Re: [PATCH v3 2/2] sched/cache: Drive cache task tick from execution context

[Chen, Yu C]

On 9/4/2026 4:52 PM, Hui Su wrote:
> Cache-aware scheduling accounts CPU runtime to the mm of the task
> actually executing. update_se() passes the execution task to
> account_mm_sched() for this purpose.
>
> With proxy execution, however, sched_tick() invokes task_tick() for the
> scheduling context in rq->donor. task_tick_cache() is currently called
> from task_tick_fair(), so it is skipped when a fair task executes on
> behalf of an RT or deadline donor.
>
> In that case account_mm_sched() continues to advance runtime accounting
> for rq->curr, while task_tick_cache() does not advance the corresponding
> mm scan epoch. Once the epoch becomes stale, account_mm_sched() can
> invalidate the mm's preferred LLC.
>
> Move cache tick handling into sched_tick_exec_ctx(), alongside NUMA tick
> handling, and run it when the execution context is a fair task. Use the
> same helper from sched_tick() and sched_tick_remote() so both tick paths
> handle the execution context consistently.
>
> Keep the remaining task_tick_fair() bookkeeping with its task argument,
> since misfit, overutilized, and core scheduling state belong to the
> scheduling context.
>
> Fixes: df0d98475954 ("sched/cache: Introduce infrastructure for cache-aware load balancing")
> Suggested-by: Tim Chen <tim.c.chen@xxxxxxxxxxxxxxx>
> Signed-off-by: Hui Su <sh_def@xxxxxxx>

Thanks for the fix,

Reviewed-by: Chen Yu <yu.c.chen@xxxxxxxxx>

thanks,
Chenyu