Re: 2.4.19pre9aa1

[Andrea Arcangeli]

On Thu, May 30, 2002 at 03:40:09AM +0200, Andrea Arcangeli wrote:
> On Wed, May 29, 2002 at 06:32:00PM -0700, William Lee Irwin III wrote:
> > On Thu, May 30, 2002 at 03:01:25AM +0200, Andrea Arcangeli wrote:
> > > NOTE: this release is highly experimental, while it worked solid so far
> > > it's not well tested yet, so please don't use in production
> > > environments! (yet :)
> > > The o1 scheduler integration will take a few weeks to settle and to
> > > compile on all archs. I would suggest the big-iron folks to give this
> > > kernel a spin, in particular for o1, shm-rmid fix, p4/pmd fix,
> > > inode-leak fix. The only rejected feature is been the node-affine
> > > allocations of per-cpu data structures in the numa-sched (matters only
> > > for numa, but o1 is more sensible optimization for numa anyways).
> > > Currently only x86 and alpha compiles and runs as expected. x86-64,
> > > ia64, ppc, s390*, sparc64 doesn't compile yet. uml worst of all compiles
> > > but it doesn't run correctly :), however it runs pretty well too, simply
> > > it hangs sometime and you've to press a key in the terminal and then it
> > > resumes as if nothing has happened.
> > 
> > I noticed what looked like missed wakeups in tty code in early 2.4.x
> > ports of the O(1) scheduler, though I saw a somewhat different failure
> > mode, that is, the terminal echo would remain one character behind
> > forever (and if it happened again, more than one). I never got a real
> > answer to this, unfortunately, as it appeared to go away after a certain
> > revision of the scheduler. The failure mode you describe is slightly
> > different, but perhaps related.
> 
> interesting, a tty problem could explain it probably, but being it

JFYI: the uml-hang gone away with 2.4.19pre9aa2, not sure why. I start to
wonder that it happened because I didn't run a full 'make distclean'
while I was updating it, maybe it was miscompiled.

> reproducible only with uml it should be still some uml internal that
> broke, not a generic bug, there are no changes to the tty code and it's
> unlikely that only the tty code broke due a generic o1 bug and that
> additionally it is reproducible only in uml.
> 
> > 
> > And thanks for looking into shm, I understand that area is a bit
> > painful to work around, but fixes are certainly needed there.
> 
> you're very welcome.
> 
> Andrea

Andrea