From: Johannes Weiner <han...@cmpxchg.org> Instead of returning NULL from try_get_mem_cgroup_from_mm() when the mm owner is exiting, just return root_mem_cgroup. This makes sense for all callsites and gets rid of some of them having to fallback manually.
[fengguang...@intel.com: fix warnings] Signed-off-by: Johannes Weiner <han...@cmpxchg.org> Signed-off-by: Fengguang Wu <fengguang...@intel.com> Acked-by: Michal Hocko <mho...@suse.cz> Signed-off-by: Andrew Morton <a...@linux-foundation.org> Signed-off-by: Linus Torvalds <torva...@linux-foundation.org> https://jira.sw.ru/browse/PSBM-51558 (cherry picked from commit df381975463996178d685f6ef7d3555c5f887201) Signed-off-by: Andrey Ryabinin <aryabi...@virtuozzo.com> --- include/linux/memcontrol.h | 12 ++++++------ mm/memcontrol.c | 37 +++++++++++++++++-------------------- mm/oom_kill.c | 4 ++-- net/packet/af_packet.c | 2 +- 4 files changed, 26 insertions(+), 29 deletions(-) diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index f1b599f..bcf7752 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -85,7 +85,7 @@ int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *memcg) extern struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page); extern struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p); -extern struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm); +extern struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm); extern struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *memcg); extern struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont); @@ -304,17 +304,17 @@ static inline struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page) return NULL; } -static inline struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm) -{ - return NULL; -} - static inline bool mm_match_cgroup(struct mm_struct *mm, struct mem_cgroup *memcg) { return true; } +static inline struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm) +{ + return NULL; +} + static inline int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *memcg) { diff --git a/mm/memcontrol.c b/mm/memcontrol.c index d09d55d9..40ac81b 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1166,15 +1166,24 @@ struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p) return mem_cgroup_from_css(task_subsys_state(p, mem_cgroup_subsys_id)); } -struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm) +struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm) { struct mem_cgroup *memcg = NULL; rcu_read_lock(); do { - memcg = mem_cgroup_from_task(rcu_dereference(mm->owner)); - if (unlikely(!memcg)) - break; + /* + * Page cache insertions can happen withou an + * actual mm context, e.g. during disk probing + * on boot, loopback IO, acct() writes etc. + */ + if (unlikely(!mm)) + memcg = root_mem_cgroup; + else { + memcg = mem_cgroup_from_task(rcu_dereference(mm->owner)); + if (unlikely(!memcg)) + memcg = root_mem_cgroup; + } } while (!css_tryget(&memcg->css)); rcu_read_unlock(); return memcg; @@ -1546,7 +1555,7 @@ int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *memcg) p = find_lock_task_mm(task); if (p) { - curr = try_get_mem_cgroup_from_mm(p->mm); + curr = get_mem_cgroup_from_mm(p->mm); task_unlock(p); } else { /* @@ -1560,8 +1569,6 @@ int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *memcg) css_get(&curr->css); task_unlock(task); } - if (!curr) - return 0; /* * We should check use_hierarchy of "memcg" not "curr". Because checking * use_hierarchy of "curr" here make this function true if hierarchy is @@ -1693,7 +1700,7 @@ void mem_cgroup_note_oom_kill(struct mem_cgroup *root_memcg, p = find_lock_task_mm(task); if (p) { - memcg = try_get_mem_cgroup_from_mm(p->mm); + memcg = get_mem_cgroup_from_mm(p->mm); task_unlock(p); } else { rcu_read_lock(); @@ -3458,9 +3465,7 @@ struct kmem_cache *__memcg_kmem_get_cache(struct kmem_cache *cachep, if (!current->mm || current->memcg_kmem_skip_account) return cachep; - memcg = try_get_mem_cgroup_from_mm(current->mm); - if (unlikely(!memcg)) - return cachep; + memcg = get_mem_cgroup_from_mm(current->mm); if (!memcg_kmem_is_active(memcg)) goto out; @@ -3543,15 +3548,7 @@ __memcg_kmem_newpage_charge(struct page *page, gfp_t gfp, int order) if (!current->mm || current->memcg_kmem_skip_account) return true; - memcg = try_get_mem_cgroup_from_mm(current->mm); - - /* - * very rare case described in mem_cgroup_from_task. Unfortunately there - * isn't much we can do without complicating this too much, and it would - * be gfp-dependent anyway. Just let it go - */ - if (unlikely(!memcg)) - return true; + memcg = get_mem_cgroup_from_mm(current->mm); if (!memcg_kmem_is_active(memcg)) { css_put(&memcg->css); diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 6b0542c2..a82433f 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -182,7 +182,7 @@ static unsigned long mm_overdraft(struct mm_struct *mm) struct oom_context *ctx; unsigned long overdraft; - memcg = try_get_mem_cgroup_from_mm(mm); + memcg = get_mem_cgroup_from_mm(mm); ctx = mem_cgroup_oom_context(memcg); overdraft = ctx->overdraft; if (memcg) @@ -476,7 +476,7 @@ void mark_oom_victim(struct task_struct *tsk) * owner memcg so that others can wait for it to exit. It will * be cleared in exit_oom_victim. */ - memcg = try_get_mem_cgroup_from_mm(tsk->mm); + memcg = get_mem_cgroup_from_mm(tsk->mm); ctx = mem_cgroup_oom_context(memcg); spin_lock(&oom_context_lock); if (!ctx->victim) { diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index f58fa90..c15e57a 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -2521,7 +2521,7 @@ static struct cg_proto *packet_sk_charge(void) goto out; err = 0; - psc->memcg = try_get_mem_cgroup_from_mm(current->mm); + psc->memcg = get_mem_cgroup_from_mm(current->mm); if (!psc->memcg) goto out_free_psc; if (!memcg_kmem_is_active(psc->memcg)) -- 2.10.2 _______________________________________________ Devel mailing list Devel@openvz.org https://lists.openvz.org/mailman/listinfo/devel
