Re: 2.4.19pre9aa1

[William Lee Irwin III <wli@holomorphy.com>]

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.

And thanks for looking into shm, I understand that area is a bit
painful to work around, but fixes are certainly needed there.


Cheers,
Bill