cvs commit: src/sys/kern kern_module.c
imp at bsdimp.com
Fri Jun 30 06:26:42 UTC 2006
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. Not
> > > all of the module event handlers are MP safe yet, so always acquire Giant
> > > for now when invoking module event handlers. Eventually we can add an
> > > MPSAFE flag or some such and add appropriate locking to all module event
> > > 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. With
> the mark as MPSAFE method (such as we've used for syscalls) we can mark things
> 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 I'm
> in the process of doing now with the syscall flag) all the while having a
> functioning system.
We have three cases right now:
(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.
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