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| author | Joel Fernandes (Google) <joel@joelfernandes.org> | 2023-01-24 17:31:26 +0000 |
|---|---|---|
| committer | Joel Fernandes (Google) <joel@joelfernandes.org> | 2023-04-05 13:47:43 +0000 |
| commit | 58d7668242647e661a20efe065519abd6454287e (patch) | |
| tree | 1647cff9cfb8120c555f996ce478daa469821812 /kernel/time | |
| parent | 424d7b3ea99d13d7787432df8a6d2327fc6fda3c (diff) | |
| download | linux-58d7668242647e661a20efe065519abd6454287e.tar.gz | |
tick/nohz: Fix cpu_is_hotpluggable() by checking with nohz subsystem
For CONFIG_NO_HZ_FULL systems, the tick_do_timer_cpu cannot be offlined.
However, cpu_is_hotpluggable() still returns true for those CPUs. This causes
torture tests that do offlining to end up trying to offline this CPU causing
test failures. Such failure happens on all architectures.
Fix the repeated error messages thrown by this (even if the hotplug errors are
harmless) by asking the opinion of the nohz subsystem on whether the CPU can be
hotplugged.
[ Apply Frederic Weisbecker feedback on refactoring tick_nohz_cpu_down(). ]
For drivers/base/ portion:
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Frederic Weisbecker <frederic@kernel.org>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Zhouyi Zhou <zhouzhouyi@gmail.com>
Cc: Will Deacon <will@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: rcu <rcu@vger.kernel.org>
Cc: stable@vger.kernel.org
Fixes: 2987557f52b9 ("driver-core/cpu: Expose hotpluggability to the rest of the kernel")
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Diffstat (limited to 'kernel/time')
| -rw-r--r-- | kernel/time/tick-sched.c | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index b0e3c9205946f..68d81a4283c89 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -527,7 +527,7 @@ void __init tick_nohz_full_setup(cpumask_var_t cpumask) tick_nohz_full_running = true; } -static int tick_nohz_cpu_down(unsigned int cpu) +bool tick_nohz_cpu_hotpluggable(unsigned int cpu) { /* * The tick_do_timer_cpu CPU handles housekeeping duty (unbound @@ -535,8 +535,13 @@ static int tick_nohz_cpu_down(unsigned int cpu) * CPUs. It must remain online when nohz full is enabled. */ if (tick_nohz_full_running && tick_do_timer_cpu == cpu) - return -EBUSY; - return 0; + return false; + return true; +} + +static int tick_nohz_cpu_down(unsigned int cpu) +{ + return tick_nohz_cpu_hotpluggable(cpu) ? 0 : -EBUSY; } void __init tick_nohz_init(void) |