mm: memcontrol: export root_mem_cgroup

A later patch will need this symbol in files other than memcontrol.c, so
export it now and replace mem_cgroup_root_css at the same time.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: David S. Miller <davem@davemloft.net>
Reviewed-by: Vladimir Davydov <vdavydov@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 78a1ec2..d0c724f 100644 (file)
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -265,7 +265,8 @@ struct mem_cgroup {
        struct mem_cgroup_per_node *nodeinfo[0];
        /* WARNING: nodeinfo must be the last member here */
 };
-extern struct cgroup_subsys_state *mem_cgroup_root_css;
+
+extern struct mem_cgroup *root_mem_cgroup;
 
 /**
  * mem_cgroup_events - count memory events against a cgroup

diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 7340353..cc5d29d 100644 (file)
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -672,7 +672,7 @@ static int cgwb_bdi_init(struct backing_dev_info *bdi)
 
        ret = wb_init(&bdi->wb, bdi, 1, GFP_KERNEL);
        if (!ret) {
-               bdi->wb.memcg_css = mem_cgroup_root_css;
+               bdi->wb.memcg_css = &root_mem_cgroup->css;
                bdi->wb.blkcg_css = blkcg_root_css;
        }
        return ret;

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 0bc140d..44ed2de 100644 (file)
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -76,9 +76,9 @@
 struct cgroup_subsys memory_cgrp_subsys __read_mostly;
 EXPORT_SYMBOL(memory_cgrp_subsys);
 
+struct mem_cgroup *root_mem_cgroup __read_mostly;
+
 #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
@@ -4241,7 +4241,6 @@ 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;