Re: [RFC][PATCH 1/7][memcg] virtually indexed array library.

From: Balbir Singh
Date: Mon Aug 02 2010 - 14:01:03 EST


* KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> [2010-07-29 13:27:03]:

> On Thu, 29 Jul 2010 09:32:26 +0900
> KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote:
>
> > On Wed, 28 Jul 2010 12:45:13 -0700
> > Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
>
> > > My gut reaction to this sort of thing is "run away in terror". It
> > > encourages kernel developers to operate like lackadaisical userspace
> > > developers and to assume that underlying code can perform heroic and
> > > immortal feats. But it can't. This is the kernel and the kernel is a
> > > tough and hostile place and callers should be careful and defensive and
> > > take great efforts to minimise the strain they put upon other systems.
> > >
> > > IOW, can we avoid doing this?
> > >
> >
>
> I'll use pre-allocated pointer array in the next version. It's simple even
> if a bit slow.
>
> ==
> struct mem_cgroup *mem_cgroups[CONFIG_MAX_MEM_CGROUPS] __read_mostly;
> #define id_to_memcg(id) mem_cgroups[id];
> ==

Hmm.. I thought we were going to reuse css_id() and use that to get to
the cgroup. May be I am missing something.


--
Three Cheers,
Balbir
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