From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: [PATCH/RFC] Shared page tables From: Arjan van de Ven In-Reply-To: <200601240210.04337.ak@suse.de> References: <200601240139.46751.ak@suse.de> <200601231853.54948.raybry@mpdtxmail.amd.com> <200601240210.04337.ak@suse.de> Content-Type: text/plain Date: Tue, 24 Jan 2006 08:06:37 +0100 Message-Id: <1138086398.2977.19.camel@laptopd505.fenrus.org> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Andi Kleen Cc: Ray Bryant , Dave McCracken , Robin Holt , Hugh Dickins , Linux Kernel , Linux Memory Management List-ID: > The randomization is not for cache coloring, but for security purposes > (except for the old very small stack randomization that was used > to avoid conflicts on HyperThreaded CPUs). I would be surprised if the > mmap made much difference because it's page aligned and at least > on x86 the L2 and larger caches are usually PI. randomization to a large degree is more important between machines than within the same machine (except for setuid stuff but lets call that a special category for now). Imo prelink is one of the better bets to get "all code for a binary/lib on the same 2 mb page", all distros ship prelink nowadays anyway (it's too much of a win that nobody can afford to not ship it ;) and within prelink the balance between randomization for security and 2Mb sharing can be struck best. In fact it needs know about the 2Mb thing anyway to place it there properly and for all binaries... the kernel just can't do that. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org