android_kernel_motorola_sm6375/kernel/rcu
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Filename Latest commit message Latest commit date
Ankur Arora be6ab68820 rcu: handle quiescent states for PREEMPT_RCU=n, PREEMPT_COUNT=y
[ Upstream commit 83b28cfe796464ebbde1cf7916c126da6d572685 ]

With PREEMPT_RCU=n, cond_resched() provides urgently needed quiescent
states for read-side critical sections via rcu_all_qs().
One reason why this was needed: lacking preempt-count, the tick
handler has no way of knowing whether it is executing in a
read-side critical section or not.

With (PREEMPT_LAZY=y, PREEMPT_DYNAMIC=n), we get (PREEMPT_COUNT=y,
PREEMPT_RCU=n). In this configuration cond_resched() is a stub and
does not provide quiescent states via rcu_all_qs().
(PREEMPT_RCU=y provides this information via rcu_read_unlock() and
its nesting counter.)

So, use the availability of preempt_count() to report quiescent states
in rcu_flavor_sched_clock_irq().

Suggested-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Ankur Arora <ankur.a.arora@oracle.com>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-06-04 14:32:34 +02:00
..
Kconfig
Kconfig.debug
Makefile
rcu.h srcu: Fix broken node geometry after early ssp init 2021-07-20 16:10:41 +02:00
rcu_segcblist.c
rcu_segcblist.h
rcuperf.c
rcutorture.c rcutorture: Fix rcu_torture_one_read() pipe_count overflow comment 2024-07-05 09:08:20 +02:00
srcutiny.c
srcutree.c srcu: Fix broken node geometry after early ssp init 2021-07-20 16:10:41 +02:00
sync.c
tiny.c
tree.c rcu: Fix __this_cpu_read() lockdep warning in rcu_force_quiescent_state() 2023-01-18 11:41:33 +01:00
tree.h
tree_exp.h rcu: Suppress smp_processor_id() complaint in synchronize_rcu_expedited_wait() 2023-03-11 16:43:54 +01:00
tree_plugin.h rcu: handle quiescent states for PREEMPT_RCU=n, PREEMPT_COUNT=y 2025-06-04 14:32:34 +02:00
tree_stall.h rcu/tree: Handle VM stoppage in stall detection 2021-09-15 09:47:26 +02:00
update.c