Re: 2.4.19pre9aa1

[Andrea Arcangeli]

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
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