diff options
author | Simon Horman <horms@verge.net.au> | 2008-10-07 08:40:11 +1100 |
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committer | Simon Horman <horms@verge.net.au> | 2008-10-07 08:40:11 +1100 |
commit | a5e8546a8bff5d2047adc279df5753c44ba7b1a1 (patch) | |
tree | d9ca91f74d8279adbb1d3e942cc7ab145780ee29 /mm/memcontrol.c | |
parent | cb7f6a7b716e801097b564dec3ccb58d330aef56 (diff) | |
parent | c7004482e8dcb7c3c72666395cfa98a216a4fb70 (diff) |
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next-2.6 into lvs-next-2.6
Diffstat (limited to 'mm/memcontrol.c')
-rw-r--r-- | mm/memcontrol.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 0f1f7a7374b..36896f3eb7f 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -250,6 +250,14 @@ static struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont) struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p) { + /* + * mm_update_next_owner() may clear mm->owner to NULL + * if it races with swapoff, page migration, etc. + * So this can be called with p == NULL. + */ + if (unlikely(!p)) + return NULL; + return container_of(task_subsys_state(p, mem_cgroup_subsys_id), struct mem_cgroup, css); } @@ -549,6 +557,11 @@ static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm, if (likely(!memcg)) { rcu_read_lock(); mem = mem_cgroup_from_task(rcu_dereference(mm->owner)); + if (unlikely(!mem)) { + rcu_read_unlock(); + kmem_cache_free(page_cgroup_cache, pc); + return 0; + } /* * For every charge from the cgroup, increment reference count */ @@ -801,11 +814,16 @@ int mem_cgroup_shrink_usage(struct mm_struct *mm, gfp_t gfp_mask) rcu_read_lock(); mem = mem_cgroup_from_task(rcu_dereference(mm->owner)); + if (unlikely(!mem)) { + rcu_read_unlock(); + return 0; + } css_get(&mem->css); rcu_read_unlock(); do { progress = try_to_free_mem_cgroup_pages(mem, gfp_mask); + progress += res_counter_check_under_limit(&mem->res); } while (!progress && --retry); css_put(&mem->css); |