From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Fri, 18 May 2001 23:12:32 -0300 (BRST) From: Rik van Riel Subject: Re: Linux 2.4.4-ac10 In-Reply-To: <20010518235852.R8080@redhat.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: "Stephen C. Tweedie" Cc: Mike Galbraith , Ingo Oeser , linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: On Fri, 18 May 2001, Stephen C. Tweedie wrote: > On Fri, May 18, 2001 at 07:44:39PM -0300, Rik van Riel wrote: > > > This is the core of why we cannot (IMHO) have a discussion > > of whether a patch introducing new VM tunables can go in: > > there is no clear overview of exactly what would need to be > > tunable and how it would help. > > It's worse than that. The workload on most typical systems is not > static. The VM *must* be able to cope with dynamic workloads. You > might twiddle all the knobs on your system to make your database run > faster, but end up in such a situation that the next time a mail flood > arrives for sendmail, the whole box locks up because the VM can no > longer adapt. That's another problem, indeed ;) Ingo, Mike, please keep this in mind when designing tunables or deciding which test you want to run today in order to look how the VM is performing. Basic rule for VM: once you start swapping, you cannot win; All you can do is make sure no situation loses really badly and most situations perform reasonably. Rik -- Virtual memory is like a game you can't win; However, without VM there's truly nothing to lose... http://www.surriel.com/ http://distro.conectiva.com/ Send all your spam to aardvark@nl.linux.org (spam digging piggy) -- 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.eu.org/Linux-MM/