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Commit 56161634 authored by Tejun Heo's avatar Tejun Heo Committed by Jens Axboe
Browse files

memcg: add mem_cgroup_root_css 



Add global mem_cgroup_root_css which points to the root memcg css.
This will be used by cgroup writeback support.  If memcg is disabled,
it's defined as ERR_PTR(-EINVAL).

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
aCc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent ec13b1d6

include/linux/memcontrol.h

+4 −0
Original line number Diff line number Diff line
@@ -68,6 +68,8 @@ enum mem_cgroup_events_index { 
};



#ifdef CONFIG_MEMCG

extern struct cgroup_subsys_state *mem_cgroup_root_css;



void mem_cgroup_events(struct mem_cgroup *memcg,

		       enum mem_cgroup_events_index idx,

		       unsigned int nr);
@@ -196,6 +198,8 @@ void mem_cgroup_split_huge_fixup(struct page *head); 
#else /* CONFIG_MEMCG */

struct mem_cgroup;



#define mem_cgroup_root_css ((struct cgroup_subsys_state *)ERR_PTR(-EINVAL))



static inline void mem_cgroup_events(struct mem_cgroup *memcg,

				     enum mem_cgroup_events_index idx,

				     unsigned int nr)

mm/memcontrol.c

+2 −0
Original line number Diff line number Diff line
@@ -77,6 +77,7 @@ EXPORT_SYMBOL(memory_cgrp_subsys); 


#define MEM_CGROUP_RECLAIM_RETRIES	5

static struct mem_cgroup *root_mem_cgroup __read_mostly;

struct cgroup_subsys_state *mem_cgroup_root_css __read_mostly;



/* Whether the swap controller is active */

#ifdef CONFIG_MEMCG_SWAP
@@ -4441,6 +4442,7 @@ mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) 
	/* root ? */

	if (parent_css == NULL) {

		root_mem_cgroup = memcg;

		mem_cgroup_root_css = &memcg->css;

		page_counter_init(&memcg->memory, NULL);

		memcg->high = PAGE_COUNTER_MAX;

		memcg->soft_limit = PAGE_COUNTER_MAX;