Hi Kame,
On Tue, May 14, 2013 at 8:15 AM, Kamezawa Hiroyuki
<kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote:
> (2013/05/13 14:05), Sha Zhengju wrote:
>> From: Sha Zhengju <handai.szj@xxxxxxxxxx>
>>
>> Change the first argument of mem_cgroup_{update,inc,dec}_page_stat() from
>> 'struct page *' to 'struct mem_cgroup *', and so move PageCgroupUsed(pc)
>> checking out of mem_cgroup_update_page_stat(). This is a prepare patch for
>> the following memcg page stat lock simplifying.
>>
>> Signed-off-by: Sha Zhengju <handai.szj@xxxxxxxxxx>
>
> Why we need to find page_cgroup and memcg and check pc->flags bit
> even if memcg is unused ? I think it's too slow.
>
> Sorry, NAK.
Yeah, it's my fault... my brain filter the !CONFIG_MEMCG automatically.
Sorry for the stupid mistake and thank you for reviewing!
Thanks,
Sha
>
>
>
>> ---
>> include/linux/memcontrol.h | 14 +++++++-------
>> mm/memcontrol.c | 9 ++-------
>> mm/rmap.c | 28 +++++++++++++++++++++++++---
>> 3 files changed, 34 insertions(+), 17 deletions(-)
>>
>> diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
>> index d6183f0..7af3ed3 100644
>> --- a/include/linux/memcontrol.h
>> +++ b/include/linux/memcontrol.h
>> @@ -163,20 +163,20 @@ static inline void mem_cgroup_end_update_page_stat(struct page *page,
>> rcu_read_unlock();
>> }
>>
>> -void mem_cgroup_update_page_stat(struct page *page,
>> +void mem_cgroup_update_page_stat(struct mem_cgroup *memcg,
>> enum mem_cgroup_page_stat_item idx,
>> int val);
>>
>> -static inline void mem_cgroup_inc_page_stat(struct page *page,
>> +static inline void mem_cgroup_inc_page_stat(struct mem_cgroup *memcg,
>> enum mem_cgroup_page_stat_item idx)
>> {
>> - mem_cgroup_update_page_stat(page, idx, 1);
>> + mem_cgroup_update_page_stat(memcg, idx, 1);
>> }
>>
>> -static inline void mem_cgroup_dec_page_stat(struct page *page,
>> +static inline void mem_cgroup_dec_page_stat(struct mem_cgroup *memcg,
>> enum mem_cgroup_page_stat_item idx)
>> {
>> - mem_cgroup_update_page_stat(page, idx, -1);
>> + mem_cgroup_update_page_stat(memcg, idx, -1);
>> }
>>
>> unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
>> @@ -347,12 +347,12 @@ static inline void mem_cgroup_end_update_page_stat(struct page *page,
>> {
>> }
>>
>> -static inline void mem_cgroup_inc_page_stat(struct page *page,
>> +static inline void mem_cgroup_inc_page_stat(struct mem_cgroup *memcg,
>> enum mem_cgroup_page_stat_item idx)
>> {
>> }
>>
>> -static inline void mem_cgroup_dec_page_stat(struct page *page,
>> +static inline void mem_cgroup_dec_page_stat(struct mem_cgroup *memcg,
>> enum mem_cgroup_page_stat_item idx)
>> {
>> }
>> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
>> index b31513e..a394ba4 100644
>> --- a/mm/memcontrol.c
>> +++ b/mm/memcontrol.c
>> @@ -2367,18 +2367,13 @@ void __mem_cgroup_end_update_page_stat(struct page *page, unsigned long *flags)
>> move_unlock_mem_cgroup(pc->mem_cgroup, flags);
>> }
>>
>> -void mem_cgroup_update_page_stat(struct page *page,
>> +void mem_cgroup_update_page_stat(struct mem_cgroup *memcg,
>> enum mem_cgroup_page_stat_item idx, int val)
>> {
>> - struct mem_cgroup *memcg;
>> - struct page_cgroup *pc = lookup_page_cgroup(page);
>> - unsigned long uninitialized_var(flags);
>> -
>> if (mem_cgroup_disabled())
>> return;
>>
>> - memcg = pc->mem_cgroup;
>> - if (unlikely(!memcg || !PageCgroupUsed(pc)))
>> + if (unlikely(!memcg))
>> return;
>>
>> switch (idx) {
>> diff --git a/mm/rmap.c b/mm/rmap.c
>> index 6280da8..a03c2a9 100644
>> --- a/mm/rmap.c
>> +++ b/mm/rmap.c
>> @@ -1109,12 +1109,24 @@ void page_add_file_rmap(struct page *page)
>> {
>> bool locked;
>> unsigned long flags;
>> + struct page_cgroup *pc;
>> + struct mem_cgroup *memcg = NULL;
>>
>> mem_cgroup_begin_update_page_stat(page, &locked, &flags);
>> + pc = lookup_page_cgroup(page);
>> +
>> + rcu_read_lock();
>> + memcg = pc->mem_cgroup;
>> + if (unlikely(!PageCgroupUsed(pc)))
>> + memcg = NULL;
>> +
>> if (atomic_inc_and_test(&page->_mapcount)) {
>> __inc_zone_page_state(page, NR_FILE_MAPPED);
>> - mem_cgroup_inc_page_stat(page, MEMCG_NR_FILE_MAPPED);
>> + if (memcg)
>> + mem_cgroup_inc_page_stat(memcg, MEMCG_NR_FILE_MAPPED);
>> }
>> + rcu_read_unlock();
>> +
>> mem_cgroup_end_update_page_stat(page, &locked, &flags);
>> }
>>
>> @@ -1129,14 +1141,22 @@ void page_remove_rmap(struct page *page)
>> bool anon = PageAnon(page);
>> bool locked;
>> unsigned long flags;
>> + struct page_cgroup *pc;
>> + struct mem_cgroup *memcg = NULL;
>>
>> /*
>> * The anon case has no mem_cgroup page_stat to update; but may
>> * uncharge_page() below, where the lock ordering can deadlock if
>> * we hold the lock against page_stat move: so avoid it on anon.
>> */
>> - if (!anon)
>> + if (!anon) {
>> mem_cgroup_begin_update_page_stat(page, &locked, &flags);
>> + pc = lookup_page_cgroup(page);
>> + rcu_read_lock();
>> + memcg = pc->mem_cgroup;
>> + if (unlikely(!PageCgroupUsed(pc)))
>> + memcg = NULL;
>> + }
>>
>> /* page still mapped by someone else? */
>> if (!atomic_add_negative(-1, &page->_mapcount))
>> @@ -1157,7 +1177,9 @@ void page_remove_rmap(struct page *page)
>> NR_ANON_TRANSPARENT_HUGEPAGES);
>> } else {
>> __dec_zone_page_state(page, NR_FILE_MAPPED);
>> - mem_cgroup_dec_page_stat(page, MEMCG_NR_FILE_MAPPED);
>> + if (memcg)
>> + mem_cgroup_dec_page_stat(memcg, MEMCG_NR_FILE_MAPPED);
>> + rcu_read_unlock();
>> mem_cgroup_end_update_page_stat(page, &locked, &flags);
>> }
>> if (unlikely(PageMlocked(page)))
>>
>
>
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>