Messages in this thread Patch in this message | | | Date | Wed, 07 Oct 2020 15:01:53 -0300 | From | Marcelo Tosatti <> | Subject | [patch 2/2] nohz: change signal tick dependency to wakeup CPUs of member tasks |
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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 @@ -398,7 +398,15 @@ 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) { + 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)
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