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 <balbir@linux.vnet.ibm.com>
Cc: Pavel Emelianov <xemul@openvz.org>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Sudhir Kumar <skumar@linux.vnet.ibm.com>
Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Cc: Hirokazu Takahashi <taka@valinux.co.jp>
Cc: David Rientjes <rientjes@google.com>,
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Reviewed-by: Paul Menage <menage@google.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Balbir Singh 2008-04-29 01:00:16 -07:00 committed by Linus Torvalds
parent 29486df325
commit cf475ad28a
11 changed files with 169 additions and 41 deletions

View File

@ -735,6 +735,7 @@ static int exec_mmap(struct mm_struct *mm)
tsk->active_mm = mm;
activate_mm(active_mm, mm);
task_unlock(tsk);
mm_update_next_owner(mm);
arch_pick_mmap_layout(mm);
if (old_mm) {
up_read(&old_mm->mmap_sem);

View File

@ -305,6 +305,12 @@ struct cgroup_subsys {
struct cgroup *cgrp);
void (*post_clone)(struct cgroup_subsys *ss, struct cgroup *cgrp);
void (*bind)(struct cgroup_subsys *ss, struct cgroup *root);
/*
* This routine is called with the task_lock of mm->owner held
*/
void (*mm_owner_changed)(struct cgroup_subsys *ss,
struct cgroup *old,
struct cgroup *new);
int subsys_id;
int active;
int disabled;
@ -390,4 +396,13 @@ static inline int cgroupstats_build(struct cgroupstats *stats,
#endif /* !CONFIG_CGROUPS */
#ifdef CONFIG_MM_OWNER
extern void
cgroup_mm_owner_callbacks(struct task_struct *old, struct task_struct *new);
#else /* !CONFIG_MM_OWNER */
static inline void
cgroup_mm_owner_callbacks(struct task_struct *old, struct task_struct *new)
{
}
#endif /* CONFIG_MM_OWNER */
#endif /* _LINUX_CGROUP_H */

View File

@ -27,9 +27,6 @@ struct mm_struct;
#ifdef CONFIG_CGROUP_MEM_RES_CTLR
extern void mm_init_cgroup(struct mm_struct *mm, struct task_struct *p);
extern void mm_free_cgroup(struct mm_struct *mm);
#define page_reset_bad_cgroup(page) ((page)->page_cgroup = 0)
extern struct page_cgroup *page_get_page_cgroup(struct page *page);
@ -48,8 +45,10 @@ extern unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
extern void mem_cgroup_out_of_memory(struct mem_cgroup *mem, gfp_t gfp_mask);
int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem);
extern struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p);
#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);
@ -73,15 +72,6 @@ extern long mem_cgroup_calc_reclaim_inactive(struct mem_cgroup *mem,
struct zone *zone, int priority);
#else /* CONFIG_CGROUP_MEM_RES_CTLR */
static inline void mm_init_cgroup(struct mm_struct *mm,
struct task_struct *p)
{
}
static inline void mm_free_cgroup(struct mm_struct *mm)
{
}
static inline void page_reset_bad_cgroup(struct page *page)
{
}

View File

@ -225,8 +225,9 @@ struct mm_struct {
/* aio bits */
rwlock_t ioctx_list_lock; /* aio lock */
struct kioctx *ioctx_list;
#ifdef CONFIG_CGROUP_MEM_RES_CTLR
struct mem_cgroup *mem_cgroup;
#ifdef CONFIG_MM_OWNER
struct task_struct *owner; /* The thread group leader that */
/* owns the mm_struct. */
#endif
};

View File

@ -2148,6 +2148,19 @@ static inline void migration_init(void)
#define TASK_SIZE_OF(tsk) TASK_SIZE
#endif
#ifdef CONFIG_MM_OWNER
extern void mm_update_next_owner(struct mm_struct *mm);
extern void mm_init_owner(struct mm_struct *mm, struct task_struct *p);
#else
static inline void mm_update_next_owner(struct mm_struct *mm)
{
}
static inline void mm_init_owner(struct mm_struct *mm, struct task_struct *p)
{
}
#endif /* CONFIG_MM_OWNER */
#endif /* __KERNEL__ */
#endif

View File

@ -378,9 +378,13 @@ config RESOURCE_COUNTERS
infrastructure that works with cgroups
depends on CGROUPS
config MM_OWNER
bool
config CGROUP_MEM_RES_CTLR
bool "Memory Resource Controller for Control Groups"
depends on CGROUPS && RESOURCE_COUNTERS
select MM_OWNER
help
Provides a memory resource controller that manages both page cache and
RSS memory.
@ -393,6 +397,9 @@ config CGROUP_MEM_RES_CTLR
Only enable when you're ok with these trade offs and really
sure you need the memory resource controller.
This config option also selects MM_OWNER config option, which
could in turn add some fork/exit overhead.
config SYSFS_DEPRECATED
bool

View File

@ -559,6 +559,7 @@ asmlinkage void __init start_kernel(void)
printk(KERN_NOTICE);
printk(linux_banner);
setup_arch(&command_line);
mm_init_owner(&init_mm, &init_task);
setup_command_line(command_line);
unwind_setup();
setup_per_cpu_areas();

