From owner-cvs-all Mon Dec 30 3:11:33 2002 Delivered-To: cvs-all@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 9177837B401; Mon, 30 Dec 2002 03:11:31 -0800 (PST) Received: from mailman.zeta.org.au (mailman.zeta.org.au [203.26.10.16]) by mx1.FreeBSD.org (Postfix) with ESMTP id 1E64D43ED1; Mon, 30 Dec 2002 03:11:30 -0800 (PST) (envelope-from bde@zeta.org.au) Received: from katana.zip.com.au (katana.zip.com.au [61.8.7.246]) by mailman.zeta.org.au (8.9.3/8.8.7) with ESMTP id WAA05756; Mon, 30 Dec 2002 22:11:17 +1100 Date: Mon, 30 Dec 2002 22:13:16 +1100 (EST) From: Bruce Evans X-X-Sender: bde@gamplex.bde.org To: phk@FreeBSD.org Cc: cvs-committers@FreeBSD.org, Subject: Re: cvs commit: src/sys/sys _mutex.h In-Reply-To: <3507.1041241745@critter.freebsd.dk> Message-ID: <20021230220721.Y46191-100000@gamplex.bde.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII 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 Mon, 30 Dec 2002 phk@FreeBSD.org wrote: > In message <20021230142740.R44529-100000@gamplex.bde.org>, Bruce Evans writes: > >On Sun, 29 Dec 2002, Poul-Henning Kamp wrote: > > > >> phk 2002/12/29 03:14:41 PST > >> > >> Modified files: > >> sys/sys _mutex.h > >> Log: > >> Save 16 bytes per mutex if MUTEX_PROFILING is not defined. > >> > >> MUTEX_PROFILING is in opt_global.h, so this does not introduce a risk of > >> variant structure sizes unless foreign kernel modules are used. > > > >Not so. This breaks all modules, not just foreign ones, since > >opt_global.h is not included in any module, and even if it were then > >its setting for some modules might differ from the setting in the > >kernel. > > Ok, we should make MUTEX_PROFILING an undocumented option then. No, we should put it back like it was or implement it in out-of-band storage. > A cost of 16 bytes per mutex is not warranted for a "only once in > a blue moon" option. This can be considered a feature. It inhibits use of thousands, if not hundreds of thousands of locks. Another hack would be to make it the default for modules like many other options. This could be considered a feature. It rewards use of modules with another pessimization. Bruce To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message