korg/linux
0
0
Fork 0
mirror of https://mirrors.bfsu.edu.cn/git/linux.git synced 2024-11-11 04:18:39 +08:00
Code Issues Packages Projects Releases Wiki Activity

mm: memcontrol: remove kmemcg_id reparenting

Browse Source 
Since slab objects and kmem pages are charged to object cgroup instead
of memory cgroup, memcg_reparent_objcgs() will reparent this cgroup and
all its descendants to its parent cgroup.  This already makes further
list_lru_add()'s add elements to the parent's list.  So it is
unnecessary to change kmemcg_id of an offline cgroup to its parent's id.
It just wastes CPU cycles.  Just remove the redundant code.

Link: https://lkml.kernel.org/r/20211025125102.56533-1-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Roman Gushchin <guro@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Muchun Song 2021-11-05 13:37:53 -07:00 committed by Linus Torvalds
parent 41d17431df
commit 6426886811
1 changed files with 4 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
mm/memcontrol.c
View File

@ -3650,8 +3650,7 @@ static int memcg_online_kmem(struct mem_cgroup *memcg)
static void memcg_offline_kmem(struct mem_cgroup *memcg)
{
struct cgroup_subsys_state *css;
struct mem_cgroup *parent, *child;
struct mem_cgroup *parent;
int kmemcg_id;
if (memcg->kmem_state != KMEM_ONLINE)
@ -3669,21 +3668,11 @@ static void memcg_offline_kmem(struct mem_cgroup *memcg)
BUG_ON(kmemcg_id < 0);
/*
* Change kmemcg_id of this cgroup and all its descendants to the
* parent's id, and then move all entries from this cgroup's list_lrus
* to ones of the parent. After we have finished, all list_lrus
* corresponding to this cgroup are guaranteed to remain empty. The
* ordering is imposed by list_lru_node->lock taken by
* After we have finished memcg_reparent_objcgs(), all list_lrus
* corresponding to this cgroup are guaranteed to remain empty.
* The ordering is imposed by list_lru_node->lock taken by
* memcg_drain_all_list_lrus().
*/
rcu_read_lock(); /* can be called from css_free w/o cgroup_mutex */
css_for_each_descendant_pre(css, &memcg->css) {
child = mem_cgroup_from_css(css);
BUG_ON(child->kmemcg_id != kmemcg_id);
child->kmemcg_id = parent->kmemcg_id;
}
rcu_read_unlock();
memcg_drain_all_list_lrus(kmemcg_id, parent);
memcg_free_cache_id(kmemcg_id);