From 1e4ca26d367ae71743e25068e5cd8750ef3f5f7d Mon Sep 17 00:00:00 2001 From: Marcelo Tosatti Date: Thu, 13 May 2021 01:29:21 +0200 Subject: 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 Signed-off-by: Frederic Weisbecker Signed-off-by: Ingo Molnar Acked-by: Peter Zijlstra Link: https://lore.kernel.org/r/20210512232924.150322-8-frederic@kernel.org --- kernel/time/tick-sched.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) (limited to 'kernel/time/tick-sched.c') 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) -- cgit v1.2.3