Hello Kairui,
On Thu, Feb 09, 2023 at 12:16:53AM +0800, Kairui Song wrote:
> From: Kairui Song <kasong@xxxxxxxxxxx>
>
> Since the only case where cgroup_psi should return psi_system instead of
> the cgroup's psi_group is the root cgroup, just set root cgroup's psi to
> point to psi_system to remove the if branch.
>
> Signed-off-by: Kairui Song <kasong@xxxxxxxxxxx>
Thanks for the patches. They overall look good, and the numbers even
better.
> include/linux/psi.h | 2 +-
> kernel/cgroup/cgroup.c | 7 ++++++-
> 2 files changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/psi.h b/include/linux/psi.h
> index b029a847def1..9c3a1638b618 100644
> --- a/include/linux/psi.h
> +++ b/include/linux/psi.h
> @@ -33,7 +33,7 @@ __poll_t psi_trigger_poll(void **trigger_ptr, struct file *file,
> #ifdef CONFIG_CGROUPS
> static inline struct psi_group *cgroup_psi(struct cgroup *cgrp)
> {
> - return cgroup_ino(cgrp) == 1 ? &psi_system : cgrp->psi;
> + return cgrp->psi;
> }
>
> int psi_cgroup_alloc(struct cgroup *cgrp);
> diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
> index c099cf3fa02d..1491d63b06b6 100644
> --- a/kernel/cgroup/cgroup.c
> +++ b/kernel/cgroup/cgroup.c
> @@ -163,7 +163,12 @@ static struct static_key_true *cgroup_subsys_on_dfl_key[] = {
> static DEFINE_PER_CPU(struct cgroup_rstat_cpu, cgrp_dfl_root_rstat_cpu);
>
> /* the default hierarchy */
> -struct cgroup_root cgrp_dfl_root = { .cgrp.rstat_cpu = &cgrp_dfl_root_rstat_cpu };
> +struct cgroup_root cgrp_dfl_root = {
> + .cgrp.rstat_cpu = &cgrp_dfl_root_rstat_cpu,
> +#ifdef CONFIG_PSI
> + .cgrp.psi = &psi_system
> +#endif
Nitpick: customary coding style is to keep a comma even after the last
entry in the struct. Somebody appending new things won't need to touch
the previous last line, which adds diff noise.
With that, please add:
Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
