On Thu, Nov 30, 2023 at 11:40 AM Nhat Pham nphamcs@gmail.com wrote:
This patch implements a helper function that try to get a reference to an memcg's css, as well as checking if it is online. This new function is almost exactly the same as the existing mem_cgroup_tryget(), except for the onlineness check. In the !CONFIG_MEMCG case, it always returns true, analogous to mem_cgroup_tryget(). This is useful for e.g to the new zswap writeback scheme, where we need to select the next online memcg as a candidate for the global limit reclaim.
Signed-off-by: Nhat Pham nphamcs@gmail.com
Reviewed-by: Yosry Ahmed yosryahmed@google.com
include/linux/memcontrol.h | 10 ++++++++++ 1 file changed, 10 insertions(+)
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 7bdcf3020d7a..2bd7d14ace78 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -821,6 +821,11 @@ static inline bool mem_cgroup_tryget(struct mem_cgroup *memcg) return !memcg || css_tryget(&memcg->css); }
+static inline bool mem_cgroup_tryget_online(struct mem_cgroup *memcg) +{
return !memcg || css_tryget_online(&memcg->css);+}
static inline void mem_cgroup_put(struct mem_cgroup *memcg) { if (memcg) @@ -1349,6 +1354,11 @@ static inline bool mem_cgroup_tryget(struct mem_cgroup *memcg) return true; }
+static inline bool mem_cgroup_tryget_online(struct mem_cgroup *memcg) +{
return true;+}
static inline void mem_cgroup_put(struct mem_cgroup *memcg) { } -- 2.34.1