From owner-cvs-all Tue Apr 3 11:13:57 2001 Delivered-To: cvs-all@freebsd.org Received: from earth.backplane.com (earth-nat-cw.backplane.com [208.161.114.67]) by hub.freebsd.org (Postfix) with ESMTP id 3534237B719; Tue, 3 Apr 2001 11:13:51 -0700 (PDT) (envelope-from dillon@earth.backplane.com) Received: (from dillon@localhost) by earth.backplane.com (8.11.2/8.9.3) id f33ID4b58965; Tue, 3 Apr 2001 11:13:04 -0700 (PDT) (envelope-from dillon) Date: Tue, 3 Apr 2001 11:13:04 -0700 (PDT) From: Matt Dillon Message-Id: <200104031813.f33ID4b58965@earth.backplane.com> To: Garrett Rooney Cc: Alfred Perlstein , cvs-committers@FreeBSD.ORG, cvs-all@FreeBSD.ORG Subject: Re: cvs commit: src/sys/sys mbuf.h src/sys/kern uipc_mbuf.c References: <200104030315.f333FCX69312@freefall.freebsd.org> <20010403140457.B2952@electricjellyfish.net> Sender: owner-cvs-all@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG :On Mon, Apr 02, 2001 at 08:15:12PM -0700, Alfred Perlstein wrote: :> alfred 2001/04/02 20:15:12 PDT :> :> Modified files: :> sys/sys mbuf.h :> sys/kern uipc_mbuf.c :> Log: :> Use only one mutex for the entire mbuf subsystem. : :I can see how this makes some things cheaper by allowing you to only lock a :single mutex instead of several, but doesn't it also limit you to only a :single thread using the mbuf subsystem at a time? Since mbufs are used in a :fairly large number of places throught the system, wouldn't that be bad? : :I'm sure this has been thought through, I'm just trying to understand why this :will be better in the long run. Isn't the goal to have fine grained locking, :rather than single locks limiting access to subsystems? : :-- :garrett rooney Unix was not designed to stop you from What about using the BSDI hash-table-of-mutexes idea? Where mutex functionality is overloaded to some degree for any given subsystem. This gives us sufficient parallelism without polluting system structures with their own mutexes. -Matt To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message