2022-11-11 18:48:30

by Kristen Carlson Accardi

Subject: [PATCH 20/26] cgroup/misc: allow users of misc cgroup to read specific cgroup usage

Add a function to return the current usage of the specified cgroup.
The SGX driver will need this information to decide whether to
reclaim EPC pages from a cgroup.

Signed-off-by: Kristen Carlson Accardi <[email protected]>
---
include/linux/misc_cgroup.h | 6 ++++++
kernel/cgroup/misc.c | 19 +++++++++++++++++++
2 files changed, 25 insertions(+)

diff --git a/include/linux/misc_cgroup.h b/include/linux/misc_cgroup.h
index d1aeb85f2ed6..a9dd087132dc 100644
--- a/include/linux/misc_cgroup.h
+++ b/include/linux/misc_cgroup.h
@@ -61,6 +61,7 @@ struct misc_cg {

struct misc_cg *root_misc(void);
struct misc_cg *parent_misc(struct misc_cg *cg);
+unsigned long misc_cg_read(enum misc_res_type type, struct misc_cg *cg);
unsigned long misc_cg_res_total_usage(enum misc_res_type type);
int misc_cg_set_capacity(enum misc_res_type type, unsigned long capacity);
int misc_cg_try_charge(enum misc_res_type type, struct misc_cg *cg,
@@ -118,6 +119,11 @@ static inline struct misc_cg *parent_misc(struct misc_cg *cg)
return NULL;
}

+static inline unsigned long misc_cg_read(enum misc_res_type type, struct misc_cg *cg)
+{
+ return 0;
+}
+
static inline unsigned long misc_cg_res_total_usage(enum misc_res_type type)
{
return 0;
diff --git a/kernel/cgroup/misc.c b/kernel/cgroup/misc.c
index b22a055af9ad..e2c99fdc1d40 100644
--- a/kernel/cgroup/misc.c
+++ b/kernel/cgroup/misc.c
@@ -213,6 +213,25 @@ void misc_cg_uncharge(enum misc_res_type type, struct misc_cg *cg,
}
EXPORT_SYMBOL_GPL(misc_cg_uncharge);

+/**
+ * misc_cg_read() - Return the current usage of the misc cgroup res.
+ * @type: Type of the misc res.
+ * @cg: Misc cgroup whose usage will be read
+ *
+ * Context: Any context.
+ * Return:
+ * The current total usage of the specified misc cgroup.
+ * If an invalid misc_res_type is given, zero will be returned.
+ */
+unsigned long misc_cg_read(enum misc_res_type type, struct misc_cg *cg)
+{
+ if (!(valid_type(type) && cg))
+ return 0;
+
+ return atomic_long_read(&cg->res[type].usage);
+}
+EXPORT_SYMBOL_GPL(misc_cg_read);
+
/**
* misc_cg_max_show() - Show the misc cgroup max limit.
* @sf: Interface file
--
2.37.3

2022-11-14 23:28:38

by Tejun Heo

Subject: Re: [PATCH 20/26] cgroup/misc: allow users of misc cgroup to read specific cgroup usage

On Fri, Nov 11, 2022 at 10:35:25AM -0800, Kristen Carlson Accardi wrote:
> Add a function to return the current usage of the specified cgroup.
> The SGX driver will need this information to decide whether to
> reclaim EPC pages from a cgroup.

This looks fine to me. It'd probably a good idea to keep all the interface
function names consistent with this.

Thanks.

--
tejun