From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qg0-f52.google.com (mail-qg0-f52.google.com [209.85.192.52]) by kanga.kvack.org (Postfix) with ESMTP id 4A7F46B0036 for ; Wed, 28 May 2014 02:14:50 -0400 (EDT) Received: by mail-qg0-f52.google.com with SMTP id a108so16672221qge.11 for ; Tue, 27 May 2014 23:14:50 -0700 (PDT) Received: from bombadil.infradead.org (bombadil.infradead.org. [2001:1868:205::9]) by mx.google.com with ESMTPS id t6si20742561qag.120.2014.05.27.23.14.49 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 27 May 2014 23:14:49 -0700 (PDT) Date: Wed, 28 May 2014 08:14:39 +0200 From: Peter Zijlstra Subject: Re: [RFC][PATCH 0/5] VM_PINNED Message-ID: <20140528061439.GI11096@twins.programming.kicks-ass.net> References: <20140527102909.GO30445@twins.programming.kicks-ass.net> <20140527144655.GC19143@laptop.programming.kicks-ass.net> <20140527153143.GD19143@laptop.programming.kicks-ass.net> <20140527164341.GD11074@laptop.programming.kicks-ass.net> <20140527172930.GE11074@laptop.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="rwwPlZPbpBX9O0Yk" Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: Christoph Lameter Cc: Konstantin Khlebnikov , "linux-mm@kvack.org" , Linux Kernel Mailing List , Thomas Gleixner , Andrew Morton , Hugh Dickins , Mel Gorman , Roland Dreier , Sean Hefty , Hal Rosenstock , Mike Marciniszyn --rwwPlZPbpBX9O0Yk Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, May 27, 2014 at 03:00:15PM -0500, Christoph Lameter wrote: > On Tue, 27 May 2014, Peter Zijlstra wrote: >=20 > > > What do you mean by shared pages that are not shmem pages? AnonPages = that > > > are referenced from multiple processes? > > > > Regular files.. they get allocated through __page_cache_alloc(). AFAIK > > there is nothing stopping people from pinning file pages for RDMA or > > other purposes. Unusual maybe, but certainly not impossible, and > > therefore we must be able to handle it. >=20 > Typically structures for RDMA are allocated on the heap. Sure, typically. But that's not enough. > The main use case is pinnning the executable pages in the page cache? No.. although that's one of the things the -rt people are interested in. > > > Migration is expensive and the memory registration overhead already > > > causes lots of complaints. > > > > Sure, but first to the simple thing, then if its a problem do something > > else. >=20 > I thought the main issue here were the pinning of IB/RDMA buffers. It is,.. but you have to deal with the generic case before you go off doing specific things. You're approaching the problem from the wrong way; first make it such that everything works, only then, optimize some specific case, if and when it becomes important. Don't start by only looking at the one specific case you're interested in and forget about everything else. --rwwPlZPbpBX9O0Yk Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQIcBAEBAgAGBQJThX7JAAoJEHZH4aRLwOS6tRkQAINtgJGCOtIztBNH+RRHXwCG UZg0rfSYPK5QMpzJ31+Yemlgr1B2+VIu8tHNb5uM0u0qTinNuOdIYqygSoc7WbRl 7F3adXn96uWg75gsE7iZqMbXnKpiQdnFDnY5laPOpwsgyKLyhJqrDR3zDhnPLQYm gmSrLI1c+RK+2EvQDd0q5Zo8LsyJASIHwQD1zwtcZq3slcVVPw/ACHdik+6xf9b1 X6DRCIPO5HZALRQrkz0b1I1MBlxVR0uW7YC30UkEHuNecQNcRAhXDN3Q9b75cU87 zBKEx+et/EhKatiAOQ933qkfsXniYCErParBieUraRJ6+vAQ/oBbjXopkRWUW6ll gwLKTba4N+xIpb/y1zys09d2skNOoQIcZ5PIndRrm3m0qW4kPKuc32Lzkck5I44+ Lz9jCqQlPaFqAaL6+1+NxxYI+ENiE3QjjdUh4bkGpUzMaLjZUdOlc8DnYppz3FOW Aw6S5PUuYVPYrII0jKDT/q2h/N+vlkQOAYSdaScy1at4kUpMEQyyDlgrvmdN4X1s UsuFwrAVaToP1PqsQ6zE2RgDyFC4lqwwJagRoMzlCEhc0x/ZitfY5xbT9zjTKUW9 LPp4bGSoADpPp+kaohtgyQ/sJ+HDuWLMzBGKJX4UPMPfMECiFa7r8iTbWpA6FGuz Y2iEJ6RABKEh8fkjD3Xm =n8kK -----END PGP SIGNATURE----- --rwwPlZPbpBX9O0Yk-- -- 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