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* [PATCH] memcg: drop type MEM_CGROUP_CHARGE_TYPE_DROP
@ 2011-12-07 10:30 Bob Liu
  2011-12-07 11:03 ` KAMEZAWA Hiroyuki
  2011-12-07 14:22 ` Johannes Weiner
  0 siblings, 2 replies; 6+ messages in thread
From: Bob Liu @ 2011-12-07 10:30 UTC (permalink / raw)
  To: linux-mm; +Cc: akpm, kamezawa.hiroyu, jweiner, mhocko, Bob Liu

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@gmail.com>
---
 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;
-
 	memcg = __mem_cgroup_uncharge_common(page, ctype);
 
 	/*
-- 
1.7.0.4


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^ permalink raw reply related	[flat|nested] 6+ messages in thread

* Re: [PATCH] memcg: drop type MEM_CGROUP_CHARGE_TYPE_DROP
  2011-12-07 10:30 [PATCH] memcg: drop type MEM_CGROUP_CHARGE_TYPE_DROP Bob Liu
@ 2011-12-07 11:03 ` KAMEZAWA Hiroyuki
  2011-12-07 12:29   ` Bob Liu
  2011-12-07 14:22 ` Johannes Weiner
  1 sibling, 1 reply; 6+ messages in thread
From: KAMEZAWA Hiroyuki @ 2011-12-07 11:03 UTC (permalink / raw)
  To: Bob Liu; +Cc: linux-mm, akpm, jweiner, mhocko

On Wed, 7 Dec 2011 18:30:46 +0800
Bob Liu <lliubbo@gmail.com> 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@gmail.com>

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 ?

Nack.

Thanks,
-Kame

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^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] memcg: drop type MEM_CGROUP_CHARGE_TYPE_DROP
  2011-12-07 11:03 ` KAMEZAWA Hiroyuki
@ 2011-12-07 12:29   ` Bob Liu
  2011-12-08  1:42     ` KAMEZAWA Hiroyuki
  0 siblings, 1 reply; 6+ messages in thread
From: Bob Liu @ 2011-12-07 12:29 UTC (permalink / raw)
  To: KAMEZAWA Hiroyuki; +Cc: linux-mm, akpm, jweiner, mhocko

On Wed, Dec 7, 2011 at 7:03 PM, KAMEZAWA Hiroyuki
<kamezawa.hiroyu@jp.fujitsu.com> wrote:
> On Wed, 7 Dec 2011 18:30:46 +0800
> Bob Liu <lliubbo@gmail.com> 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@gmail.com>
>
> 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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^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] memcg: drop type MEM_CGROUP_CHARGE_TYPE_DROP
  2011-12-07 10:30 [PATCH] memcg: drop type MEM_CGROUP_CHARGE_TYPE_DROP Bob Liu
  2011-12-07 11:03 ` KAMEZAWA Hiroyuki
@ 2011-12-07 14:22 ` Johannes Weiner
  1 sibling, 0 replies; 6+ messages in thread
From: Johannes Weiner @ 2011-12-07 14:22 UTC (permalink / raw)
  To: Bob Liu; +Cc: linux-mm, akpm, kamezawa.hiroyu, mhocko

On Wed, Dec 07, 2011 at 06:30:46PM +0800, Bob Liu 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@gmail.com>
> ---
>  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;
> -

Pages are in swap cache for swapping in as well as for swapping out.
When a page is removed from swap cache and memory, the accounting
needs to know about the direction.  See the other checks against
TYPE_SWAPOUT.

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^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] memcg: drop type MEM_CGROUP_CHARGE_TYPE_DROP
  2011-12-07 12:29   ` Bob Liu
@ 2011-12-08  1:42     ` KAMEZAWA Hiroyuki
  2011-12-08 10:34       ` Bob Liu
  0 siblings, 1 reply; 6+ messages in thread
From: KAMEZAWA Hiroyuki @ 2011-12-08  1:42 UTC (permalink / raw)
  To: Bob Liu; +Cc: linux-mm, akpm, jweiner, mhocko

On Wed, 7 Dec 2011 20:29:24 +0800
Bob Liu <lliubbo@gmail.com> wrote:

