Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757091Ab2BXT1I (ORCPT ); Fri, 24 Feb 2012 14:27:08 -0500 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:54868 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754135Ab2BXT1H (ORCPT ); Fri, 24 Feb 2012 14:27:07 -0500 Message-ID: <4F47E47B.3000409@fb.com> Date: Fri, 24 Feb 2012 11:26:51 -0800 From: Arun Sharma User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.7; rv:10.0.2) Gecko/20120216 Thunderbird/10.0.2 MIME-Version: 1.0 To: KAMEZAWA Hiroyuki CC: Balbir Singh , , , Subject: Re: [PATCH] mm: Enable MAP_UNINITIALIZED for archs with mmu References: <1326912662-18805-1-git-send-email-asharma@fb.com> <4F468888.9090702@fb.com> <20120224114748.720ee79a.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20120224114748.720ee79a.kamezawa.hiroyu@jp.fujitsu.com> Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [192.168.18.252] X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:5.6.7498,1.0.260,0.0.0000 definitions=2012-02-24_06:2012-02-24,2012-02-24,1970-01-01 signatures=0 X-Proofpoint-Spam-Reason: safe Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1265 Lines: 31 On 2/23/12 6:47 PM, KAMEZAWA Hiroyuki wrote: >> >> 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 ? > From a security perspective or a resource limit perspective? Security: all processes in the cgroup run with the same uid and have the same access to the filesystem. Multiple address spaces in a cgroup can be thought of as an implementation detail. Resource limit: We don't have strict enforcement right now. There is a desire to include everything (file cache, slab memory) in the job's memory resource limit. -Arun -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/