Re: [PATCH 4/6] tick/nohz: Move nohz_full related fields out of hot task struct's places

[Valentin Schneider]

On 03/07/25 16:07, Frederic Weisbecker wrote:
> nohz_full is a feature that only fits into rare and very corner cases.
> Yet distros enable it by default and therefore the related fields are
> always reserved in the task struct.
>
> Those task fields are stored in the middle of cacheline hot places such
> as cputime accounting and context switch counting, which doesn't make
> any sense for a feature that is disabled most of the time.
>
> Move the nohz_full storage to colder places.
>
> Signed-off-by: Frederic Weisbecker <frederic@xxxxxxxxxx>

task_struct is still a bloody maze to me, but AFAICT there's *at least one*
full non-optional cacheline - the signal handling faff - between cputime
accounting and this new location, so:

Reviewed-by: Valentin Schneider <vschneid@xxxxxxxxxx>