On Wed, Dec 7, 2011 at 7:03 PM, KAMEZAWA Hiroyuki
<kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote:
> On Wed, 7 Dec 2011 18:30:46 +0800
> Bob Liu <lliubbo@xxxxxxxxx> wrote:
>
>> uncharge will happen only when !page_mapped(page) no matter MEM_CGROUP_CHARGE_TYPE_DROP
>> or MEM_CGROUP_CHARGE_TYPE_SWAPOUT when called from mem_cgroup_uncharge_swapcache().
>> i think it's no difference, so drop it.
>>
>> Signed-off-by: Bob Liu <lliubbo@xxxxxxxxx>
>
> I think you didn't test at all.
>
>> ---
>> mm/memcontrol.c | 5 -----
>> 1 files changed, 0 insertions(+), 5 deletions(-)
>>
>> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
>> index 6aff93c..02a2988 100644
>> --- a/mm/memcontrol.c
>> +++ b/mm/memcontrol.c
>> @@ -339,7 +339,6 @@ enum charge_type {
>> MEM_CGROUP_CHARGE_TYPE_SHMEM, /* used by page migration of shmem */
>> MEM_CGROUP_CHARGE_TYPE_FORCE, /* used by force_empty */
>> MEM_CGROUP_CHARGE_TYPE_SWAPOUT, /* for accounting swapcache */
>> - MEM_CGROUP_CHARGE_TYPE_DROP, /* a page was unused swap cache */
>> NR_CHARGE_TYPE,
>> };
>>
>> @@ -3000,7 +2999,6 @@ __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
>>
>> switch (ctype) {
>> case MEM_CGROUP_CHARGE_TYPE_MAPPED:
>> - case MEM_CGROUP_CHARGE_TYPE_DROP:
>> /* See mem_cgroup_prepare_migration() */
>> if (page_mapped(page) || PageCgroupMigration(pc))
>> goto unlock_out;
>> @@ -3121,9 +3119,6 @@ mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout)
>> struct mem_cgroup *memcg;
>> int ctype = MEM_CGROUP_CHARGE_TYPE_SWAPOUT;
>>
>> - if (!swapout) /* this was a swap cache but the swap is unused ! */
>> - ctype = MEM_CGROUP_CHARGE_TYPE_DROP;
>> -
>
> Then, here , what ctype must be if !swapout ?
>
I think MEM_CGROUP_CHARGE_TYPE_SWAPOUT is okay, i didn't get the point
that the benefit of using MEM_CGROUP_CHARGE_TYPE_DROP.
If use MEM_CGROUP_CHARGE_TYPE_SWAPOUT, page_mapped(page) also checked in
__mem_cgroup_uncharge_common().
Maybe i missed something. Thanks.
3003 case MEM_CGROUP_CHARGE_TYPE_DROP:
3004 /* See mem_cgroup_prepare_migration() */
3005 if (page_mapped(page) || PageCgroupMigration(pc))
3006 goto unlock_out;
3007 break;
3008 case MEM_CGROUP_CHARGE_TYPE_SWAPOUT:
3009 if (!PageAnon(page)) { /* Shared memory */
3010 if (page->mapping && !page_is_file_cache(page))
3011 goto unlock_out;
3012 } else if (page_mapped(page)) /* Anon */
3013 goto unlock_out;
3014 break;
> Nack.
>
> Thanks,
> -Kame
>
--
Regards,
--Bob
--
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