Messages in this thread | | | Date | Wed, 05 Jan 2011 19:35:19 +0200 | From | Avi Kivity <> | Subject | Re: [RFC -v3 PATCH 2/3] sched: add yield_to function |
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On 01/05/2011 07:28 PM, Peter Zijlstra wrote: > On Wed, 2011-01-05 at 19:19 +0200, Avi Kivity wrote: > > On 01/05/2011 07:15 PM, Peter Zijlstra wrote: > > > On Wed, 2011-01-05 at 19:10 +0200, Avi Kivity wrote: > > > > On 01/04/2011 08:04 PM, Peter Zijlstra wrote: > > > > > This definitely wants to be EXPORT_SYMBOL_GPL() and if it were possible > > > > > I'd make it so only kvm.o could use it. It really sucks that kvm is a > > > > > module. > > > > > > > > Why does it suck? I mean apart from the "virtualization is crap" song. > > > > > > Because it needs hooks all over the core kernel, like this yield_to() > > > stuff. Exporting this might lead to others wanting to use it too. > > > > Well, it's very convenient for development (modprobe vs. reboot). > > Get a machine that boots fast ;-), it might be because I've never worked > on anything modular, but typically stuff crashes when I got it wrong, in > which case you're forced to power-cycle anyway.
I often get by with just guest crashes. Or maybe it oopses, I look around, then reboot at my leisure.
> > What hooks do you object to? > > Don't really keep a list, but every now and again see something that > makes me think that ought not be exported. > > > mmu notifiers are useful for some drivers, sched > > notifiers are useful for cmwq and possibly perf? > > Both use explicit function calls because its easier to read the code and > faster.
I doubt it's measurable, especially for perf with the msr tweaking it does.
Tejun, why did you end up not using preempt_notifiers in cmwq?
-- error compiling committee.c: too many arguments to function
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