> On Wed, Dec 7, 2011 at 7:03 PM, KAMEZAWA Hiroyuki
> <kamezawa.hiroyu@jp.fujitsu.com> wrote:
> > On Wed, 7 Dec 2011 18:30:46 +0800
> > Bob Liu <lliubbo@gmail.com> 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@gmail.com>
> >
> > I think you didn't test at all.
> >
> >> ---
> >> A mm/memcontrol.c | A  A 5 -----
> >> A 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 {
> >> A  A  A  MEM_CGROUP_CHARGE_TYPE_SHMEM, A  /* used by page migration of shmem */
> >> A  A  A  MEM_CGROUP_CHARGE_TYPE_FORCE, A  /* used by force_empty */
> >> A  A  A  MEM_CGROUP_CHARGE_TYPE_SWAPOUT, /* for accounting swapcache */
> >> - A  A  MEM_CGROUP_CHARGE_TYPE_DROP, A  A /* a page was unused swap cache */
> >> A  A  A  NR_CHARGE_TYPE,
> >> A };
> >>
> >> @@ -3000,7 +2999,6 @@ __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
> >>
> >> A  A  A  switch (ctype) {
> >> A  A  A  case MEM_CGROUP_CHARGE_TYPE_MAPPED:
> >> - A  A  case MEM_CGROUP_CHARGE_TYPE_DROP:
> >> A  A  A  A  A  A  A  /* See mem_cgroup_prepare_migration() */
> >> A  A  A  A  A  A  A  if (page_mapped(page) || PageCgroupMigration(pc))
> >> A  A  A  A  A  A  A  A  A  A  A  goto unlock_out;
> >> @@ -3121,9 +3119,6 @@ mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout)
> >> A  A  A  struct mem_cgroup *memcg;
> >> A  A  A  int ctype = MEM_CGROUP_CHARGE_TYPE_SWAPOUT;
> >>
> >> - A  A  if (!swapout) /* this was a swap cache but the swap is unused ! */
> >> - A  A  A  A  A  A  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.
> 
why you don't see 10 more lines.

If SWAPOUT, 
  - record swap out information to swap_cgroup
  - don't decrease memcg->memsw counter
If DROP
  - same as usual MAPPED anon pages.

DROP may be equal to MAPPED. But this swap realted codes are most fragile
part of memcg and we used another name than MAPPED for taking care.

Thanks,
-Kame

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^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] memcg: drop type MEM_CGROUP_CHARGE_TYPE_DROP
  2011-12-08  1:42     ` KAMEZAWA Hiroyuki
@ 2011-12-08 10:34       ` Bob Liu
  0 siblings, 0 replies; 6+ messages in thread
From: Bob Liu @ 2011-12-08 10:34 UTC (permalink / raw)
  To: KAMEZAWA Hiroyuki; +Cc: linux-mm, akpm, jweiner, mhocko

On Thu, Dec 8, 2011 at 9:42 AM, KAMEZAWA Hiroyuki
<kamezawa.hiroyu@jp.fujitsu.com> wrote:
> On Wed, 7 Dec 2011 20:29:24 +0800
> Bob Liu <lliubbo@gmail.com> wrote:
>
>> On Wed, Dec 7, 2011 at 7:03 PM, KAMEZAWA Hiroyuki
>> <kamezawa.hiroyu@jp.fujitsu.com> wrote:
>> > On Wed, 7 Dec 2011 18:30:46 +0800
>> > Bob Liu <lliubbo@gmail.com> 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@gmail.com>
>> >
>> > 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.
>>
> why you don't see 10 more lines.
>
> If SWAPOUT,
>  - record swap out information to swap_cgroup
>  - don't decrease memcg->memsw counter
> If DROP
>  - same as usual MAPPED anon pages.
>
> DROP may be equal to MAPPED. But this swap realted codes are most fragile
> part of memcg and we used another name than MAPPED for taking care.
>

Get it.
Sorry for my noise, i didn't deep into following function.

-- 
Regards,
--Bob

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^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2011-12-08 10:34 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2011-12-07 10:30 [PATCH] memcg: drop type MEM_CGROUP_CHARGE_TYPE_DROP Bob Liu
2011-12-07 11:03 ` KAMEZAWA Hiroyuki
2011-12-07 12:29   ` Bob Liu
2011-12-08  1:42     ` KAMEZAWA Hiroyuki
2011-12-08 10:34       ` Bob Liu
2011-12-07 14:22 ` Johannes Weiner

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