From: Frederic Weisbecker <frederic@kernel.org> To: Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@kernel.org> Cc: LKML <linux-kernel@vger.kernel.org>, Marcelo Tosatti <mtosatti@redhat.com>, "Rafael J . Wysocki" <rafael.j.wysocki@intel.com>, Peter Zijlstra <peterz@infradead.org>, Yunfeng Ye <yeyunfeng@huawei.com>, Frederic Weisbecker <frederic@kernel.org> Subject: [PATCH 07/10] tick/nohz: Change signal tick dependency to wakeup CPUs of member tasks Date: Thu, 13 May 2021 01:29:21 +0200 [thread overview] Message-ID: <20210512232924.150322-8-frederic@kernel.org> (raw) In-Reply-To: <20210512232924.150322-1-frederic@kernel.org> From: Marcelo Tosatti <mtosatti@redhat.com> 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. Acked-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Cc: Yunfeng Ye <yeyunfeng@huawei.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> --- include/linux/tick.h | 8 ++++---- kernel/time/posix-cpu-timers.c | 4 ++-- kernel/time/tick-sched.c | 15 +++++++++++++-- 3 files changed, 19 insertions(+), 8 deletions(-) diff --git a/include/linux/tick.h b/include/linux/tick.h index 2258984a0e8a..0bb80a7f05b9 100644 --- a/include/linux/tick.h +++ b/include/linux/tick.h @@ -211,7 +211,7 @@ extern void tick_nohz_dep_set_task(struct task_struct *tsk, enum tick_dep_bits bit); extern void tick_nohz_dep_clear_task(struct task_struct *tsk, enum tick_dep_bits bit); -extern void tick_nohz_dep_set_signal(struct signal_struct *signal, +extern void tick_nohz_dep_set_signal(struct task_struct *tsk, enum tick_dep_bits bit); extern void tick_nohz_dep_clear_signal(struct signal_struct *signal, enum tick_dep_bits bit); @@ -256,11 +256,11 @@ static inline void tick_dep_clear_task(struct task_struct *tsk, if (tick_nohz_full_enabled()) tick_nohz_dep_clear_task(tsk, bit); } -static inline void tick_dep_set_signal(struct signal_struct *signal, +static inline void tick_dep_set_signal(struct task_struct *tsk, enum tick_dep_bits bit) { if (tick_nohz_full_enabled()) - tick_nohz_dep_set_signal(signal, bit); + tick_nohz_dep_set_signal(tsk, bit); } static inline void tick_dep_clear_signal(struct signal_struct *signal, enum tick_dep_bits bit) @@ -288,7 +288,7 @@ static inline void tick_dep_set_task(struct task_struct *tsk, enum tick_dep_bits bit) { } static inline void tick_dep_clear_task(struct task_struct *tsk, enum tick_dep_bits bit) { } -static inline void tick_dep_set_signal(struct signal_struct *signal, +static inline void tick_dep_set_signal(struct task_struct *tsk, enum tick_dep_bits bit) { } static inline void tick_dep_clear_signal(struct signal_struct *signal, enum tick_dep_bits bit) { } diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c index 3bb96a8b49c9..29a5e54e6e10 100644 --- a/kernel/time/posix-cpu-timers.c +++ b/kernel/time/posix-cpu-timers.c @@ -523,7 +523,7 @@ static void arm_timer(struct k_itimer *timer, struct task_struct *p) if (CPUCLOCK_PERTHREAD(timer->it_clock)) tick_dep_set_task(p, TICK_DEP_BIT_POSIX_TIMER); else - tick_dep_set_signal(p->signal, TICK_DEP_BIT_POSIX_TIMER); + tick_dep_set_signal(p, TICK_DEP_BIT_POSIX_TIMER); } /* @@ -1358,7 +1358,7 @@ void set_process_cpu_timer(struct task_struct *tsk, unsigned int clkid, if (*newval < *nextevt) *nextevt = *newval; - tick_dep_set_signal(tsk->signal, TICK_DEP_BIT_POSIX_TIMER); + tick_dep_set_signal(tsk, TICK_DEP_BIT_POSIX_TIMER); } static int do_cpu_nanosleep(const clockid_t which_clock, int flags, diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index 1991adf5a922..800719ea4045 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -444,9 +444,20 @@ EXPORT_SYMBOL_GPL(tick_nohz_dep_clear_task); * Set a per-taskgroup tick dependency. Posix CPU timers need this in order to elapse * per process timers. */ -void tick_nohz_dep_set_signal(struct signal_struct *sig, enum tick_dep_bits bit) +void tick_nohz_dep_set_signal(struct task_struct *tsk, + enum tick_dep_bits bit) { - tick_nohz_dep_set_all(&sig->tick_dep_mask, bit); + int prev; + struct signal_struct *sig = tsk->signal; + + prev = atomic_fetch_or(BIT(bit), &sig->tick_dep_mask); + if (!prev) { + struct task_struct *t; + + lockdep_assert_held(&tsk->sighand->siglock); + __for_each_thread(sig, t) + tick_nohz_kick_task(t); + } } void tick_nohz_dep_clear_signal(struct signal_struct *sig, enum tick_dep_bits bit) -- 2.25.1
next prev parent reply other threads:[~2021-05-12 23:43 UTC|newest] Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-05-12 23:29 [GIT PULL] tick/nohz updates v3 Frederic Weisbecker 2021-05-12 23:29 ` [PATCH 01/10] tick/nohz: Evaluate the CPU expression after the static key Frederic Weisbecker 2021-05-13 13:17 ` [tip: timers/nohz] " tip-bot2 for Peter Zijlstra 2021-05-12 23:29 ` [PATCH 02/10] tick/nohz: Conditionally restart tick on idle exit Frederic Weisbecker 2021-05-13 13:17 ` [tip: timers/nohz] " tip-bot2 for Yunfeng Ye 2021-05-12 23:29 ` [PATCH 03/10] tick/nohz: Remove superflous check for CONFIG_VIRT_CPU_ACCOUNTING_NATIVE Frederic Weisbecker 2021-05-13 13:17 ` [tip: timers/nohz] " tip-bot2 for Frederic Weisbecker 2021-05-12 23:29 ` [PATCH 04/10] tick/nohz: Update idle_exittime on actual idle exit Frederic Weisbecker 2021-05-13 13:17 ` [tip: timers/nohz] " tip-bot2 for Yunfeng Ye 2021-05-12 23:29 ` [PATCH 05/10] tick/nohz: Update nohz_full Kconfig help Frederic Weisbecker 2021-05-13 13:17 ` [tip: timers/nohz] " tip-bot2 for Frederic Weisbecker 2021-05-12 23:29 ` [PATCH 06/10] tick/nohz: Only wakeup a single target cpu when kicking a task Frederic Weisbecker 2021-05-13 13:17 ` [tip: timers/nohz] tick/nohz: Only wake up " tip-bot2 for Frederic Weisbecker 2021-05-12 23:29 ` Frederic Weisbecker [this message] 2021-05-13 13:17 ` [tip: timers/nohz] tick/nohz: Change signal tick dependency to wake up CPUs of member tasks tip-bot2 for Marcelo Tosatti 2021-05-12 23:29 ` [PATCH 08/10] tick/nohz: Kick only _queued_ task whose tick dependency is updated Frederic Weisbecker 2021-05-13 13:17 ` [tip: timers/nohz] " tip-bot2 for Marcelo Tosatti 2021-05-12 23:29 ` [PATCH 09/10] tick/nohz: Call tick_nohz_task_switch() with interrupts disabled Frederic Weisbecker 2021-05-13 13:17 ` [tip: timers/nohz] " tip-bot2 for Peter Zijlstra 2021-05-12 23:29 ` [PATCH 10/10] MAINTAINERS: Add myself as context tracking maintainer Frederic Weisbecker 2021-05-19 9:21 ` [tip: timers/nohz] " tip-bot2 for Frederic Weisbecker 2021-05-13 12:23 ` [GIT PULL] tick/nohz updates v3 Ingo Molnar
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