From owner-freebsd-hackers@FreeBSD.ORG Fri Jan 13 09:46:06 2006 Return-Path: X-Original-To: freebsd-hackers@freebsd.org Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 9CAF116A41F for ; Fri, 13 Jan 2006 09:46:06 +0000 (GMT) (envelope-from kamalpr@gmail.com) Received: from wproxy.gmail.com (wproxy.gmail.com [64.233.184.194]) by mx1.FreeBSD.org (Postfix) with ESMTP id 1435743D45 for ; Fri, 13 Jan 2006 09:46:05 +0000 (GMT) (envelope-from kamalpr@gmail.com) Received: by wproxy.gmail.com with SMTP id i20so560742wra for ; Fri, 13 Jan 2006 01:46:05 -0800 (PST) DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:sender:to:subject:cc:in-reply-to:mime-version:content-type:references; b=RYmFXzuZf/KoFtRTM7nFjfxH5yWTMVsbEwiob6OdvyMh5OQ+QT9FRPblhHSoqbuXJC/K+SqVCxmhvW9L9gPCYjQq2MI8XGQxb55ktL4GsFhWKqzcFdw85BxQxkQy7GgWKLRzR/ptMW/T/0Y50q81Kj4NEr7DvnuBp3SlW/rPKG4= Received: by 10.65.15.15 with SMTP id s15mr1717444qbi; Fri, 13 Jan 2006 01:46:05 -0800 (PST) Received: by 10.65.43.10 with HTTP; Fri, 13 Jan 2006 01:46:05 -0800 (PST) Message-ID: Date: Fri, 13 Jan 2006 15:16:05 +0530 From: "Kamal R. Prasad" Sender: kamalpr@gmail.com To: prime In-Reply-To: <1fa17f810601122232l25551bc5n4e4a01ff6b7921e@mail.gmail.com> MIME-Version: 1.0 References: <1fa17f810601122232l25551bc5n4e4a01ff6b7921e@mail.gmail.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Cc: freebsd-hackers@freebsd.org Subject: Re: How priority propagation works on read/write lock? X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 13 Jan 2006 09:46:06 -0000 Priority need not be propagated to readers as they will not block other readers. Most likely, you only need to propagate to the writer to avoid priority inversron. regards -kamal On 1/13/06, prime wrote: > > Hi hackers, > I have a question about how priority propagation works on > read/write lock.On locks that have only one owner at a determinate > moment,we can simply propagate the priority to the owner of lock,but > read/write lock may have many owners at some time,so how can we know > who are the owners? > I browse the OpenSolaris' read/write lock implementation,and find > that, it simply treats the owner of the lock as NULL when readers own > the read/write lock.In this way,we can not propagate our priority to > all threads that block us. > > Thanks very much. > -- > Three passions, simple but overwhelmingly strong, have governed my life: > the longing for love, the search for knowledge, and unbearable pity for > the suffering of mankind. > ---------Bertrand Russell > _______________________________________________ > freebsd-hackers@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-hackers > To unsubscribe, send any mail to "freebsd-hackers-unsubscribe@freebsd.org= " >