On Mon Jan 22, 2024 at 7:20 PM EET, Haitao Huang wrote:
> From: Kristen Carlson Accardi <kristen@xxxxxxxxxxxxxxx>
>
> The SGX EPC cgroup will reclaim EPC pages when a usage in a cgroup
> reaches its or ancestor's limit. This requires a walk from the current
> cgroup up to the root similar to misc_cg_try_charge(). Export
> misc_cg_parent() to enable this walk.
>
> The SGX driver may also need start a global level reclamation from the
> root. Export misc_cg_root() for the SGX driver to access.
>
> Signed-off-by: Kristen Carlson Accardi <kristen@xxxxxxxxxxxxxxx>
> Co-developed-by: Haitao Huang <haitao.huang@xxxxxxxxxxxxxxx>
> Signed-off-by: Haitao Huang <haitao.huang@xxxxxxxxxxxxxxx>
> ---
> V6:
> - Make commit messages more concise and split the original patch into two(Kai)
> ---
> include/linux/misc_cgroup.h | 24 ++++++++++++++++++++++++
> kernel/cgroup/misc.c | 21 ++++++++-------------
> 2 files changed, 32 insertions(+), 13 deletions(-)
>
> diff --git a/include/linux/misc_cgroup.h b/include/linux/misc_cgroup.h
> index 0806d4436208..541a5611c597 100644
> --- a/include/linux/misc_cgroup.h
> +++ b/include/linux/misc_cgroup.h
> @@ -64,6 +64,7 @@ struct misc_cg {
> struct misc_res res[MISC_CG_RES_TYPES];
> };
>
> +struct misc_cg *misc_cg_root(void);
> u64 misc_cg_res_total_usage(enum misc_res_type type);
> int misc_cg_set_capacity(enum misc_res_type type, u64 capacity);
> int misc_cg_set_ops(enum misc_res_type type, const struct misc_res_ops *ops);
> @@ -84,6 +85,20 @@ static inline struct misc_cg *css_misc(struct cgroup_subsys_state *css)
> return css ? container_of(css, struct misc_cg, css) : NULL;
> }
>
> +/**
> + * misc_cg_parent() - Get the parent of the passed misc cgroup.
> + * @cgroup: cgroup whose parent needs to be fetched.
> + *
> + * Context: Any context.
> + * Return:
> + * * struct misc_cg* - Parent of the @cgroup.
> + * * %NULL - If @cgroup is null or the passed cgroup does not have a parent.
> + */
> +static inline struct misc_cg *misc_cg_parent(struct misc_cg *cgroup)
> +{
> + return cgroup ? css_misc(cgroup->css.parent) : NULL;
> +}
> +
> /*
> * get_current_misc_cg() - Find and get the misc cgroup of the current task.
> *
> @@ -108,6 +123,15 @@ static inline void put_misc_cg(struct misc_cg *cg)
> }
>
> #else /* !CONFIG_CGROUP_MISC */
> +static inline struct misc_cg *misc_cg_root(void)
> +{
> + return NULL;
> +}
> +
> +static inline struct misc_cg *misc_cg_parent(struct misc_cg *cg)
> +{
> + return NULL;
> +}
>
> static inline u64 misc_cg_res_total_usage(enum misc_res_type type)
> {
> diff --git a/kernel/cgroup/misc.c b/kernel/cgroup/misc.c
> index b8c32791334c..99d971ecc842 100644
> --- a/kernel/cgroup/misc.c
> +++ b/kernel/cgroup/misc.c
> @@ -43,18 +43,13 @@ static u64 misc_res_capacity[MISC_CG_RES_TYPES];
> static const struct misc_res_ops *misc_res_ops[MISC_CG_RES_TYPES];
>
> /**
> - * parent_misc() - Get the parent of the passed misc cgroup.
> - * @cgroup: cgroup whose parent needs to be fetched.
> - *
> - * Context: Any context.
> - * Return:
> - * * struct misc_cg* - Parent of the @cgroup.
> - * * %NULL - If @cgroup is null or the passed cgroup does not have a parent.
> + * misc_cg_root() - Return the root misc cgroup.
> */
> -static struct misc_cg *parent_misc(struct misc_cg *cgroup)
> +struct misc_cg *misc_cg_root(void)
> {
> - return cgroup ? css_misc(cgroup->css.parent) : NULL;
> + return &root_cg;
> }
> +EXPORT_SYMBOL_GPL(misc_cg_root);
>
> /**
> * valid_type() - Check if @type is valid or not.
> @@ -183,7 +178,7 @@ int misc_cg_try_charge(enum misc_res_type type, struct misc_cg *cg, u64 amount)
> if (!amount)
> return 0;
>
> - for (i = cg; i; i = parent_misc(i)) {
> + for (i = cg; i; i = misc_cg_parent(i)) {
> res = &i->res[type];
>
> new_usage = atomic64_add_return(amount, &res->usage);
> @@ -196,12 +191,12 @@ int misc_cg_try_charge(enum misc_res_type type, struct misc_cg *cg, u64 amount)
> return 0;
>
> err_charge:
> - for (j = i; j; j = parent_misc(j)) {
> + for (j = i; j; j = misc_cg_parent(j)) {
> atomic64_inc(&j->res[type].events);
> cgroup_file_notify(&j->events_file);
> }
>
> - for (j = cg; j != i; j = parent_misc(j))
> + for (j = cg; j != i; j = misc_cg_parent(j))
> misc_cg_cancel_charge(type, j, amount);
> misc_cg_cancel_charge(type, i, amount);
> return ret;
> @@ -223,7 +218,7 @@ void misc_cg_uncharge(enum misc_res_type type, struct misc_cg *cg, u64 amount)
> if (!(amount && valid_type(type) && cg))
> return;
>
> - for (i = cg; i; i = parent_misc(i))
> + for (i = cg; i; i = misc_cg_parent(i))
> misc_cg_cancel_charge(type, i, amount);
> }
> EXPORT_SYMBOL_GPL(misc_cg_uncharge);
Reviewed-by: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
BR, Jarkko
