Date: Tue, 25 Apr 2000 21:50:25 +0100 (BST) From: Doug Rabson <dfr@nlsystems.com> To: Jake Burkholder <jburkhol@home.com> Cc: Bruce Evans <bde@zeta.org.au>, Boris Popov <bp@butya.kz>, freebsd-current@freebsd.org Subject: Re: SMP changes and breaking kld object module compatibility Message-ID: <Pine.BSF.4.21.0004252146030.79607-100000@salmon.nlsystems.com> In-Reply-To: <20000425160340.AE322BCA7@io.yi.org>
next in thread | previous in thread | raw e-mail | index | archive | help
On Tue, 25 Apr 2000, Jake Burkholder wrote: > > On Tue, 25 Apr 2000, Boris Popov wrote: > > > > > simple_lock* functions has breakage too. They defined as macros > > > for non-SMP case and as functions for SMP. > > > > This currently apparently affects the following modules: > > > > ccd > > cd9660 > > msdosfs > > nfs > > ntfs > > nwfs > > vinum > > > > All of these functions reference simple_lock() if it is not defined away. > > > > Bruce > > Has anyone thought about using kobj(9) for this? > > For example, it should be possible to make simple_lock and lockmgr locks > safe for use from modules by introducing a lock_if.h, which has > abstract version of all the lock routines. A class would be compiled > with null implementations for UP, or the 'lock'ed implementations for SMP. > The old functions would call through an instance of that class, automagically > finding the right method. Eventually this could be a runtime abstraction, > with both up and smp classes compiled into the kernel, and objects initialized > with the right method table at boot time. > > I have diffs in the works if anyone is interested. Its nice to see someone actually using kobj so soon. There is a possible performance problem though - kobj method calls are roughly 20% slower than direct function calls. Having said that, this isn't that slow - I timed a method call to a two argument function at ~40ns on a 300MHz PII. I could improve this for some applications (including this one) by providing a mechanism for an application to cache the function pointer returned by the method lookup. -- Doug Rabson Mail: dfr@nlsystems.com Nonlinear Systems Ltd. Phone: +44 20 8442 9037 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?Pine.BSF.4.21.0004252146030.79607-100000>