From owner-freebsd-arch Sat Nov 17 8:40: 9 2001 Delivered-To: freebsd-arch@freebsd.org Received: from mail6.speakeasy.net (mail6.speakeasy.net [216.254.0.206]) by hub.freebsd.org (Postfix) with ESMTP id 4FD4537B416 for ; Sat, 17 Nov 2001 08:40:07 -0800 (PST) Received: (qmail 26684 invoked from network); 17 Nov 2001 16:39:40 -0000 Received: from unknown (HELO laptop.baldwin.cx) ([64.81.54.73]) (envelope-sender ) by mail6.speakeasy.net (qmail-ldap-1.03) with SMTP for ; 17 Nov 2001 16:39:40 -0000 Message-ID: X-Mailer: XFMail 1.4.0 on FreeBSD X-Priority: 3 (Normal) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8bit MIME-Version: 1.0 In-Reply-To: <3BF6652F.FC50C99A@mindspring.com> Date: Sat, 17 Nov 2001 08:40:06 -0800 (PST) From: John Baldwin To: Terry Lambert Subject: Re: Need review - patch for socket locking and ref counting Cc: freebsd-arch@FreeBSD.ORG, Peter Wemm , Matthew Dillon Sender: owner-freebsd-arch@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG On 17-Nov-01 Terry Lambert wrote: > Matthew Dillon wrote: >> >> I've thought about it a bit and I've come to the conclusion that >> we should *not* have multiple mutex pools. > > It's pretty obvious even under casual thought that the deadlock > avoidance can't work correctly in theis scenario, so you MUST > limit yourself to last acquisition. Err, witness doesn't do deadlock avoidance, and it just checks lock orders. However, the problem is that the order of a larger lock (reader writer lock) is being compared with those of its components. Obviously one is going to acquire the lock used to implement a reader/writer lock both while holding and not holding the reader/writer lock. Witness cannot efficiently handle this, so instead we disable witness checks on the component locks. > By the same token, it does not make sense to permit recursion on > such mutexes. Err, we don't on most mutexes. -- John Baldwin <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve!" - http://www.FreeBSD.org/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message