View File

@ -119,6 +119,7 @@ static int root_count;
* be called.
*/
static int need_forkexit_callback;
static int need_mm_owner_callback __read_mostly;
/* convenient tests for these bits */
inline int cgroup_is_removed(const struct cgroup *cgrp)
@ -2498,6 +2499,7 @@ static void __init cgroup_init_subsys(struct cgroup_subsys *ss)
init_css_set.subsys[ss->subsys_id] = dummytop->subsys[ss->subsys_id];
need_forkexit_callback |= ss->fork || ss->exit;
need_mm_owner_callback |= !!ss->mm_owner_changed;
/* At system boot, before all subsystems have been
* registered, no tasks have been forked, so we don't
@ -2748,6 +2750,34 @@ void cgroup_fork_callbacks(struct task_struct *child)
}
}
#ifdef CONFIG_MM_OWNER
/**
* cgroup_mm_owner_callbacks - run callbacks when the mm->owner changes
* @p: the new owner
*
* Called on every change to mm->owner. mm_init_owner() does not
* invoke this routine, since it assigns the mm->owner the first time
* and does not change it.
*/
void cgroup_mm_owner_callbacks(struct task_struct *old, struct task_struct *new)
{
struct cgroup *oldcgrp, *newcgrp;
if (need_mm_owner_callback) {
int i;
for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
struct cgroup_subsys *ss = subsys[i];
oldcgrp = task_cgroup(old, ss->subsys_id);
newcgrp = task_cgroup(new, ss->subsys_id);
if (oldcgrp == newcgrp)
continue;
if (ss->mm_owner_changed)
ss->mm_owner_changed(ss, oldcgrp, newcgrp);
}
}
}
#endif /* CONFIG_MM_OWNER */
/**
* cgroup_post_fork - called on a new task after adding it to the task list
* @child: the task in question

View File

@ -557,6 +557,88 @@ void exit_fs(struct task_struct *tsk)
EXPORT_SYMBOL_GPL(exit_fs);
#ifdef CONFIG_MM_OWNER
/*
* Task p is exiting and it owned mm, lets find a new owner for it
*/
static inline int
mm_need_new_owner(struct mm_struct *mm, struct task_struct *p)
{
/*
* If there are other users of the mm and the owner (us) is exiting
* we need to find a new owner to take on the responsibility.
*/
if (!mm)
return 0;
if (atomic_read(&mm->mm_users) <= 1)
return 0;
if (mm->owner != p)
return 0;
return 1;
}
void mm_update_next_owner(struct mm_struct *mm)
{
struct task_struct *c, *g, *p = current;
retry:
if (!mm_need_new_owner(mm, p))
return;
read_lock(&tasklist_lock);
/*
* Search in the children
*/
list_for_each_entry(c, &p->children, sibling) {
if (c->mm == mm)
goto assign_new_owner;
}
/*
* Search in the siblings
*/
list_for_each_entry(c, &p->parent->children, sibling) {
if (c->mm == mm)
goto assign_new_owner;
}
/*
* Search through everything else. We should not get
* here often
*/
do_each_thread(g, c) {
if (c->mm == mm)
goto assign_new_owner;
} while_each_thread(g, c);
read_unlock(&tasklist_lock);
return;
assign_new_owner:
BUG_ON(c == p);
get_task_struct(c);
/*
* The task_lock protects c->mm from changing.
* We always want mm->owner->mm == mm
*/
task_lock(c);
/*
* Delay read_unlock() till we have the task_lock()
* to ensure that c does not slip away underneath us
*/
read_unlock(&tasklist_lock);
if (c->mm != mm) {
task_unlock(c);
put_task_struct(c);
goto retry;
}
cgroup_mm_owner_callbacks(mm->owner, c);
mm->owner = c;
task_unlock(c);
put_task_struct(c);
}
#endif /* CONFIG_MM_OWNER */
/*
* Turn us into a lazy TLB process if we
* aren't already..
@ -596,6 +678,7 @@ static void exit_mm(struct task_struct * tsk)
/* We don't want this task to be frozen prematurely */
clear_freeze_flag(tsk);
task_unlock(tsk);
mm_update_next_owner(mm);
mmput(mm);
}

View File

@ -381,14 +381,13 @@ static struct mm_struct * mm_init(struct mm_struct * mm, struct task_struct *p)
mm->ioctx_list = NULL;
mm->free_area_cache = TASK_UNMAPPED_BASE;
mm->cached_hole_size = ~0UL;
mm_init_cgroup(mm, p);
mm_init_owner(mm, p);
if (likely(!mm_alloc_pgd(mm))) {
mm->def_flags = 0;
return mm;
}
mm_free_cgroup(mm);
free_mm(mm);
return NULL;
}
@ -438,7 +437,6 @@ void mmput(struct mm_struct *mm)
spin_unlock(&mmlist_lock);
}
put_swap_token(mm);
mm_free_cgroup(mm);
mmdrop(mm);
}
}
@ -982,6 +980,13 @@ static void rt_mutex_init_task(struct task_struct *p)
#endif
}
#ifdef CONFIG_MM_OWNER
void mm_init_owner(struct mm_struct *mm, struct task_struct *p)
{
mm->owner = p;
}
#endif /* CONFIG_MM_OWNER */
/*
* This creates a new process as a copy of the old one,
* but does not actually start it yet.

View File

@ -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);
}