From: Marcelo Tosatti <mtosatti@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>,
Frederic Weisbecker <frederic@kernel.org>
Cc: linux-kernel@vger.kernel.org, Marcelo Tosatti <mtosatti@redhat.com>
Subject: [patch 2/3] nohz: change signal tick dependency to wakeup CPUs of member tasks
Date: Thu, 28 Jan 2021 15:40:50 -0300 [thread overview]
Message-ID: <20210128184346.781151254@fuller.cnet> (raw)
In-Reply-To: 20210128184048.287626221@fuller.cnet
Rather than waking up all nohz_full CPUs on the system, only wakeup
the target CPUs of member threads of the signal.
Reduces interruptions to nohz_full CPUs.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Index: linux-2.6/kernel/time/tick-sched.c
===================================================================
--- linux-2.6.orig/kernel/time/tick-sched.c
+++ linux-2.6/kernel/time/tick-sched.c
@@ -446,7 +446,17 @@ EXPORT_SYMBOL_GPL(tick_nohz_dep_clear_ta
*/
void tick_nohz_dep_set_signal(struct signal_struct *sig, enum tick_dep_bits bit)
{
- tick_nohz_dep_set_all(&sig->tick_dep_mask, bit);
+ int prev;
+
+ prev = atomic_fetch_or(BIT(bit), &sig->tick_dep_mask);
+ if (!prev) {
+ struct task_struct *t;
+
+ rcu_read_lock();
+ __for_each_thread(sig, t)
+ tick_nohz_kick_task(t);
+ rcu_read_unlock();
+ }
}
void tick_nohz_dep_clear_signal(struct signal_struct *sig, enum tick_dep_bits bit)
next prev parent reply other threads:[~2021-01-28 18:52 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-28 18:40 [patch 0/3] nohz_full: only wakeup target CPUs when notifying new tick dependency (v4) Marcelo Tosatti
2021-01-28 18:40 ` [patch 1/3] nohz: only wakeup a single target cpu when kicking a task Marcelo Tosatti
2021-01-28 18:40 ` Marcelo Tosatti [this message]
2021-01-28 18:40 ` [patch 3/3] nohz: tick_nohz_kick_task: only IPI if remote task is running Marcelo Tosatti
2021-01-28 20:21 [patch 0/3] nohz_full: only wakeup target CPUs when notifying new tick dependency (v5) Marcelo Tosatti
2021-01-28 20:21 ` [patch 2/3] nohz: change signal tick dependency to wakeup CPUs of member tasks Marcelo Tosatti
2021-02-12 12:25 ` Frederic Weisbecker
2021-02-12 14:00 ` Marcelo Tosatti
2021-02-12 14:18 ` Frederic Weisbecker
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