diff options
author | Tejun Heo <tj@kernel.org> | 2013-08-09 00:11:23 (GMT) |
---|---|---|
committer | Tejun Heo <tj@kernel.org> | 2013-08-09 00:11:23 (GMT) |
commit | 6387698699afd72d6304566fb6ccf84bffe07c56 (patch) | |
tree | 9440e96fa8e5adce62409a5b0e40984dfedaada3 /mm/memcontrol.c | |
parent | a7c6d554aa01236ac2a9f851ab0f75704f76dfa2 (diff) | |
download | linux-6387698699afd72d6304566fb6ccf84bffe07c56.tar.xz |
cgroup: add css_parent()
Currently, controllers have to explicitly follow the cgroup hierarchy
to find the parent of a given css. cgroup is moving towards using
cgroup_subsys_state as the main controller interface construct, so
let's provide a way to climb the hierarchy using just csses.
This patch implements css_parent() which, given a css, returns its
parent. The function is guarnateed to valid non-NULL parent css as
long as the target css is not at the top of the hierarchy.
freezer, cpuset, cpu, cpuacct, hugetlb, memory, net_cls and devices
are converted to use css_parent() instead of accessing cgroup->parent
directly.
* __parent_ca() is dropped from cpuacct and its usage is replaced with
parent_ca(). The only difference between the two was NULL test on
cgroup->parent which is now embedded in css_parent() making the
distinction moot. Note that eventually a css->parent field will be
added to css and the NULL check in css_parent() will go away.
This patch shouldn't cause any behavior differences.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Diffstat (limited to 'mm/memcontrol.c')
-rw-r--r-- | mm/memcontrol.c | 39 |
1 files changed, 11 insertions, 28 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 11d659e..69b3e52 100644 --- 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; |