From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Mon, 3 Jul 2000 12:06:36 +0100 From: "Stephen C. Tweedie" Subject: Re: a joint letter on low latency and Linux Message-ID: <20000703120636.B2931@redhat.com> References: <200006301310.JAA06222@tsx-prime.MIT.EDU> <200006301506.LAA12457@renoir.op.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200006301506.LAA12457@renoir.op.net>; from pbd@Op.Net on Fri, Jun 30, 2000 at 11:03:08AM -0400 Sender: owner-linux-mm@kvack.org Return-Path: To: Paul Barton-Davis Cc: "Theodore Y. Ts'o" , linux-kernel@vger.rutgers.edu, linux-mm@kvack.org List-ID: Hi, On Fri, Jun 30, 2000 at 11:03:08AM -0400, Paul Barton-Davis wrote: > Well, I'm sympathetic to this. But just yesterday, I saw Stephen > Tweedie saying that the VM system needed another fairly significant > redesign begore it could be considered ready for 2.4.0. It needs some really careful thinking, and a small (though still significant) amount of reworking of *highly* localised functions before 2.4. It also needs a complete overhaul, but that's a 2.5 issue. For 2.4 the objective has to be minimum necessary change. The trouble is that 2.4 VM performance has sufficiently bad worst case behaviour right now that some change is necessary --- the existing behaviour is a serious bug needing fixed. It is too late to change the VM mechanisms for 2.4, but the policy code still needs a good, hard think, since we currently perform much much worse than 2.2 at some jobs. It IS too late to add features over and above what we already have in the source tree. That's why we've got a substantial wish-list of experimental stuff to explore for the 2.5 VM in addition to the fixes needed for 2.4. --Stephen -- 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/