diff options
author | Haavard Skinnemoen <haavard.skinnemoen@atmel.com> | 2008-10-12 15:44:33 +0200 |
---|---|---|
committer | Haavard Skinnemoen <haavard.skinnemoen@atmel.com> | 2008-10-12 15:44:33 +0200 |
commit | 0d62950125241a6e6db8e8f14271f098ec7a2da4 (patch) | |
tree | 8cdd9e17f6a6ff4cb6166ad12a4d3ed1d45b2dc9 /mm/memcontrol.c | |
parent | b3bc2c5562f06ca34b30f61c5714e96490946c81 (diff) | |
parent | 5e7184ae0dd49456387e8b1cdebc6b2c92fc6d51 (diff) |
Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/hskinnemoen/atmel-mci-2.6.28
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); |