Re: [patch 10/15] Generic Mutex Subsystem, mutex-migration-helper-core.patch

Ingo Molnar
2005-12-20T04:49:07Z

* Christoph Hellwig <hch@infradead.org> wrote:

> On Mon, Dec 19, 2005 at 02:38:37AM +0100, Ingo Molnar wrote:
> >
> > introduce the mutex_debug type, and switch the semaphore APIs to it in a
> > type-sensitive way. Plain semaphores will still use the proper
> > arch-semaphore calls.
>
> I think we shouldn't introduce this one. It just encourages people to do
> really things.
^---("weird" ?)

ok. I can keep it a separate patch - it's needed for -rt, and it's also
a good debugging tool to test-drive the mutex implementation.

historically, i found 90% of the mutex.c bugs by stress-testing it from
userspace, but a crutial 10% did come from the DEBUG_MUTEX_FULL mode,
where almost all of the 7000+ semaphore users are switched over to
mutexes.

but in terms of keeping the upstream kernel code base clean, i agree
with a clean and separate set of mutex APIs that are introduced into
subsystems gradually.

> Everything else in the patchseries looks sensible to me.

great!

Ingo