diff options
| author | Joel Fernandes (Google) <joel@joelfernandes.org> | 2020-08-11 13:34:28 -0400 |
|---|---|---|
| committer | Joel Fernandes <joelaf@google.com> | 2020-12-06 13:38:18 -0500 |
| commit | 81ab496aa4fb2f215f7e10edfaaccecc67eef58a (patch) | |
| tree | fcfc8214d6f63d492a0c261be3cedbeb9e1dedb1 | |
| parent | 8dc5a6402df1dd89a69967c2125caaa29202338a (diff) | |
| download | linux-81ab496aa4fb2f215f7e10edfaaccecc67eef58a.tar.gz | |
entry/idle: Enter and exit kernel protection during idle entry and exit
Notice: this object is not reachable from any branch.
Add a generic_idle_{enter,exit} helper function to enter and exit kernel
protection when entering and exiting idle, respectively.
While at it, remove a stale RCU comment.
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Tested-by: Julien Desfossez <jdesfossez@digitalocean.com>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Notice: this object is not reachable from any branch.
| -rw-r--r-- | include/linux/entry-common.h | 18 | ||||
| -rw-r--r-- | kernel/sched/idle.c | 11 |
2 files changed, 24 insertions, 5 deletions
diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h index 022e1f1141574..8f34ae625f839 100644 --- a/include/linux/entry-common.h +++ b/include/linux/entry-common.h @@ -454,4 +454,22 @@ static inline bool entry_kernel_protected(void) return IS_ENABLED(CONFIG_SCHED_CORE) && sched_core_kernel_protected() && _TIF_UNSAFE_RET != 0; } + +/** + * generic_idle_enter - General tasks to perform during idle entry. + */ +static inline void generic_idle_enter(void) +{ + /* Entering idle ends the protected kernel region. */ + sched_core_unsafe_exit(); +} + +/** + * generic_idle_exit - General tasks to perform during idle exit. + */ +static inline void generic_idle_exit(void) +{ + /* Exiting idle (re)starts the protected kernel region. */ + sched_core_unsafe_enter(); +} #endif diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c index 8bdb214eb78f7..ee4f91396c311 100644 --- a/kernel/sched/idle.c +++ b/kernel/sched/idle.c @@ -8,6 +8,7 @@ */ #include "sched.h" +#include <linux/entry-common.h> #include <trace/events/power.h> /* Linker adds these: start and end of __cpuidle functions */ @@ -54,6 +55,7 @@ __setup("hlt", cpu_idle_nopoll_setup); static noinline int __cpuidle cpu_idle_poll(void) { + generic_idle_enter(); trace_cpu_idle(0, smp_processor_id()); stop_critical_timings(); rcu_idle_enter(); @@ -66,6 +68,7 @@ static noinline int __cpuidle cpu_idle_poll(void) rcu_idle_exit(); start_critical_timings(); trace_cpu_idle(PWR_EVENT_EXIT, smp_processor_id()); + generic_idle_exit(); return 1; } @@ -156,11 +159,7 @@ static void cpuidle_idle_call(void) return; } - /* - * The RCU framework needs to be told that we are entering an idle - * section, so no more rcu read side critical sections and one more - * step to the grace period - */ + generic_idle_enter(); if (cpuidle_not_available(drv, dev)) { tick_nohz_idle_stop_tick(); @@ -225,6 +224,8 @@ exit_idle: */ if (WARN_ON_ONCE(irqs_disabled())) local_irq_enable(); + + generic_idle_exit(); } /* |