sched/idle_task.c b/kernel/sched/idle_task.c
index d518664..a64fc92 100644
--- a/kernel/sched/idle_task.c
+++ b/kernel/sched/idle_task.c
@@ -48,7 +48,6 @@ dequeue_task_idle(struct rq *rq, struct task_struct *p, int flags)
static void put_prev_task_idle(struct rq *rq, struct task_struct *prev)
{
- rq_last_tick_reset(rq);
}
static void task_tick_idle(struct rq *rq, struct task_struct *curr, int queued)
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 5a3b82c..9a25047 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -699,9 +699,7 @@ struct rq {
#endif /* CONFIG_SMP */
unsigned long nohz_flags;
#endif /* CONFIG_NO_HZ_COMMON */
-#ifdef CONFIG_NO_HZ_FULL
- unsigned long last_sched_tick;
-#endif
+
/* capture load from *all* tasks on this cpu: */
struct load_weight load;
unsigned long nr_load_updates;
@@ -1639,13 +1637,6 @@ static inline void sub_nr_running(struct rq *rq, unsigned count)
sched_update_tick_dependency(rq);
}
-static inline void rq_last_tick_reset(struct rq *rq)
-{
-#ifdef CONFIG_NO_HZ_FULL
- rq->last_sched_tick = jiffies;
-#endif
-}
-
extern void update_rq_clock(struct rq *rq);
extern void activate_task(struct rq *rq, struct task_struct *p, int flags);
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 97c4317..03ebe89 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -748,12 +748,6 @@ static ktime_t tick_nohz_stop_sched_tick(struct tick_sched *ts,
delta = KTIME_MAX;
}
-#ifdef CONFIG_NO_HZ_FULL
- /* Limit the tick delta to the maximum scheduler deferment */
- if (!ts->inidle)
- delta = min(delta, scheduler_tick_max_deferment());
-#endif
-
/* Calculate the next expiry time */
if (delta < (KTIME_MAX - basemono))
expires = basemono + delta;
--
2.7.4
next prev parent reply other threads:[~2018-01-19 0:03 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-19 0:02 [GIT PULL] isolation: 1Hz residual tick offloading v4 Frederic Weisbecker
2018-01-19 0:02 ` [PATCH 1/6] sched: Rename init_rq_hrtick to hrtick_rq_init Frederic Weisbecker
2018-01-19 0:02 ` [PATCH 2/6] nohz: Allow to check if remote CPU tick is stopped Frederic Weisbecker
2018-01-19 0:02 ` [PATCH 3/6] sched/isolation: Isolate workqueues when "nohz_full=" is set Frederic Weisbecker
2018-01-19 0:02 ` [PATCH 4/6] sched/isolation: Residual 1Hz scheduler tick offload Frederic Weisbecker
2018-01-29 15:38 ` Peter Zijlstra
2018-01-29 16:48 ` Frederic Weisbecker
2018-01-29 17:20 ` Peter Zijlstra
2018-01-29 15:39 ` Peter Zijlstra
2018-01-19 0:02 ` Frederic Weisbecker [this message]
2018-01-19 0:02 ` [PATCH 6/6] sched/isolation: Tick offload documentation Frederic Weisbecker
2018-01-24 15:46 ` [GIT PULL] isolation: 1Hz residual tick offloading v4 Luiz Capitulino
2018-01-29 1:10 ` Frederic Weisbecker
2018-01-29 15:33 ` Luiz Capitulino
2018-01-29 15:54 ` Peter Zijlstra
2018-01-29 16:27 ` Luiz Capitulino
2018-01-29 15:47 ` Peter Zijlstra
2018-05-22 19:10 ` Yauheni Kaliuta
2018-05-25 2:56 ` Frederic Weisbecker
2018-05-25 12:51 ` Luiz Capitulino
2018-01-29 1:18 ` (Ping?) " Frederic Weisbecker
2018-02-08 17:59 [PATCH 0/6] isolation: 1Hz residual tick offloading v5 Frederic Weisbecker
2018-02-08 17:59 ` [PATCH 5/6] sched/nohz: Remove the 1 Hz tick code Frederic Weisbecker
2018-02-15 0:48 [PATCH 0/6] isolation: 1Hz residual tick offloading v6 Frederic Weisbecker
2018-02-15 0:48 ` [PATCH 5/6] sched/nohz: Remove the 1 Hz tick code Frederic Weisbecker
2018-02-17 10:51 ` Thomas Gleixner
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