cgroup: add css_parent()

[linux-2.6-block.git] / mm / memcontrol.c

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 11d659e3b08ede8bdf7a8f5b15452e0a013d67d2..69b3e520f9211afdce2cb533a5256d9baf048871 100644 (file)
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1524,10 +1524,8 @@ static unsigned long mem_cgroup_margin(struct mem_cgroup *memcg)
 
 int mem_cgroup_swappiness(struct mem_cgroup *memcg)
 {
-       struct cgroup *cgrp = memcg->css.cgroup;
-
        /* root ? */
-       if (cgrp->parent == NULL)
+       if (!css_parent(&memcg->css))
                return vm_swappiness;
 
        return memcg->swappiness;
@@ -5026,11 +5024,7 @@ static int mem_cgroup_hierarchy_write(struct cgroup *cont, struct cftype *cft,
 {
        int retval = 0;
        struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
-       struct cgroup *parent = cont->parent;
-       struct mem_cgroup *parent_memcg = NULL;
-
-       if (parent)
-               parent_memcg = mem_cgroup_from_cont(parent);
+       struct mem_cgroup *parent_memcg = mem_cgroup_from_css(css_parent(&memcg->css));
 
        mutex_lock(&memcg_create_mutex);
 
@@ -5282,18 +5276,15 @@ static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
 static void memcg_get_hierarchical_limit(struct mem_cgroup *memcg,
                unsigned long long *mem_limit, unsigned long long *memsw_limit)
 {
-       struct cgroup *cgroup;
        unsigned long long min_limit, min_memsw_limit, tmp;
 
        min_limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
        min_memsw_limit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
-       cgroup = memcg->css.cgroup;
        if (!memcg->use_hierarchy)
                goto out;
 
-       while (cgroup->parent) {
-               cgroup = cgroup->parent;
-               memcg = mem_cgroup_from_cont(cgroup);
+       while (css_parent(&memcg->css)) {
+               memcg = mem_cgroup_from_css(css_parent(&memcg->css));
                if (!memcg->use_hierarchy)
                        break;
                tmp = res_counter_read_u64(&memcg->res, RES_LIMIT);
@@ -5523,16 +5514,11 @@ static int mem_cgroup_swappiness_write(struct cgroup *cgrp, struct cftype *cft,
                                       u64 val)
 {
        struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
-       struct mem_cgroup *parent;
-
-       if (val > 100)
-               return -EINVAL;
+       struct mem_cgroup *parent = mem_cgroup_from_css(css_parent(&memcg->css));
 
-       if (cgrp->parent == NULL)
+       if (val > 100 || !parent)
                return -EINVAL;
 
-       parent = mem_cgroup_from_cont(cgrp->parent);
-
        mutex_lock(&memcg_create_mutex);
 
        /* If under hierarchy, only empty-root can set this value */
@@ -5861,14 +5847,12 @@ static int mem_cgroup_oom_control_write(struct cgroup *cgrp,
        struct cftype *cft, u64 val)
 {
        struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
-       struct mem_cgroup *parent;
+       struct mem_cgroup *parent = mem_cgroup_from_css(css_parent(&memcg->css));
 
        /* cannot set to root cgroup and only 0 and 1 are allowed */
-       if (!cgrp->parent || !((val == 0) || (val == 1)))
+       if (!parent || !((val == 0) || (val == 1)))
                return -EINVAL;
 
-       parent = mem_cgroup_from_cont(cgrp->parent);
-
        mutex_lock(&memcg_create_mutex);
        /* oom-kill-disable is a flag for subhierarchy. */
        if ((parent->use_hierarchy) || memcg_has_children(memcg)) {
@@ -6266,15 +6250,14 @@ free_out:
 static int
 mem_cgroup_css_online(struct cgroup *cont)
 {
-       struct mem_cgroup *memcg, *parent;
+       struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
+       struct mem_cgroup *parent = mem_cgroup_from_css(css_parent(&memcg->css));
        int error = 0;
 
-       if (!cont->parent)
+       if (!parent)
                return 0;
 
        mutex_lock(&memcg_create_mutex);
-       memcg = mem_cgroup_from_cont(cont);
-       parent = mem_cgroup_from_cont(cont->parent);
 
        memcg->use_hierarchy = parent->use_hierarchy;
        memcg->oom_kill_disable = parent->oom_kill_disable;