Messages in this thread | | | Date | Tue, 15 Jun 2004 20:09:04 -0700 (PDT) | From | Linus Torvalds <> | Subject | Re: [PATCH] Performance regression in 2.6.7-rc3 |
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On Wed, 16 Jun 2004, Herbert Xu wrote: > > Martin J. Bligh <mbligh@aracnet.com> wrote: > > > > How the hell can that have any effect on non-threaded workloads? Perhaps > > some part of kernel compile *is* multi-threaded. It does seem to get > > make(1) with vfork(2) perhaps?
Very likely. And in the vfork() case it is definitely WRONG to try to reschedule (either threads _or_ processes), since the parent is going to go to sleep real soon now.
I think this code:
if (clone_flags & CLONE_VM) wake_up_forked_thread(p); else wake_up_forked_process(p);
is just wrong, and it should be replaced with
wake_up_new_process(p, clone_flags);
and then "wake_up_new_process()" can do the right thing, which is basically:
if (clone_flags & CLONE_VFORK) synchronous wakeup, same as pipe-will-block case else if (clone_flags & CLONE_VM) thread-wakeup-case else process-wakeup-case
No?
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