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authorLinus Torvalds <torvalds@linux-foundation.org>2020-08-03 14:31:33 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-08-03 14:31:33 -0700
commit8f0cb6660acb0d4756df880a3e60e73daa9c244e (patch)
tree9f14396bed65f82b94f7bb2425ffb2f0cbd4519a /kernel/time
parent5ece08178d6567db5ef0090b1ae7f795c3c36161 (diff)
parentc1cc4784ce6e8cceff1013709abd74bcbf7fbf24 (diff)
Merge tag 'core-rcu-2020-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull RCU updates from Ingo Molnar: - kfree_rcu updates - RCU tasks updates - Read-side scalability tests - SRCU updates - Torture-test updates - Documentation updates - Miscellaneous fixes * tag 'core-rcu-2020-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (109 commits) torture: Remove obsolete "cd $KVM" torture: Avoid duplicate specification of qemu command torture: Dump ftrace at shutdown only if requested torture: Add kvm-tranform.sh script for qemu-cmd files torture: Add more tracing crib notes to kvm.sh torture: Improve diagnostic for KCSAN-incapable compilers torture: Correctly summarize build-only runs torture: Pass --kmake-arg to all make invocations rcutorture: Check for unwatched readers torture: Abstract out console-log error detection torture: Add a stop-run capability torture: Create qemu-cmd in --buildonly runs rcu/rcutorture: Replace 0 with false torture: Add --allcpus argument to the kvm.sh script torture: Remove whitespace from identify_qemu_vcpus output rcutorture: NULL rcu_torture_current earlier in cleanup code rcutorture: Handle non-statistic bang-string error messages torture: Set configfile variable to current scenario rcutorture: Add races with task-exit processing locktorture: Use true and false to assign to bool variables ...
Diffstat (limited to 'kernel/time')
-rw-r--r--kernel/time/tick-sched.c22
1 files changed, 15 insertions, 7 deletions
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 3e2dc9b8858c..f0199a4ba1ad 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -351,16 +351,24 @@ void tick_nohz_dep_clear_cpu(int cpu, enum tick_dep_bits bit)
EXPORT_SYMBOL_GPL(tick_nohz_dep_clear_cpu);
/*
- * Set a per-task tick dependency. Posix CPU timers need this in order to elapse
- * per task timers.
+ * Set a per-task tick dependency. RCU need this. Also posix CPU timers
+ * in order to elapse per task timers.
*/
void tick_nohz_dep_set_task(struct task_struct *tsk, enum tick_dep_bits bit)
{
- /*
- * We could optimize this with just kicking the target running the task
- * if that noise matters for nohz full users.
- */
- tick_nohz_dep_set_all(&tsk->tick_dep_mask, bit);
+ if (!atomic_fetch_or(BIT(bit), &tsk->tick_dep_mask)) {
+ if (tsk == current) {
+ preempt_disable();
+ tick_nohz_full_kick();
+ preempt_enable();
+ } else {
+ /*
+ * Some future tick_nohz_full_kick_task()
+ * should optimize this.
+ */
+ tick_nohz_full_kick_all();
+ }
+ }
}
EXPORT_SYMBOL_GPL(tick_nohz_dep_set_task);