linux.git/mm/memcontrol.c, branch v3.9

memcg: initialize kmem-cache destroying work earlier

2013-03-08T23:05:34+00:00

Fix a warning from lockdep caused by calling cancel_work_sync() for
uninitialized struct work.  This path has been triggered by destructon
kmem-cache hierarchy via destroying its root kmem-cache.

  cache ffff88003c072d80
  obj ffff88003b410000 cache ffff88003c072d80
  obj ffff88003b924000 cache ffff88003c20bd40
  INFO: trying to register non-static key.
  the code is fine but needs lockdep annotation.
  turning off the locking correctness validator.
  Pid: 2825, comm: insmod Tainted: G           O 3.9.0-rc1-next-20130307+ #611
  Call Trace:
    __lock_acquire+0x16a2/0x1cb0
    lock_acquire+0x8a/0x120
    flush_work+0x38/0x2a0
    __cancel_work_timer+0x89/0xf0
    cancel_work_sync+0xb/0x10
    kmem_cache_destroy_memcg_children+0x81/0xb0
    kmem_cache_destroy+0xf/0xe0
    init_module+0xcb/0x1000 [kmem_test]
    do_one_initcall+0x11a/0x170
    load_module+0x19b0/0x2320
    SyS_init_module+0xc6/0xf0
    system_call_fastpath+0x16/0x1b

Example module to demonstrate:

  #include 
  #include 
  #include 
  #include 

  int __init mod_init(void)
  {
  	int size = 256;
  	struct kmem_cache *cache;
  	void *obj;
  	struct page *page;

  	cache = kmem_cache_create("kmem_cache_test", size, size, 0, NULL);
  	if (!cache)
  		return -ENOMEM;

  	printk("cache %p\n", cache);

  	obj = kmem_cache_alloc(cache, GFP_KERNEL);
  	if (obj) {
  		page = virt_to_head_page(obj);
  		printk("obj %p cache %p\n", obj, page->slab_cache);
  		kmem_cache_free(cache, obj);
  	}

  	flush_scheduled_work();

  	obj = kmem_cache_alloc(cache, GFP_KERNEL);
  	if (obj) {
  		page = virt_to_head_page(obj);
  		printk("obj %p cache %p\n", obj, page->slab_cache);
  		kmem_cache_free(cache, obj);
  	}

  	kmem_cache_destroy(cache);

  	return -EBUSY;
  }

  module_init(mod_init);
  MODULE_LICENSE("GPL");

Signed-off-by: Konstantin Khlebnikov 
Cc: Glauber Costa 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

memcg: stop warning on memcg_propagate_kmem

2013-02-24T01:50:22+00:00

Whilst I run the risk of a flogging for disloyalty to the Lord of Sealand,
I do have CONFIG_MEMCG=y CONFIG_MEMCG_KMEM not set, and grow tired of the
"mm/memcontrol.c:4972:12: warning: `memcg_propagate_kmem' defined but not
used [-Wunused-function]" seen in 3.8-rc: move the #ifdef outwards.

Signed-off-by: Hugh Dickins 
Acked-by: Michal Hocko 
Cc: Glauber Costa 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

memcg: cleanup mem_cgroup_init comment

2013-02-24T01:50:21+00:00

We should encourage all memcg controller initialization independent on a
specific mem_cgroup to be done here rather than exploit css_alloc
callback and assume that nothing happens before root cgroup is created.

Signed-off-by: Michal Hocko 
Acked-by: Johannes Weiner 
Cc: Tejun Heo 
Cc: KAMEZAWA Hiroyuki 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

memcg: move memcg_stock initialization to mem_cgroup_init

2013-02-24T01:50:21+00:00

memcg_stock are currently initialized during the root cgroup allocation
which is OK but it pointlessly pollutes memcg allocation code with
something that can be called when the memcg subsystem is initialized by
mem_cgroup_init along with other controller specific parts.

This patch wraps the current memcg_stock initialization code into a
helper calls it from the controller subsystem initialization code.

