Re: [PATCH v5 4/5] cgroup: helper for checking rstat participation of css

[Yosry Ahmed <yosry.ahmed@linux.dev>]

On Fri, May 02, 2025 at 05:12:21PM -0700, JP Kobryn wrote:
> There are a few places where a conditional check is performed to validate a
> given css on its rstat participation. This new helper tries to make the
> code more readable where this check is performed.
> 
> Signed-off-by: JP Kobryn <inwardvessel@gmail.com>
> ---
>  kernel/cgroup/rstat.c | 17 ++++++++++++++---
>  1 file changed, 14 insertions(+), 3 deletions(-)
> 
> diff --git a/kernel/cgroup/rstat.c b/kernel/cgroup/rstat.c
> index e1e9dd7de705..15bc7ab458dc 100644
> --- a/kernel/cgroup/rstat.c
> +++ b/kernel/cgroup/rstat.c
> @@ -14,6 +14,17 @@ static DEFINE_PER_CPU(raw_spinlock_t, rstat_base_cpu_lock);
>  
>  static void cgroup_base_stat_flush(struct cgroup *cgrp, int cpu);
>  
> +/*
> + * Determines whether a given css can participate in rstat.
> + * css's that are cgroup::self use rstat for base stats.
> + * Other css's associated with a subsystem use rstat when they
> + * define the ss->css_rstat_flush callback.
> + */
> +static inline bool is_rstat_css(struct cgroup_subsys_state *css)

css_uses_rstat() is probably a better name.