Messages in this thread |  | | Subject | Re: Linux Preemptive patch success 2.4.10-pre4 + lots of other patches | From | Robert Love <> | Date | 07 Sep 2001 01:20:40 -0400 |
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On Fri, 2001-09-07 at 01:19, Daniel Phillips wrote: > On September 7, 2001 06:45 am, Robert Love wrote: > > On Fri, 2001-09-07 at 00:36, Christoph Lameter wrote: > > > Given the minimal nature of the patch I would suggest that it become part > > > of 2.4.10 or 11 > > > > Are you kidding? We will be lucky to see this in during 2.5. > > Its a pretty big change. It makes the Linux kernel preemptible. > > CONFIG_PREEMPT
and... ?
> > This is a fairly big move, one I don't think any of the major Unices have > > done. > > The other Unices are at least evenly split, or mostly preemptible. > Typically, a more complex strategy is used where spinlocks can sleep > after a few spins. This patch is very conservative in that regard, > it basically just uses the structure we already have, SMP spinlocks.
I did not know other Unices were (in general) preemptible. Solaris is? The only one I thought was preemptible was Irix.
Anyhow, you are right about the simplistic approach we take. There are a few alternatives: mixing mutexes and shorter locks, priority-bearing semaphores, changing the way the preemption count works, etc.
> > The only reason the patch is not _huge_ is because the Linux > > kernel is already setup for concurrency of this nature -- it does SMP. > > > > I suggest you read > > http://www.linuxdevices.com/articles/AT4185744181.html > > http://www.linuxdevices.com/articles/AT5152980814.html > > http://kpreempt.sourceforge.net > > > > and my previous threads on this issue, for more informaiton. > > Hmm, how did you read those and come to such a different conclusion?
What different conclusion? What are you even arguing with me about?
Do you think I am against a preemptible kernel? I _posted_ the damn patch, of course I am not.
I probably agree with whatever you are thinking.
-- Robert M. Love rml at ufl.edu rml at tech9.net
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