From owner-cvs-all Mon Mar 18 10:24:40 2002 Delivered-To: cvs-all@freebsd.org Received: from mail12.speakeasy.net (mail12.speakeasy.net [216.254.0.212]) by hub.freebsd.org (Postfix) with ESMTP id 95F4C37B41B for ; Mon, 18 Mar 2002 10:24:16 -0800 (PST) Received: (qmail 21580 invoked from network); 18 Mar 2002 18:24:16 -0000 Received: from unknown (HELO server.baldwin.cx) ([216.27.160.63]) (envelope-sender ) by mail12.speakeasy.net (qmail-ldap-1.03) with DES-CBC3-SHA encrypted SMTP for ; 18 Mar 2002 18:24:16 -0000 Received: from laptop.baldwin.cx (gw1.twc.weather.com [216.133.140.1]) by server.baldwin.cx (8.11.6/8.11.6) with ESMTP id g2IIOiv53753; Mon, 18 Mar 2002 13:24:44 -0500 (EST) (envelope-from jhb@FreeBSD.org) Message-ID: X-Mailer: XFMail 1.5.2 on FreeBSD X-Priority: 3 (Normal) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8bit MIME-Version: 1.0 In-Reply-To: <200203181508.g2IF8Am41245@freefall.freebsd.org> Date: Mon, 18 Mar 2002 13:24:18 -0500 (EST) From: John Baldwin To: Brian Feldman Subject: RE: cvs commit: src/sys/vm vm_fault.c vm_glue.c vm_map.c vm_map. Cc: cvs-all@FreeBSD.org, cvs-committers@FreeBSD.org Sender: owner-cvs-all@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG On 18-Mar-2002 Brian Feldman wrote: > green 2002/03/18 07:08:10 PST > > Modified files: > sys/vm vm_fault.c vm_glue.c vm_map.c vm_map.h > vm_pageout.c vm_zone.c > Log: > Back out the modification of vm_map locks from lockmgr to sx locks. The > best path forward now is likely to change the lockmgr locks to simple > sleep mutexes, then see if any extra contention it generates is greater > than removed overhead of managing local locking state information, > cost of extra calls into lockmgr, etc. You can't sleep while holding a mutex. The problem here is that sx locks and lockmgr locks intentionally do not have identical semantics. I would follow Matt's suggested plan of "dumbing down" the lockmgr locks to a common base with sx locks, then change to sx locks, then do the optimizations for upgrades using the upgrade/downgrade mechanism sx locks provide (which will require a slightly different algorithm). -- 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 cvs-all" in the body of the message