[PATCH] memcg: Do not open code accesses to res_counter members

[PATCH] memcg: Do not open code accesses to res_counter members

[Glauber Costa]

We should use the acessor res_counter_read_u64 for that.
Although a purely cosmetic change is sometimes better of delayed,
to avoid conflicting with other people's work, we are starting to
have people touching this code as well, and reproducing the open
code behavior because that's the standard =)

Time to fix it, then.

Signed-off-by: Glauber Costa <glommer@parallels.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
---
 mm/memcontrol.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 87a1e21..27c1bfa 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3708,7 +3708,7 @@ move_account:
 			goto try_to_free;
 		cond_resched();
 	/* "ret" should also be checked to ensure all lists are empty. */
-	} while (memcg->res.usage > 0 || ret);
+	} while (res_counter_read_u64(&memcg->res, RES_USAGE) > 0 || ret);
 out:
 	css_put(&memcg->css);
 	return ret;
@@ -3723,7 +3723,7 @@ try_to_free:
 	lru_add_drain_all();
 	/* try to free all pages in this cgroup */
 	shrink = 1;
-	while (nr_retries && memcg->res.usage > 0) {
+	while (nr_retries && res_counter_read_u64(&memcg->res, RES_USAGE) > 0) {
 		int progress;
 
 		if (signal_pending(current)) {
-- 
1.7.7.6

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Re: [PATCH] memcg: Do not open code accesses to res_counter members

[KAMEZAWA Hiroyuki]

(2012/03/21 1:53), Glauber Costa wrote:

> We should use the acessor res_counter_read_u64 for that.
> Although a purely cosmetic change is sometimes better of delayed,
> to avoid conflicting with other people's work, we are starting to
> have people touching this code as well, and reproducing the open
> code behavior because that's the standard =)
> 
> Time to fix it, then.
> 
> Signed-off-by: Glauber Costa <glommer@parallels.com>
> Cc: Johannes Weiner <hannes@cmpxchg.org>
> Cc: Michal Hocko <mhocko@suse.cz>
> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>


Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>

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Re: [PATCH] memcg: Do not open code accesses to res_counter members

[Michal Hocko]

On Tue 20-03-12 20:53:44, Glauber Costa wrote:
> We should use the acessor res_counter_read_u64 for that.
> Although a purely cosmetic change is sometimes better of delayed,
> to avoid conflicting with other people's work, we are starting to
> have people touching this code as well, and reproducing the open
> code behavior because that's the standard =)
> 
> Time to fix it, then.

Looks good to me
Acked-by: Michal Hocko <mhocko@suse.cz>

Thanks
> 
> Signed-off-by: Glauber Costa <glommer@parallels.com>
> Cc: Johannes Weiner <hannes@cmpxchg.org>
> Cc: Michal Hocko <mhocko@suse.cz>
> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
> ---
>  mm/memcontrol.c |    4 ++--
>  1 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 87a1e21..27c1bfa 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -3708,7 +3708,7 @@ move_account:
>  			goto try_to_free;
>  		cond_resched();
>  	/* "ret" should also be checked to ensure all lists are empty. */
> -	} while (memcg->res.usage > 0 || ret);
> +	} while (res_counter_read_u64(&memcg->res, RES_USAGE) > 0 || ret);
>  out:
>  	css_put(&memcg->css);
>  	return ret;
> @@ -3723,7 +3723,7 @@ try_to_free:
>  	lru_add_drain_all();
>  	/* try to free all pages in this cgroup */
>  	shrink = 1;
> -	while (nr_retries && memcg->res.usage > 0) {
> +	while (nr_retries && res_counter_read_u64(&memcg->res, RES_USAGE) > 0) {
>  		int progress;
>  
>  		if (signal_pending(current)) {
> -- 
> 1.7.7.6
> 
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-- 
Michal Hocko
SUSE Labs
SUSE LINUX s.r.o.
Lihovarska 1060/12
190 00 Praha 9    
Czech Republic

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Re: [PATCH] memcg: Do not open code accesses to res_counter members

[Andrew Morton]

On Tue, 20 Mar 2012 20:53:44 +0400
Glauber Costa <glommer@parallels.com> wrote:

> We should use the acessor res_counter_read_u64 for that.
> Although a purely cosmetic change is sometimes better of delayed,
> to avoid conflicting with other people's work, we are starting to
> have people touching this code as well, and reproducing the open
> code behavior because that's the standard =)
> 
> ...
>
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -3708,7 +3708,7 @@ move_account:
>  			goto try_to_free;
>  		cond_resched();
>  	/* "ret" should also be checked to ensure all lists are empty. */
> -	} while (memcg->res.usage > 0 || ret);
> +	} while (res_counter_read_u64(&memcg->res, RES_USAGE) > 0 || ret);
>  out:
>  	css_put(&memcg->css);
>  	return ret;
> @@ -3723,7 +3723,7 @@ try_to_free:
>  	lru_add_drain_all();
>  	/* try to free all pages in this cgroup */
>  	shrink = 1;
> -	while (nr_retries && memcg->res.usage > 0) {
> +	while (nr_retries && res_counter_read_u64(&memcg->res, RES_USAGE) > 0) {
>  		int progress;
>  
>  		if (signal_pending(current)) {

Actually this fixes bugs on 32-bit machines.  Good luck trying to
demonstrate them at runtime though ;)

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