linux-kernel - Re: [PATCH v5 09/14] memcg: kmem accounting lifecycle management

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <alpine.DEB.2.00.1210171624540.20813@chino.kir.corp.google.com>
Date:	Wed, 17 Oct 2012 16:28:38 -0700 (PDT)
From:	David Rientjes <rientjes@...gle.com>
To:	Glauber Costa <glommer@...allels.com>
cc:	linux-mm@...ck.org, cgroups@...r.kernel.org,
	Mel Gorman <mgorman@...e.de>, Tejun Heo <tj@...nel.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Michal Hocko <mhocko@...e.cz>,
	Johannes Weiner <hannes@...xchg.org>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>,
	Christoph Lameter <cl@...ux.com>,
	Pekka Enberg <penberg@...nel.org>, devel@...nvz.org,
	linux-kernel@...r.kernel.org,
	Pekka Enberg <penberg@...helsinki.fi>,
	Suleiman Souhlal <suleiman@...gle.com>
Subject: Re: [PATCH v5 09/14] memcg: kmem accounting lifecycle management

On Tue, 16 Oct 2012, Glauber Costa wrote:

> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 1182188..e24b388 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -344,6 +344,7 @@ struct mem_cgroup {
>  /* internal only representation about the status of kmem accounting. */
>  enum {
>  	KMEM_ACCOUNTED_ACTIVE = 0, /* accounted by this cgroup itself */
> +	KMEM_ACCOUNTED_DEAD, /* dead memcg, pending kmem charges */

"dead memcg with pending kmem charges" seems better.

>  };
>  
>  #define KMEM_ACCOUNTED_MASK (1 << KMEM_ACCOUNTED_ACTIVE)
> @@ -353,6 +354,22 @@ static void memcg_kmem_set_active(struct mem_cgroup *memcg)
>  {
>  	set_bit(KMEM_ACCOUNTED_ACTIVE, &memcg->kmem_accounted);
>  }
> +
> +static bool memcg_kmem_is_active(struct mem_cgroup *memcg)
> +{
> +	return test_bit(KMEM_ACCOUNTED_ACTIVE, &memcg->kmem_accounted);
> +}

I think all of these should be inline.

> +
> +static void memcg_kmem_mark_dead(struct mem_cgroup *memcg)
> +{
> +	if (test_bit(KMEM_ACCOUNTED_ACTIVE, &memcg->kmem_accounted))
> +		set_bit(KMEM_ACCOUNTED_DEAD, &memcg->kmem_accounted);
> +}

The set_bit() doesn't happen atomically with the test_bit(), what 
synchronization is required for this?
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/