cvs commit: src/sys/kern kern_module.c
jhb at freebsd.org
Fri Jun 30 19:14:44 UTC 2006
On Friday 30 June 2006 01:58, Warner Losh wrote:
> From: John Baldwin <jhb at freebsd.org>
> Subject: Re: cvs commit: src/sys/kern kern_module.c
> Date: Tue, 27 Jun 2006 08:48:28 -0400
> > On Monday 26 June 2006 19:41, Sam Leffler wrote:
> > > John Baldwin wrote:
> > > > jhb 2006-06-26 18:34:45 UTC
> > > >
> > > > FreeBSD src repository
> > > >
> > > > Modified files:
> > > > sys/kern kern_module.c
> > > > Log:
> > > > Address a problem I missed in removing Giant from the kernel linker.
> > > > all of the module event handlers are MP safe yet, so always acquire
> > > > for now when invoking module event handlers. Eventually we can add
> > > > MPSAFE flag or some such and add appropriate locking to all module
> > > > handlers.
> > >
> > > I suggest we should be marking things !MPSAFE rather than MPSAFE.
> > >
> > > Sam
> > I would prefer that as well but that would require an exhaustive search of
> > all existing module event handlers to determine MPSAFE-ness up front.
> > the mark as MPSAFE method (such as we've used for syscalls) we can mark
> > MPSAFE (and/or add locking to make them MPSAFE) while doing the exhaustive
> > search and eventually when all are MPSAFE we can remove the flag (which
> > in the process of doing now with the syscall flag) all the while having a
> > functioning system.
> We have three cases right now:
> (1) Unknown
> (2) MPSAFE
> (3) NEEDS GIANT
> All the unknown ones need giant right now, or at least that's a
> reasonable guess. Certainly all the device driver ones do since you
> need giant to do certain device tree activities.
> Short of introducing a new API, I'm unsure how we'd be able to
> effectively and safely do NEEDS_GIANT marking in the interrum.
DECLARE_MODULE_MPSAFE() or some such is how one would do it, but for
now they are all in the (1) category.
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