Signed-off-by: Michal Hocko 
Acked-by: Johannes Weiner 
Cc: Tejun Heo 
Cc: KAMEZAWA Hiroyuki 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

memcg: move mem_cgroup_soft_limit_tree_init to mem_cgroup_init

2013-02-24T01:50:21+00:00

Per-node-zone soft limit tree is currently initialized when the root
cgroup is created which is OK but it pointlessly pollutes memcg
allocation code with something that can be called when the memcg
subsystem is initialized by mem_cgroup_init along with other controller
specific parts.

While we are at it let's make mem_cgroup_soft_limit_tree_init void
because it doesn't make much sense to report memory failure because if
we fail to allocate memory that early during the boot then we are
screwed anyway (this saves some code).

Signed-off-by: Michal Hocko 
Acked-by: Johannes Weiner 
Cc: Tejun Heo 
Cc: KAMEZAWA Hiroyuki 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: refactor inactive_file_is_low() to use get_lru_size()

2013-02-24T01:50:20+00:00

An inactive file list is considered low when its active counterpart is
bigger, regardless of whether it is a global zone LRU list or a memcg
zone LRU list.  The only difference is in how the LRU size is assessed.

get_lru_size() does the right thing for both global and memcg reclaim
situations.

Get rid of inactive_file_is_low_global() and
mem_cgroup_inactive_file_is_low() by using get_lru_size() and compare
the numbers in common code.

Signed-off-by: Johannes Weiner 
Acked-by: Michal Hocko 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

memcg: avoid dangling reference count in creation failure.

2013-02-24T01:50:18+00:00

When use_hierarchy is enabled, we acquire an extra reference count in
our parent during cgroup creation.  We don't release it, though, if any
failure exist in the creation process.

Signed-off-by: Glauber Costa 
Reported-by: Michal Hocko 
Acked-by: Michal Hocko 
Cc: Tejun Heo 
Cc: Hiroyuki Kamezawa 
Cc: Johannes Weiner 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

memcg: increment static branch right after limit set

2013-02-24T01:50:18+00:00

We were deferring the kmemcg static branch increment to a later time,
due to a nasty dependency between the cpu_hotplug lock, taken by the
jump label update, and the cgroup_lock.

Now we no longer take the cgroup lock, and we can save ourselves the
trouble.

Signed-off-by: Glauber Costa 
Acked-by: Michal Hocko 
Cc: Tejun Heo 
Cc: Hiroyuki Kamezawa 
Cc: Johannes Weiner 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

memcg: replace cgroup_lock with memcg specific memcg_lock

2013-02-24T01:50:18+00:00

After the preparation work done in earlier patches, the cgroup_lock can
be trivially replaced with a memcg-specific lock.  This is an automatic
translation at every site where the values involved were queried.

The sites where values are written, however, used to be naturally called
under cgroup_lock.  This is the case for instance in the css_online
callback.  For those, we now need to explicitly add the memcg lock.

With this, all the calls to cgroup_lock outside cgroup core are gone.

Signed-off-by: Glauber Costa 
Acked-by: Michal Hocko 
Cc: Tejun Heo 
Cc: Hiroyuki Kamezawa 
Cc: Johannes Weiner 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

memcg: fast hierarchy-aware child test

2013-02-24T01:50:18+00:00

Currently, we use cgroups' provided list of children to verify if it is
safe to proceed with any value change that is dependent on the cgroup
being empty.

This is less than ideal, because it enforces a dependency over cgroup
core that we would be better off without.  The solution proposed here is
to iterate over the child cgroups and if any is found that is already
online, we bounce and return: we don't really care how many children we
have, only if we have any.

This is also made to be hierarchy aware.  IOW, cgroups with hierarchy
disabled, while they still exist, will be considered for the purpose of
this interface as having no children.

[akpm@linux-foundation.org: tweak comments]
Signed-off-by: Glauber Costa 
Acked-by: Michal Hocko 
Cc: Tejun Heo 
Cc: Hiroyuki Kamezawa 
Cc: Johannes Weiner 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds