Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 12 Dec 2001 03:40:47 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 12 Dec 2001 03:40:37 -0500 Received: from vasquez.zip.com.au ([203.12.97.41]:24076 "EHLO vasquez.zip.com.au") by vger.kernel.org with ESMTP id ; Wed, 12 Dec 2001 03:40:20 -0500 Message-ID: <3C1717C3.82CC4A63@zip.com.au> Date: Wed, 12 Dec 2001 00:39:31 -0800 From: Andrew Morton X-Mailer: Mozilla 4.77 [en] (X11; U; Linux 2.4.17-pre8 i686) X-Accept-Language: en MIME-Version: 1.0 To: Andrea Arcangeli CC: Marcelo Tosatti , lkml Subject: Re: 2.4.16 & OOM killer screw up (fwd) In-Reply-To: <3C151F7B.44125B1@zip.com.au>, <3C151F7B.44125B1@zip.com.au>; <20011211011158.A4801@athlon.random> <3C15B0B3.1399043B@zip.com.au>, <3C15B0B3.1399043B@zip.com.au>; from akpm@zip.com.au on Mon, Dec 10, 2001 at 11:07:31PM -0800 <20011211144223.E4801@athlon.random> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Andrea Arcangeli wrote: > > > [ big snip. Addressed in other email ] > > it should be simple, mainline swapouts more, so it's less likely to > trash away some useful cache. > > just try -aa after a: > > echo 10 >/proc/sys/vm/vm_mapped_ratio > > it should swapout more and better preserve the cache. -aa swapout balancing seems very good indeed to me. > > > > In my swapless testing, I burnt HUGE amounts of CPU in flush_tlb_others(). > > > > So we're madly trying to swap pages out and finding that there's no swap > > > > space. I beleive that when we find there's no swap left we should move > > > > the page onto the active list so we don't keep rescanning it pointlessly. > > > > > > yes, however I think the swap-flood with no swap isn't a very > > > interesting case to optimize. > > > > Running swapless is a valid configuration, and the kernel is doing > > I'm not saying it's not valid or non interesting. > > It's the mix "I'm running out of memory and I'm swapless" that is the > case not interesting to optimize. > > If you're swapless it means you've enough memory and that you're not > running out of swap. Otherwise _you_ (not the kernel) are wrong not > having swap. um. Spose so. > ... > > > The VM code lacks comments, and nobody except yourself understands > > what it is supposed to be doing. That's a bug, don't you think? > > Lack of documentation is not a bug, period. Also it's not true that I'm > the only one who understands it. For istance Linus understand it > completly, I am 100% sure. > > Anyways I wrote a dozen of slides on the VM with some graph showing the > design of the VM if anybody can better learn from a slide than from the > code. That's good. Your elevator design slides were very helpful. However offline documentation tends to go stale. A nice big block comment maintained by a programmer who cares goes a loooog way. > I believe the slides are useful to understand the design, but if you > want to change one line of code slides or not you've to read the code. > Everybody is complaining about documentation. This is a red-herring. > There's no documentation that allows you to hack the previous VM code. > I'd ask how many of the people happy with the previous documentation > were effectively VM developers. Except for some possible misleading > comment in the current code that we may have not updated yet, I don't > think there's been a regression in documentation. > Sigh. Just because the current core kernel looks like it was scrawled in crayon by an infant doesn't mean that everyone has to eschew literate, mature, competent and maintainable programming practices. - - 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/