Li Zefan wrote:
> Li Zefan 写道:
>> Balbir Singh wrote:
>>> A new configuration file called soft_limit_in_bytes is added. The parsing
>>> and configuration rules remain the same as for the limit_in_bytes user
>>> interface.
>>>
>>> A global list of all memory cgroups over their soft limit is maintained.
>>> This list is then used to reclaim memory on global pressure. A cgroup is
>>> removed from the list when the cgroup is deleted.
>>>
>>> The global list is protected with a read-write spinlock.
>>>
>> You are not using read-write spinlock..
>>
> 
> Ah, the spinlock is changed to r/w spinlock in [PATCH 3/4].
> 
>>> Signed-off-by: Balbir Singh <[EMAIL PROTECTED]>
>>> ---
>>>
>>>  mm/memcontrol.c |   33 ++++++++++++++++++++++++++++++++-
>>>  1 file changed, 32 insertions(+), 1 deletion(-)
>>>
>>> diff -puN mm/memcontrol.c~memory-controller-add-soft-limit-interface 
>>> mm/memcontrol.c
>>> --- 
>>> linux-2.6.25-rc2/mm/memcontrol.c~memory-controller-add-soft-limit-interface 
>>>     2008-02-19 12:31:49.000000000 +0530
>>> +++ linux-2.6.25-rc2-balbir/mm/memcontrol.c 2008-02-19 12:31:49.000000000 
>>> +0530
>>> @@ -35,6 +35,10 @@
>>>  
>>>  struct cgroup_subsys mem_cgroup_subsys;
>>>  static const int MEM_CGROUP_RECLAIM_RETRIES = 5;
>>> +static spinlock_t mem_cgroup_sl_list_lock; /* spin lock that protects */
>>> +                                           /* the list of cgroups over*/
>>> +                                           /* their soft limit */
>>> +static struct list_head mem_cgroup_sl_exceeded_list;
>>>  
>>>  /*
>>>   * Statistics for memory cgroup.
>>> @@ -136,6 +140,10 @@ struct mem_cgroup {
>>>      * statistics.
>>>      */
>>>     struct mem_cgroup_stat stat;
>>> +   /*
>>> +    * List of all mem_cgroup's that exceed their soft limit
>>> +    */
>>> +   struct list_head sl_exceeded_list;
>>>  };
>>>  
>>>  /*
>>> @@ -679,6 +687,18 @@ retry:
>>>             goto retry;
>>>     }
>>>  
>>> +   /*
>>> +    * If we exceed our soft limit, we get added to the list of
>>> +    * cgroups over their soft limit
>>> +    */
>>> +   if (!res_counter_check_under_limit(&mem->res, RES_SOFT_LIMIT)) {
>>> +           spin_lock_irqsave(&mem_cgroup_sl_list_lock, flags);
>>> +           if (list_empty(&mem->sl_exceeded_list))
>>> +                   list_add_tail(&mem->sl_exceeded_list,
>>> +                                           &mem_cgroup_sl_exceeded_list);
>>> +           spin_unlock_irqrestore(&mem_cgroup_sl_list_lock, flags);
>>> +   }
>>> +
>>>     mz = page_cgroup_zoneinfo(pc);
>>>     spin_lock_irqsave(&mz->lru_lock, flags);
>>>     /* Update statistics vector */
>>> @@ -736,13 +756,14 @@ void mem_cgroup_uncharge(struct page_cgr
>>>     if (atomic_dec_and_test(&pc->ref_cnt)) {
>>>             page = pc->page;
>>>             mz = page_cgroup_zoneinfo(pc);
>>> +           mem = pc->mem_cgroup;
>>>             /*
>>>              * get page->cgroup and clear it under lock.
>>>              * force_empty can drop page->cgroup without checking refcnt.
>>>              */
>>>             unlock_page_cgroup(page);
>>> +
>>>             if (clear_page_cgroup(page, pc) == pc) {
>>> -                   mem = pc->mem_cgroup;
>>>                     css_put(&mem->css);
>>>                     res_counter_uncharge(&mem->res, PAGE_SIZE);
>>>                     spin_lock_irqsave(&mz->lru_lock, flags);
>>> @@ -1046,6 +1067,12 @@ static struct cftype mem_cgroup_files[] 
>>>             .name = "stat",
>>>             .open = mem_control_stat_open,
>>>     },
>>> +   {
>>> +           .name = "soft_limit_in_bytes",
>>> +           .private = RES_SOFT_LIMIT,
>>> +           .write = mem_cgroup_write,
>>> +           .read = mem_cgroup_read,
>>> +   },
>>>  };
>>>  
>>>  static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
>>> @@ -1097,6 +1124,9 @@ mem_cgroup_create(struct cgroup_subsys *
>>>     if (unlikely((cont->parent) == NULL)) {
>>>             mem = &init_mem_cgroup;
>>>             init_mm.mem_cgroup = mem;
>>> +           INIT_LIST_HEAD(&mem->sl_exceeded_list);
>>> +           spin_lock_init(&mem_cgroup_sl_list_lock);
>>> +           INIT_LIST_HEAD(&mem_cgroup_sl_exceeded_list);
>>>     } else
>>>             mem = kzalloc(sizeof(struct mem_cgroup), GFP_KERNEL);
>>>  
>>> @@ -1104,6 +1134,7 @@ mem_cgroup_create(struct cgroup_subsys *
>>>             return NULL;
>>>  
>>>     res_counter_init(&mem->res);
>>> +   INIT_LIST_HEAD(&mem->sl_exceeded_list);
>>>  
>> mem->sl_exceeded_list initialized twice ?
>>

Good catch, yes for the root, it can be initialized twice. I'll fix it in v3.

>>>     memset(&mem->info, 0, sizeof(mem->info));
>>>  
>>> _
>>>
>> --


-- 
        Warm Regards,
        Balbir Singh
        Linux Technology Center
        IBM, ISTL

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