Re: [PATCH v4 3/7] move memcg reclaimable page into tail of inactive list

[Minchan Kim]

Hi Balbir,

On Mon, Dec 6, 2010 at 12:34 PM, Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx> wrote:
> * MinChan Kim <minchan.kim@xxxxxxxxx> [2010-12-06 02:29:11]:
>
>> Golbal page reclaim moves reclaimalbe pages into inactive list
>
> Some typos here and Rik already pointed out some other changes.
>
>> to reclaim asap. This patch apply the rule in memcg.
>> It can help to prevent unnecessary working page eviction of memcg.
>>
>> Cc: Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx>
>> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
>> Cc: Rik van Riel <riel@xxxxxxxxxx>
>> Cc: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
>> Signed-off-by: Minchan Kim <minchan.kim@xxxxxxxxx>
>> ---
>>  include/linux/memcontrol.h |    6 ++++++
>>  mm/memcontrol.c            |   27 +++++++++++++++++++++++++++
>>  mm/swap.c                  |    3 ++-
>>  3 files changed, 35 insertions(+), 1 deletions(-)
>>
>> diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
>> index 067115c..8317f5c 100644
>> --- a/include/linux/memcontrol.h
>> +++ b/include/linux/memcontrol.h
>> @@ -62,6 +62,7 @@ extern int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
>>                                       gfp_t gfp_mask);
>>  extern void mem_cgroup_add_lru_list(struct page *page, enum lru_list lru);
>>  extern void mem_cgroup_del_lru_list(struct page *page, enum lru_list lru);
>> +extern void mem_cgroup_rotate_reclaimable_page(struct page *page);
>>  extern void mem_cgroup_rotate_lru_list(struct page *page, enum lru_list lru);
>>  extern void mem_cgroup_del_lru(struct page *page);
>>  extern void mem_cgroup_move_lists(struct page *page,
>> @@ -207,6 +208,11 @@ static inline void mem_cgroup_del_lru_list(struct page *page, int lru)
>>       return ;
>>  }
>>
>> +static inline inline void mem_cgroup_rotate_reclaimable_page(struct page *page)
>> +{
>> +     return ;
>> +}
>> +
>>  static inline void mem_cgroup_rotate_lru_list(struct page *page, int lru)
>>  {
>>       return ;
>> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
>> index 729beb7..f9435be 100644
>> --- a/mm/memcontrol.c
>> +++ b/mm/memcontrol.c
>> @@ -829,6 +829,33 @@ void mem_cgroup_del_lru(struct page *page)
>>       mem_cgroup_del_lru_list(page, page_lru(page));
>>  }
>>
>> +/*
>> + * Writeback is about to end against a page which has been marked for immediate
>> + * reclaim.  If it still appears to be reclaimable, move it to the tail of the
>> + * inactive list.
>> + */
>> +void mem_cgroup_rotate_reclaimable_page(struct page *page)
>> +{
>> +     struct mem_cgroup_per_zone *mz;
>> +     struct page_cgroup *pc;
>> +     enum lru_list lru = page_lru_base_type(page);
>> +
>> +     if (mem_cgroup_disabled())
>> +             return;
>> +
>> +     pc = lookup_page_cgroup(page);
>> +     /*
>> +      * Used bit is set without atomic ops but after smp_wmb().
>> +      * For making pc->mem_cgroup visible, insert smp_rmb() here.
>> +      */
>> +     smp_rmb();
>> +     /* unused or root page is not rotated. */
>> +     if (!PageCgroupUsed(pc) || mem_cgroup_is_root(pc->mem_cgroup))
>> +             return;
>> +     mz = page_cgroup_zoneinfo(pc);
>> +     list_move_tail(&pc->lru, &mz->lists[lru]);
>> +}
>> +
>>  void mem_cgroup_rotate_lru_list(struct page *page, enum lru_list lru)
>>  {
>>       struct mem_cgroup_per_zone *mz;
>> diff --git a/mm/swap.c b/mm/swap.c
>> index 1f36f6f..0fe98e7 100644
>> --- a/mm/swap.c
>> +++ b/mm/swap.c
>> @@ -122,8 +122,9 @@ static void pagevec_move_tail(struct pagevec *pvec)
>>               }
>>               if (PageLRU(page) && !PageActive(page) &&
>>                                       !PageUnevictable(page)) {
>> -                     int lru = page_lru_base_type(page);
>> +                     enum lru_list lru = page_lru_base_type(page);
>>                       list_move_tail(&page->lru, &zone->lru[lru].list);
>> +                     mem_cgroup_rotate_reclaimable_page(page);
>>                       pgmoved++;
>>               }
>>       }
>
> Looks good, do you have any numbers, workloads that benefit? I agree
> that keeping both global and memcg reclaim in sync is a good idea.

This patch series for Ben's fadvise problem in rsync.
As I fix the global reclaim, I found this patch could help memcg, too.
If Ben is busy, I will measure the benefit.

>
> Acked-by: Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx>

Thanks, Balbir.

>
>
> --
>        Three Cheers,
>        Balbir
>



-- 
Kind regards,
Minchan Kim
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