From owner-freebsd-current Tue Aug 25 11:09:54 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id LAA06511 for freebsd-current-outgoing; Tue, 25 Aug 1998 11:09:54 -0700 (PDT) (envelope-from owner-freebsd-current@FreeBSD.ORG) Received: from nlsystems.com (nlsys.demon.co.uk [158.152.125.33]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id LAA06505 for ; Tue, 25 Aug 1998 11:09:50 -0700 (PDT) (envelope-from dfr@nlsystems.com) Received: from herring.nlsystems.com (herring.nlsystems.com [10.0.0.2]) by nlsystems.com (8.9.1/8.8.5) with SMTP id TAA02256; Tue, 25 Aug 1998 19:08:18 +0100 (BST) Date: Tue, 25 Aug 1998 19:08:18 +0100 (BST) From: Doug Rabson To: Garrett Wollman cc: "John S. Dyson" , current@FreeBSD.ORG Subject: Re: Serious bug in vm_page.h in current In-Reply-To: <199808251441.KAA02038@khavrinen.lcs.mit.edu> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Tue, 25 Aug 1998, Garrett Wollman wrote: > < said: > > > On Tue, 25 Aug 1998, John S. Dyson wrote: > > >> PAGE_BWAKEUP would decr busy, and wakeup if PG_WANTED > >> and busy == 0. > >> > >> PAGE_WAKEUP would clear PG_BUSY, and wakeup if PG_WANTED. > >> > >> Each of the above would ignore the other condition. There will > >> be extra wakeups, but those won't significantly affect performance. > > > I don't understand this part of the code of the code very well. It > > doesn't seem to me that a few extra wakeups is a problem. Not waking up > > at all is a problem... > > This sounds very much like it could be related to the lockup Matt > Dillon and I have been seeing. I just rebooted newsswitch with this > change in it; I should know by the end of the day whether it had > any effect. I think that John's patch as posted will not work at all due to a misunderstanding. It will probably just cause hangs since vm_page::busy will be decremented but never incremented. -- Doug Rabson Mail: dfr@nlsystems.com Nonlinear Systems Ltd. Phone: +44 181 951 1891 Fax: +44 181 381 1039 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message