Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752598Ab0DMSDQ (ORCPT ); Tue, 13 Apr 2010 14:03:16 -0400 Received: from bombadil.infradead.org ([18.85.46.34]:51058 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750776Ab0DMSDO convert rfc822-to-8bit (ORCPT ); Tue, 13 Apr 2010 14:03:14 -0400 Subject: Re: [PATCH] ummunotify: Userspace support for MMU notifications From: Peter Zijlstra To: Roland Dreier Cc: =?ISO-8859-1?Q?H=E5kon?= Bugge , Jason Gunthorpe , Andrew Morton , Eric B Munson , linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org, rolandd@cisco.com, pavel@ucw.cz, mingo@elte.hu, jsquyres@cisco.com In-Reply-To: References: <1271053337-7121-1-git-send-email-ebmunson@us.ibm.com> <20100412160359.1d9074dc.akpm@linux-foundation.org> <20100412235937.GF15629@obsidianresearch.com> <3251DDDA-D705-4B1E-9595-9C24709EF146@Sun.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT Date: Tue, 13 Apr 2010 20:02:54 +0200 Message-ID: <1271181774.4807.1868.camel@twins> Mime-Version: 1.0 X-Mailer: Evolution 2.28.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1003 Lines: 19 On Tue, 2010-04-13 at 10:57 -0700, Roland Dreier wrote: > Are those system calls the only possible way that virtual to physical > mappings can change? Can't page migration or something like that > potentially affect things? And even if you did have hooks into every > system call that mattered (keep in mind that relying on glibc is not > enough, since an MPI application may not use glibc) would decoding them > and figuring out what happened really be preferable to a single event > type that tells you exactly what address range was affected? Yeah, virtual<->physical maps can change through swapping, page migration, memory compaction, huge-page aggregation (the latter two not yet being upstream). Even mlock() doesn't pin virtual<->physical maps. -- 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/