From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756916AbYGGSfl (ORCPT ); Mon, 7 Jul 2008 14:35:41 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754691AbYGGSfU (ORCPT ); Mon, 7 Jul 2008 14:35:20 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:49850 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754395AbYGGSfS (ORCPT ); Mon, 7 Jul 2008 14:35:18 -0400 Date: Mon, 7 Jul 2008 11:34:16 -0700 (PDT) From: Linus Torvalds To: Matt Mackall cc: Andrew Morton , Alexey Dobriyan , torvalds@linuxfoundation.org, akpm@linuxfoundation.org, linux-kernel@vger.kernel.org, Dave Hansen Subject: Re: *sigh* /proc/*/pagemap In-Reply-To: <1215454997.11311.165.camel@calx> Message-ID: References: <20080704185312.052e7145.akpm@linux-foundation.org> <1215454997.11311.165.camel@calx> User-Agent: Alpine 1.10 (LFD 962 2008-03-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 7 Jul 2008, Matt Mackall wrote: > > It exists to make the VM stop being a big black box. Before now the VM > exposed little beyond statistics, many of which are basically > meaningless (RSS?). With pagemap, you can actually see precisely where > things are getting allocated, how they're getting shared, etc. Think > NUMA, think cell phones. Umm. How about setting it under CONFIG_DEBUG_VM or something like that then? Right now it's not even _asked_ about, unless you're EMBEDDED, and defaults to 'y'. Which means that it has all the downsides, an none of the upsides, for 99.99% of all users. Linus