Re: floating stacks?

[GOTO Masanori <gotom@debian.or.jp>]

At Mon, 17 Feb 2003 11:09:10 -0500,
Daniel Jacobowitz wrote:
> On Mon, Feb 17, 2003 at 10:25:07PM +0900, GOTO Masanori wrote:
> > At 17 Feb 2003 12:08:33 +0100,
> > Johannes Berg wrote:
> > > On Mon, 2003-02-17 at 12:07, GOTO Masanori wrote:
> > > > Is your architecure i386?  AFAIK, on i386 FLOATING_STACKS is defined.
> > > > We don't change such part of upstream glibc.  Or do I misunderstand
> > > > something?
> > > 
> > > Yes, it is, sorry for not noting that before-hand.
> > > 
> > > >From what I read on the newsgroup/mailing list archives, it is not
> > > enabled by default, because the implementation conflicts with something
> > > in 486 or so. 
> > > I'm not sure though, but I guess then it would boil down to the fact
> > > that debian has no i686 architecture.
> > >
> > > See here for more info:
> > > http://groups.google.com/groups?selm=aljnu3%24bpu%241%40rznews2.rrze.uni-erlangen.de
> > 
> > Yes, we are currently dropping i686 support.  This issue is i686 -opt
> > package benefit.
> > 
> > We're concentrating to fix and stabilize the various problem with
> > glibc 2.3.1.  We plan to provide i686 opt package, or new libc6
> > package which owns i686 optimized libraries.
> 
> This is not an answer to Johannes' question.  FLOATING_STACKS is only
> enabled on i386 if you specify an --enable-kernel of at least 2.3.99;
> that loses kernel 2.2 compatibility.  Debian can't do that.

Ah, that's right - we can't do so with the default glibc.

> Red Hat has a local patch to glibc which allows the dynamic loader to
> select a different copy of glibc based on the running kernel version, I
> think.  They use it to select between glibc and NPTL.  We could do the
> same thing for floating stacks, or we could wait and do it between the
> old LinuxThreads and NPTL.  Or even all three.

Thanks. it's interesting.

I guess sarge still uses kernel 2.2 or 2.4, so NPTL is still
unavailable on debian in default state (NPTL requires >= 2.5 kernel,
as you know).  To fulfill Johannes' request, we need such hacks for
ld.so and LinuxThreads as you said, with i686 -opt...

Regards,
-- gotom