Re: [PATCH v4 02/36] hrtimer: Correct blantanly wrong comment
From: Ingo Molnar
Date: Mon Jan 15 2018 - 20:02:48 EST
* Anna-Maria Gleixner <anna-maria@xxxxxxxxxxxxx> wrote:
> From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
>
> The protection of a hrtimer which runs its callback against migration to a
> different CPU has nothing to do with hard interrupt context.
>
> The protection against migration of a hrtimer running the expiry callback
> is the pointer in the cpu_base which holds a pointer to the currently
> running timer. This pointer is evaluated in the code which potentially
> switches the timer base and makes sure it's kept on the CPU on which the
> callback is running.
>
> Reported-by: Anna-Maria Gleixner <anna-maria@xxxxxxxxxxxxx>
> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Signed-off-by: Anna-Maria Gleixner <anna-maria@xxxxxxxxxxxxx>
> ---
> kernel/time/hrtimer.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
> index 69d203d8b12d..aee49c0c58b9 100644
> --- a/kernel/time/hrtimer.c
> +++ b/kernel/time/hrtimer.c
> @@ -1195,9 +1195,9 @@ static void __run_hrtimer(struct hrtimer_cpu_base *cpu_base,
> timer->is_rel = false;
>
> /*
> - * Because we run timers from hardirq context, there is no chance
> - * they get migrated to another cpu, therefore its safe to unlock
> - * the timer base.
> + * The timer is marked as running in the cpu base, so it is
> + * protected against migration to a different CPU even if the lock
> + * is dropped.
Small, nit:
s/cpu/CPU
to keep the capitalization consistent within the same sentence.
Thanks,
Ingo