From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from burns.conectiva (burns.conectiva [10.0.0.4]) by perninha.conectiva.com.br (Postfix) with SMTP id D6C8C16B1B for ; Wed, 18 Apr 2001 19:29:26 -0300 (EST) Date: Wed, 18 Apr 2001 19:29:26 -0300 (BRST) From: Rik van Riel Subject: Re: suspend processes at load (was Re: a simple OOM ...) In-Reply-To: Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Szabolcs Szakacsits Cc: "James A. Sutherland" , linux-mm@kvack.org List-ID: On Thu, 19 Apr 2001, Szabolcs Szakacsits wrote: > > They will get this feedback, and more effectively than they do now: > > right now, they are left with a dead box they have to reboot. With > > Not if they RTFM. Moreover thrashing != dead. > > > IF you overload the system to extremes, then your processes will stop > > running for brief periods. Right now, they ALL stop running > > indefinitely! > > This is not true. There *is* progress, it just can be painful slow. "Painfully slow" when you are thrashing == "root cannot login because his login times out every time he tries to login". THIS is why we need process suspension in the kernel. Also think about the problem a bit more. If the "painfully slow progress" is getting less work done than the amount of new work that's incoming (think of eg. a mailserver), then the system has NO WAY to ever recover ... at least, not without the system administrator walking by after the weekend. OTOH, when the kernel suspends SOME tasks, so the others can run at full speed (and then switches, etc..), then the system is able to run all tasks to completion and crawl out of the overload situation. This is nothing different from CPU scheduling, except that this happens on a larger timescale and is only done to rescue the system in an emergency. Or did you want to get rid of preemptive multitasking too ? regards, Rik -- Linux MM bugzilla: http://linux-mm.org/bugzilla.shtml Virtual memory is like a game you can't win; However, without VM there's truly nothing to lose... http://www.surriel.com/ http://www.conectiva.com/ http://distro.conectiva.com/ -- 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/