From cf475ad28ac35cc9ba612d67158f29b73b38b05d Mon Sep 17 00:00:00 2001 From: Balbir Singh Date: Tue, 29 Apr 2008 01:00:16 -0700 Subject: cgroups: add an owner to the mm_struct Remove the mem_cgroup member from mm_struct and instead adds an owner. This approach was suggested by Paul Menage. The advantage of this approach is that, once the mm->owner is known, using the subsystem id, the cgroup can be determined. It also allows several control groups that are virtually grouped by mm_struct, to exist independent of the memory controller i.e., without adding mem_cgroup's for each controller, to mm_struct. A new config option CONFIG_MM_OWNER is added and the memory resource controller selects this config option. This patch also adds cgroup callbacks to notify subsystems when mm->owner changes. The mm_cgroup_changed callback is called with the task_lock() of the new task held and is called just prior to changing the mm->owner. I am indebted to Paul Menage for the several reviews of this patchset and helping me make it lighter and simpler. This patch was tested on a powerpc box, it was compiled with both the MM_OWNER config turned on and off. After the thread group leader exits, it's moved to init_css_state by cgroup_exit(), thus all future charges from runnings threads would be redirected to the init_css_set's subsystem. Signed-off-by: Balbir Singh Cc: Pavel Emelianov Cc: Hugh Dickins Cc: Sudhir Kumar Cc: YAMAMOTO Takashi Cc: Hirokazu Takahashi Cc: David Rientjes , Cc: Balbir Singh Acked-by: KAMEZAWA Hiroyuki Acked-by: Pekka Enberg Reviewed-by: Paul Menage Cc: Oleg Nesterov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/memcontrol.c | 28 +++++----------------------- 1 file changed, 5 insertions(+), 23 deletions(-) (limited to 'mm') diff --git a/mm/memcontrol.c b/mm/memcontrol.c index d12795cc7622..49d80814798b 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -236,26 +236,12 @@ static struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont) css); } -static struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p) +struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p) { return container_of(task_subsys_state(p, mem_cgroup_subsys_id), struct mem_cgroup, css); } -void mm_init_cgroup(struct mm_struct *mm, struct task_struct *p) -{ - struct mem_cgroup *mem; - - mem = mem_cgroup_from_task(p); - css_get(&mem->css); - mm->mem_cgroup = mem; -} - -void mm_free_cgroup(struct mm_struct *mm) -{ - css_put(&mm->mem_cgroup->css); -} - static inline int page_cgroup_locked(struct page *page) { return bit_spin_is_locked(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup); @@ -476,6 +462,7 @@ unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan, int zid = zone_idx(z); struct mem_cgroup_per_zone *mz; + BUG_ON(!mem_cont); mz = mem_cgroup_zoneinfo(mem_cont, nid, zid); if (active) src = &mz->active_list; @@ -574,7 +561,7 @@ retry: mm = &init_mm; rcu_read_lock(); - mem = rcu_dereference(mm->mem_cgroup); + mem = mem_cgroup_from_task(rcu_dereference(mm->owner)); /* * For every charge from the cgroup, increment reference count */ @@ -985,10 +972,9 @@ mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont) struct mem_cgroup *mem; int node; - if (unlikely((cont->parent) == NULL)) { + if (unlikely((cont->parent) == NULL)) mem = &init_mem_cgroup; - init_mm.mem_cgroup = mem; - } else + else mem = kzalloc(sizeof(struct mem_cgroup), GFP_KERNEL); if (mem == NULL) @@ -1067,10 +1053,6 @@ static void mem_cgroup_move_task(struct cgroup_subsys *ss, if (!thread_group_leader(p)) goto out; - css_get(&mem->css); - rcu_assign_pointer(mm->mem_cgroup, mem); - css_put(&old_mem->css); - out: mmput(mm); } -- cgit v1.2.3