[RFC][-mm] Memory controller add mm->owner
From: Balbir Singh
Date: Mon Mar 24 2008 - 10:05:02 EST
This patch removes 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.
The code initially assigns mm->owner to the task and then after the
thread group leader is identified. The mm->owner is changed to the thread
group leader of the task later at the end of copy_process.
Signed-off-by: Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx>
---
include/linux/memcontrol.h | 14 +++++++++++++-
include/linux/mm_types.h | 5 ++++-
kernel/fork.c | 4 ++++
mm/memcontrol.c | 42 ++++++++++++++++++++++++++++++++++--------
4 files changed, 55 insertions(+), 10 deletions(-)
diff -puN include/linux/mm_types.h~memory-controller-add-mm-owner include/linux/mm_types.h
--- linux-2.6.25-rc5/include/linux/mm_types.h~memory-controller-add-mm-owner 2008-03-20 13:35:09.000000000 +0530
+++ linux-2.6.25-rc5-balbir/include/linux/mm_types.h 2008-03-20 15:11:05.000000000 +0530
@@ -228,7 +228,10 @@ struct mm_struct {
rwlock_t ioctx_list_lock;
struct kioctx *ioctx_list;
#ifdef CONFIG_CGROUP_MEM_RES_CTLR
- struct mem_cgroup *mem_cgroup;
+ struct task_struct *owner; /* The thread group leader that */
+ /* owns the mm_struct. This */
+ /* might be useful even outside */
+ /* of the config option */
#endif
#ifdef CONFIG_PROC_FS
diff -puN kernel/fork.c~memory-controller-add-mm-owner kernel/fork.c
--- linux-2.6.25-rc5/kernel/fork.c~memory-controller-add-mm-owner 2008-03-20 13:35:09.000000000 +0530
+++ linux-2.6.25-rc5-balbir/kernel/fork.c 2008-03-24 18:49:29.000000000 +0530
@@ -1357,6 +1357,10 @@ static struct task_struct *copy_process(
write_unlock_irq(&tasklist_lock);
proc_fork_connector(p);
cgroup_post_fork(p);
+
+ if (!(clone_flags & CLONE_VM))
+ mem_cgroup_fork_init(p);
+
return p;
bad_fork_free_pid:
diff -puN include/linux/memcontrol.h~memory-controller-add-mm-owner include/linux/memcontrol.h
--- linux-2.6.25-rc5/include/linux/memcontrol.h~memory-controller-add-mm-owner 2008-03-20 13:35:09.000000000 +0530
+++ linux-2.6.25-rc5-balbir/include/linux/memcontrol.h 2008-03-24 18:49:52.000000000 +0530
@@ -29,6 +29,7 @@ struct mm_struct;
extern void mm_init_cgroup(struct mm_struct *mm, struct task_struct *p);
extern void mm_free_cgroup(struct mm_struct *mm);
+extern void mem_cgroup_fork_init(struct task_struct *p);
#define page_reset_bad_cgroup(page) ((page)->page_cgroup = 0)
@@ -49,7 +50,7 @@ extern void mem_cgroup_out_of_memory(str
int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem);
#define mm_match_cgroup(mm, cgroup) \
- ((cgroup) == rcu_dereference((mm)->mem_cgroup))
+ ((cgroup) == mem_cgroup_from_task((mm)->owner))
extern int mem_cgroup_prepare_migration(struct page *page);
extern void mem_cgroup_end_migration(struct page *page);
@@ -72,6 +73,8 @@ extern long mem_cgroup_calc_reclaim_acti
extern long mem_cgroup_calc_reclaim_inactive(struct mem_cgroup *mem,
struct zone *zone, int priority);
+extern struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p);
+
#else /* CONFIG_CGROUP_MEM_RES_CTLR */
static inline void mm_init_cgroup(struct mm_struct *mm,
struct task_struct *p)
@@ -82,6 +85,10 @@ static inline void mm_free_cgroup(struct
{
}
+static inline void mem_cgroup_fork_init(struct task_struct *p)
+{
+}
+
static inline void page_reset_bad_cgroup(struct page *page)
{
}
@@ -172,6 +179,11 @@ static inline long mem_cgroup_calc_recla
{
return 0;
}
+
+static void mm_free_fork_cgroup(struct task_struct *p)
+{
+}
+
#endif /* CONFIG_CGROUP_MEM_CONT */
#endif /* _LINUX_MEMCONTROL_H */
diff -puN mm/memcontrol.c~memory-controller-add-mm-owner mm/memcontrol.c
--- linux-2.6.25-rc5/mm/memcontrol.c~memory-controller-add-mm-owner 2008-03-20 13:35:09.000000000 +0530
+++ linux-2.6.25-rc5-balbir/mm/memcontrol.c 2008-03-24 19:04:32.000000000 +0530
@@ -236,7 +236,7 @@ static struct mem_cgroup *mem_cgroup_fro
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);
@@ -248,12 +248,40 @@ void mm_init_cgroup(struct mm_struct *mm
mem = mem_cgroup_from_task(p);
css_get(&mem->css);
- mm->mem_cgroup = mem;
+ mm->owner = p;
+}
+
+void mem_cgroup_fork_init(struct task_struct *p)
+{
+ struct mm_struct *mm = get_task_mm(p);
+ struct mem_cgroup *mem, *oldmem;
+ if (!mm)
+ return;
+
+ /*
+ * Initial owner at mm_init_cgroup() time is the task itself.
+ * The thread group leader had not been setup then
+ */
+ oldmem = mem_cgroup_from_task(mm->owner);
+ /*
+ * Override the mm->owner after we know the thread group later
+ */
+ mm->owner = p->group_leader;
+ mem = mem_cgroup_from_task(mm->owner);
+ css_get(&mem->css);
+ css_put(&oldmem->css);
+ mmput(mm);
}
void mm_free_cgroup(struct mm_struct *mm)
{
- css_put(&mm->mem_cgroup->css);
+ struct mem_cgroup *mem;
+
+ /*
+ * TODO: Should we assign mm->owner to NULL here?
+ */
+ mem = mem_cgroup_from_task(mm->owner);
+ css_put(&mem->css);
}
static inline int page_cgroup_locked(struct page *page)
@@ -476,6 +504,7 @@ unsigned long mem_cgroup_isolate_pages(u
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;
@@ -573,13 +602,11 @@ retry:
if (!mm)
mm = &init_mm;
- rcu_read_lock();
- mem = rcu_dereference(mm->mem_cgroup);
+ mem = mem_cgroup_from_task(mm->owner);
/*
* For every charge from the cgroup, increment reference count
*/
css_get(&mem->css);
- rcu_read_unlock();
while (res_counter_charge(&mem->res, PAGE_SIZE)) {
if (!(gfp_mask & __GFP_WAIT))
@@ -988,7 +1015,7 @@ mem_cgroup_create(struct cgroup_subsys *
if (unlikely((cont->parent) == NULL)) {
mem = &init_mem_cgroup;
- init_mm.mem_cgroup = mem;
+ init_mm.owner = &init_task;
} else
mem = kzalloc(sizeof(struct mem_cgroup), GFP_KERNEL);
@@ -1069,7 +1096,6 @@ static void mem_cgroup_move_task(struct
goto out;
css_get(&mem->css);
- rcu_assign_pointer(mm->mem_cgroup, mem);
css_put(&old_mem->css);
out:
_
--
Warm Regards,
Balbir Singh
Linux Technology Center
IBM, ISTL
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