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: [EMAIL PROTECTED]
Nonlinear Systems Ltd. Phone: +44 20 8442 9037
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