From mboxrd@z Thu Jan 1 00:00:00 1970 Message-Id: In-Reply-To: <3AE1DCA8.A6EF6802@earthlink.net> References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Date: Sat, 21 Apr 2001 20:41:40 +0100 From: Jonathan Morton Subject: Re: suspend processes at load (was Re: a simple OOM ...) Sender: owner-linux-mm@kvack.org Return-Path: To: "Joseph A. Knapka" , "James A. Sutherland" Cc: linux-mm@kvack.org List-ID: >> Note that process suspension already happens, but with too fine a >> granularity (the scheduler) - that's what causes the problem. If one >> process were able to run uninterrupted for, say, a second, it would >> get useful work done, then you could switch to another. The current >> scheduling doesn't give enough time for that under thrashing >> conditions. > >This suggests that a very simple approach might be to just increase >the scheduling granularity as the machine begins to thrash. IOW, >use the existing scheduler as the "suspension scheduler". That might possibly work for some loads, mostly where there are some processes which are already swapped-in (and have sensible working sets) alongside the "thrashing" processes. That would at least give the well-behaved processes some chance to keep their "active" bits up to date. However, it doesn't help at all for the cases where some paging-in has to be done for a well-behaved but only-just-accessed process. Example of a critically important process under this category: LOGIN. :) IMHO, the only way to sensibly cater for this case (and a few others) is to update the page-replacement algorithm. -------------------------------------------------------------- from: Jonathan "Chromatix" Morton mail: chromi@cyberspace.org (not for attachments) big-mail: chromatix@penguinpowered.com uni-mail: j.d.morton@lancaster.ac.uk The key to knowledge is not to rely on people to teach you it. Get VNC Server for Macintosh from http://www.chromatix.uklinux.net/vnc/ -----BEGIN GEEK CODE BLOCK----- Version 3.12 GCS$/E/S dpu(!) s:- a20 C+++ UL++ P L+++ E W+ N- o? K? w--- O-- M++$ V? PS PE- Y+ PGP++ t- 5- X- R !tv b++ DI+++ D G e+ h+ r++ y+(*) -----END GEEK CODE BLOCK----- -- 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/