diff options
Diffstat (limited to 'mm/memcontrol.c')
| -rw-r--r-- | mm/memcontrol.c | 41 |
1 files changed, 27 insertions, 14 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index f7a552eb3e9d..8f3244e59b30 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -897,13 +897,24 @@ struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p) } EXPORT_SYMBOL(mem_cgroup_from_task); +static __always_inline struct mem_cgroup *active_memcg(void) +{ + if (in_interrupt()) + return this_cpu_read(int_active_memcg); + else + return current->active_memcg; +} + /** * get_mem_cgroup_from_mm: Obtain a reference on given mm_struct's memcg. * @mm: mm from which memcg should be extracted. It can be NULL. * - * Obtain a reference on mm->memcg and returns it if successful. Otherwise - * root_mem_cgroup is returned. However if mem_cgroup is disabled, NULL is - * returned. + * Obtain a reference on mm->memcg and returns it if successful. If mm + * is NULL, then the memcg is chosen as follows: + * 1) The active memcg, if set. + * 2) current->mm->memcg, if available + * 3) root memcg + * If mem_cgroup is disabled, NULL is returned. */ struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm) { @@ -921,8 +932,17 @@ struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm) * counting is disabled on the root level in the * cgroup core. See CSS_NO_REF. */ - if (unlikely(!mm)) - return root_mem_cgroup; + if (unlikely(!mm)) { + memcg = active_memcg(); + if (unlikely(memcg)) { + /* remote memcg must hold a ref */ + css_get(&memcg->css); + return memcg; + } + mm = current->mm; + if (unlikely(!mm)) + return root_mem_cgroup; + } rcu_read_lock(); do { @@ -935,14 +955,6 @@ struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm) } EXPORT_SYMBOL(get_mem_cgroup_from_mm); -static __always_inline struct mem_cgroup *active_memcg(void) -{ - if (in_interrupt()) - return this_cpu_read(int_active_memcg); - else - return current->active_memcg; -} - static __always_inline bool memcg_kmem_bypass(void) { /* Allow remote memcg charging from any context. */ @@ -6711,7 +6723,8 @@ out: * @gfp_mask: reclaim mode * * Try to charge @page to the memcg that @mm belongs to, reclaiming - * pages according to @gfp_mask if necessary. + * pages according to @gfp_mask if necessary. if @mm is NULL, try to + * charge to the active memcg. * * Do not use this for pages allocated for swapin. * |