diff options
| author | Marcelo Tosatti <mtosatti@redhat.com> | 2021-05-13 01:29:21 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2021-05-13 14:21:22 +0200 |
| commit | 1e4ca26d367ae71743e25068e5cd8750ef3f5f7d (patch) | |
| tree | 4d89ae90d0e287d73405c76b018a52f99321396b | |
| parent | 29721b859217b946bfc001c1644745ed4d7c26cb (diff) | |
tick/nohz: Change signal tick dependency to wake up CPUs of member tasks
Rather than waking up all nohz_full CPUs on the system, only wake up
the target CPUs of member threads of the signal.
Reduces interruptions to nohz_full CPUs.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210512232924.150322-8-frederic@kernel.org
| -rw-r--r-- | include/linux/tick.h | 8 | ||||
| -rw-r--r-- | kernel/time/posix-cpu-timers.c | 4 | ||||
| -rw-r--r-- | 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 b90ca6635ea4..acbe6722cf75 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) |