From owner-freebsd-hackers Wed Jul 14 21:54:59 1999 Delivered-To: freebsd-hackers@freebsd.org Received: from peach.ocn.ne.jp (peach.ocn.ne.jp [210.145.254.87]) by hub.freebsd.org (Postfix) with ESMTP id 6020715516 for ; Wed, 14 Jul 1999 21:54:37 -0700 (PDT) (envelope-from dcs@newsguy.com) Received: from newsguy.com by peach.ocn.ne.jp (8.9.1a/OCN) id NAA29125; Thu, 15 Jul 1999 13:54:31 +0900 (JST) Message-ID: <378D6828.FCC3C120@newsguy.com> Date: Thu, 15 Jul 1999 13:48:40 +0900 From: "Daniel C. Sobral" X-Mailer: Mozilla 4.6 [en] (Win98; I) X-Accept-Language: pt-BR,ja MIME-Version: 1.0 To: Jason Thorpe Cc: tech-userlevel@netbsd.org, freebsd-hackers@FreeBSD.ORG Subject: Re: Swap overcommit (was Re: Replacement for grep(1) (part 2)) References: <199907142127.OAA01681@lestat.nas.nasa.gov> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Transfer-Encoding: 7bit Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG Jason Thorpe wrote: > > If you have a lot of users, all of which have buggy programs which eat > a lot of memory, per-user swap quotas don't necessarily save your butt. The chance of these buggy programs running at the same time is not exactly high... > And maybe the individual programs didn't encounter their resource limits. > > ...but the sheer number of these runaway things caused the overcommit to > be a problem. If malloc() or whatever had actually returned NULL at the > right time (i.e. as backing store was about to become overcommitted), then > these runaway processes would have stopped running away (they would have > gotten a SIGSEGV and died). > > Anyhow, my "lame undergrads" example comes from a time when PCs weren't > really powerful enough for the job (or something; anyhow, we didn't have > any in the department :-). My example is from a Sequent Balance (16 > ns32032 processors, 64M RAM [I think; been a while], 4.2BSD variant). So, tell me... when NetBSD gets it's non-overcommit switch, would you use it in the environment you describe? -- Daniel C. Sobral (8-DCS) dcs@newsguy.com dcs@freebsd.org "Would you like to go out with me?" "I'd love to." "Oh, well, n... err... would you?... ahh... huh... what do I do next?" To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message