From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752872AbbAMDdz (ORCPT ); Mon, 12 Jan 2015 22:33:55 -0500 Received: from mx1.redhat.com ([209.132.183.28]:32851 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750783AbbAMDdy (ORCPT ); Mon, 12 Jan 2015 22:33:54 -0500 Message-ID: <54B491F8.1070909@redhat.com> Date: Mon, 12 Jan 2015 22:33:12 -0500 From: Rik van Riel User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.3.0 MIME-Version: 1.0 To: David Lang , Linus Torvalds CC: "Kirill A. Shutemov" , Catalin Marinas , Mark Langsdorf , Linux Kernel Mailing List , "linux-arm-kernel@lists.infradead.org" Subject: Re: Linux 3.19-rc3 References: <54AE7D53.2020305@redhat.com> <20150108134520.GC14200@e104818-lin.cambridge.arm.com> <54AEBE84.6090307@redhat.com> <20150108173408.GF17290@e104818-lin.cambridge.arm.com> <54AED10C.7090305@redhat.com> <20150109232707.GA6325@e104818-lin.cambridge.arm.com> <20150110003540.GA32037@node.dhcp.inet.fi> In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 01/09/2015 09:51 PM, David Lang wrote: > On Fri, 9 Jan 2015, Linus Torvalds wrote: > >> Big pages are a bad bad bad idea. They work fine for databases, >> and that's pretty much just about it. I'm sure there are some >> other loads, but they are few and far between. > > what about a dedicated virtualization host (where your workload is > a handful of virtual machines), would the file cache issue still > be overwelming, even though it's the virtual machines accessing > things? You would still have page cache inside the guest. Using large pages in the host, and small pages in the guest would not give you the TLB benefits, and that is assuming that different page sizes in host and guest even work... Using large pages in the guests gets you back to the wasted memory, except you are now wasting memory in a situation where you have less memory available in each guest. Density is a real consideration for virtualization. - -- All rights reversed -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQEcBAEBAgAGBQJUtJH4AAoJEM553pKExN6Dd3QH/ivcIo2n06Czg14/gL61MSHM uZPOuMGQt51DYtF3s3mtDHqWyZq9hafz+2hoSJDwGIvVE6hJKVJ5rvb/OcN7AEKe PWfru+bOvID0d4YOy38ax2tZwdItlL/sj1AbTbPXjnkLWm0yP3dYVM40dj47JvPy +aE3iHB+wPZ+xxUmQ5KIlpRydUS1fl+tdmsiyi41fSFu8X19YDtDSrPylLk3to/w 6RGbHWLxJQZXJk+pkVWuSELmzWRrCaNaE7XBlvP9VS4U8bRg8WYJJXax1FBKLGBO ygVt2OmqLi9dneN8ePNRUW8x2Y6OqjobDgCkOzTxJB8NrtRDJpSqWCI4W5xReBM= =WhPN -----END PGP SIGNATURE-----