Thread (1 message) 1 message, 1 author, 2023-03-15
STALE1279d REVIEWED: 6 (6M)

1 review trailer (1 from subsystem maintainers).

[PATCH 2/9] rcu: Fix missing TICK_DEP_MASK_RCU_EXP dependency check

From: Joel Fernandes (Google) <hidden>
Date: 2023-03-15 19:45:08
Also in: lkml
Subsystem: nohz, dynticks support, posix clocks and timers, the rest, tracing · Maintainers: Anna-Maria Behnsen, Frederic Weisbecker, Ingo Molnar, Thomas Gleixner, Linus Torvalds, Steven Rostedt, Masami Hiramatsu

From: Zqiang <redacted>

This commit adds checks for the TICK_DEP_MASK_RCU_EXP bit, thus enabling
RCU expedited grace periods to actually force-enable scheduling-clock
interrupts on holdout CPUs.

Fixes: df1e849ae455 ("rcu: Enable tick for nohz_full CPUs slow to provide expedited QS")
Signed-off-by: Zqiang <redacted>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Frederic Weisbecker <redacted>
Cc: Thomas Gleixner <redacted>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Anna-Maria Behnsen <anna-maria@linutronix.de>
Acked-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Joel Fernandes (Google) <redacted>
---
 include/trace/events/timer.h | 3 ++-
 kernel/time/tick-sched.c     | 5 +++++
 2 files changed, 7 insertions(+), 1 deletion(-)
diff --git a/include/trace/events/timer.h b/include/trace/events/timer.h
index 2e713a7d9aa3..3e8619c72f77 100644
--- a/include/trace/events/timer.h
+++ b/include/trace/events/timer.h
@@ -371,7 +371,8 @@ TRACE_EVENT(itimer_expire,
 		tick_dep_name(PERF_EVENTS)		\
 		tick_dep_name(SCHED)			\
 		tick_dep_name(CLOCK_UNSTABLE)		\
-		tick_dep_name_end(RCU)
+		tick_dep_name(RCU)			\
+		tick_dep_name_end(RCU_EXP)
 
 #undef tick_dep_name
 #undef tick_dep_mask_name
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index b0e3c9205946..ba2ac1469d47 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -281,6 +281,11 @@ static bool check_tick_dependency(atomic_t *dep)
 		return true;
 	}
 
+	if (val & TICK_DEP_MASK_RCU_EXP) {
+		trace_tick_stop(0, TICK_DEP_MASK_RCU_EXP);
+		return true;
+	}
+
 	return false;
 }
 
-- 
2.40.0.rc1.284.g88254d51c5-goog
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