From owner-freebsd-current Fri Mar 8 15:49:43 2002 Delivered-To: freebsd-current@freebsd.org Received: from apollo.backplane.com (apollo.backplane.com [216.240.41.2]) by hub.freebsd.org (Postfix) with ESMTP id 17C6137B402; Fri, 8 Mar 2002 15:49:38 -0800 (PST) Received: (from dillon@localhost) by apollo.backplane.com (8.11.6/8.9.1) id g28Nnbi80049; Fri, 8 Mar 2002 15:49:37 -0800 (PST) (envelope-from dillon) Date: Fri, 8 Mar 2002 15:49:37 -0800 (PST) From: Matthew Dillon Message-Id: <200203082349.g28Nnbi80049@apollo.backplane.com> To: Jake Burkholder Cc: Robert Watson , FreeBSD current users Subject: Re: Patch for critical_enter()/critical_exit() & interrupt assem References: <200203072143.g27LhaL97112@harmony.village.org> <20020307205844.C12044@locore.ca> <200203080304.g2834n571759@apollo.backplane.com> <20020308024653.B14181@locore.ca> <200203080923.g289N1N74926@apollo.backplane.com> <20020308151743.B17591@locore.ca> Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG :The reason is that if they are in MI code they automatically apply to all :platforms and can't get out sync. When they are modified to handle preemption :the freebsd kernel will be fully preemptive. Not, it works on i386 and its :believed to work on alpha and powerpc is not preemptive at all and we don't If the routines were large this would be an issue, but we are talking between 1 and 5 lines of MI code verses potentially many more lines of MD code and I find it virtually impossible for such a small amount of code to 'get out of sync'. :even know about ia64 (not to dump on other platforms, this is just example of :how things go sometimes). I understand that this argument may be sentimental :and may not hold water in a technial discussion. As such I will not stop you :from making them MD if you disagree (not to imply that I have the power to do :so, I don't), I just think that keeping them MI is the right thing to do. : :I must admit that having them be MD will allow me to make optimizations for :sparc64 that I have wanted to. However, I do not think that this is better :for freebsd as a whole. : :> :> :... :... :The point is not wether its easy or not, the point is that this is an :important feature that may have been forgotten about. I use this on :a daily basis in sparc64 development and I would be upset if it was :broken there for any amount of time, not that this patch will affect it. :I am confident that you will fix any problems that arise, but I would :rather the next person that tries to do some debugging not be confused :by something being different, or by it not working and having to wait for :a fix, even if that amount of time is insignificant. If you do not feel :that this needs to be looked at before you commit then that is fine, again :I cannot stop you. I know many other committers who would not feel that :way about a patch of their own and I think that standard is worth adhereing :to. I apologize if this sounds like a lecture or if this offends you, it :is just how I feel. : :Jake I'm not sure what you are refering to here. The fast interrupt deferral stuff only applies to I386. In anycase, I certainly haven't forgotten about debugger support for I386, but I didn't go to great lengths to test whether the DDB backtrace operates as expected for the fast-interrupt-restart case either. -Matt Matthew Dillon To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message