Re: [PATCH] mm: Enable MAP_UNINITIALIZED for archs with mmu

[KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>]

On Thu, 23 Feb 2012 10:42:16 -0800
Arun Sharma <asharma@fb.com> wrote:

> Hi Balbir,
> 
> Thanks for reviewing. Would you change your position if I limit the 
> scope of the patch to a cgroup with a single address space?
> 
> The moment the cgroup sees more than one address space (either due to 
> tasks getting created or being added), this optimization would be turned 
> off.
> 
> More details below:
> 
> On 2/22/12 11:45 PM, Balbir Singh wrote:
> >
> > So the assumption is that only apps that have access to each others
> > VMA's will run in this cgroup?
> >
> 
> In a distributed computing environment, a user submits a job to the 
> cluster job scheduler. The job might involve multiple related 
> executables and might involve multiple address spaces. But they're 
> performing one logical task, have a single resource limit enforced by a 
> cgroup.
> 
> They don't have access to each other's VMAs, but if "accidentally" one 
> of them comes across an uninitialized page with data from another task, 
> it's not a violation of the security model.
> 
How do you handle shared resouce, file-cache ?

Thanks,
-Kame

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