Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S268146AbUJOQYI (ORCPT ); Fri, 15 Oct 2004 12:24:08 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S268136AbUJOQVc (ORCPT ); Fri, 15 Oct 2004 12:21:32 -0400 Received: from mail-relay-4.tiscali.it ([213.205.33.44]:26243 "EHLO mail-relay-4.tiscali.it") by vger.kernel.org with ESMTP id S268134AbUJOQUM (ORCPT ); Fri, 15 Oct 2004 12:20:12 -0400 Date: Fri, 15 Oct 2004 18:20:00 +0200 From: Andrea Arcangeli To: Albert Cahalan Cc: Hugh Dickins , linux-kernel mailing list , Andrew Morton OSDL , William Lee Irwin III , Albert Cahalan Subject: Re: per-process shared information Message-ID: <20041015162000.GB17849@dualathlon.random> References: <1097846353.2674.13298.camel@cube> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1097846353.2674.13298.camel@cube> X-GPG-Key: 1024D/68B9CB43 13D9 8355 295F 4823 7C49 C012 DFA1 686E 68B9 CB43 X-PGP-Key: 1024R/CB4660B9 CC A0 71 81 F4 A0 63 AC C0 4B 81 1D 8C 15 C8 E5 User-Agent: Mutt/1.5.6i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1707 Lines: 32 On Fri, Oct 15, 2004 at 09:19:13AM -0400, Albert Cahalan wrote: > I don't see why it is such trouble to provide the old data. I agree with you w.r.t. binary compatibility, here it's even a "source compatibility" matter, a recompile wouldn't fix it. However I wasn't exactly advocating to keep it 100% backwards compatible in this case: somebody already broke it from 2.5.x to 2.6.9-rc, and since there was a very good reason for that, we should probably declare it broken. Here there has been a very strong technical reason to break statm, but they didn't break binary and source compatibility gratuitously like some solaris kernel developer seems to think in some blog. the problem is that when ps xav wants to know the RSS it reads statm, so we just cannot hurt ps xav to show the "old shared" information that would be extremely slow to collect. I was only not happy about dropping the old feature completely instead of providing it with a different new API. Now I think the solution Hugh just proposed with the anon_rss should mimic the old behaviour well enough and it's probably the right way to go, it's still not literally the same, but I doubt most people from userspace could notice the difference, and most important it provides useful information, which is the number of _physical_ pages mapped that aren't anonymous memory, this is very valuable info and it's basically the same info that people was getting from the old "shared". So I like it. - 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/