Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758902AbXF0DDq (ORCPT ); Tue, 26 Jun 2007 23:03:46 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754232AbXF0DDj (ORCPT ); Tue, 26 Jun 2007 23:03:39 -0400 Received: from mx1.redhat.com ([66.187.233.31]:53959 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754011AbXF0DDi (ORCPT ); Tue, 26 Jun 2007 23:03:38 -0400 Message-ID: <4681D37E.2020706@redhat.com> Date: Tue, 26 Jun 2007 23:03:26 -0400 From: Rik van Riel Organization: Red Hat, Inc User-Agent: Thunderbird 1.5.0.7 (X11/20061008) MIME-Version: 1.0 To: Davide Libenzi CC: Linux Kernel Mailing List Subject: Re: [patch 1/3] MAP_NOZERO - implement a new VM_NOZERO/MAP_NOZERO page retirement policy References: In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1677 Lines: 42 Davide Libenzi wrote: > This is the core implementation of the new VM_NOZERO page retirement > policy (and the associated MAP_NOZERO). > A new field owner_uid is added the the mm_struct, and it is kept set to > the effective UID of the task that own the mm_struct. > A new field owner_uid is also added to the page struct. You will also need to take the task's SELinux security context into account. SUID programs should not be able to use this feature, either. > When pages exit (unmapped from) a vma, they are marked with the effective > UID of the mm_struct that owns it. > --- linux-2.6.mod.orig/include/linux/mm_types.h 2007-06-21 14:02:06.000000000 -0700 > +++ linux-2.6.mod/include/linux/mm_types.h 2007-06-25 19:11:22.000000000 -0700 > @@ -64,6 +64,7 @@ > struct list_head lru; /* Pageout list, eg. active_list > * protected by zone->lru_lock ! > */ > + int owner_uid; /* Last owner of the page */ > /* > * On machines where all RAM is mapped into kernel address space, > * we can simply calculate the virtual address. On machines with Since this is only set when the page is freed, could the owner_uid and security context be put inside a union with some fields that are not otherwise used for free pages? -- Politics is the struggle between those who want to make their country the best in the world, and those who believe it already is. Each group calls the other unpatriotic. - 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/