Re: [RFC][PATCH 4/9] create aggregate kvm_total_used_mmu_pages value

[Avi Kivity]

On 06/16/2010 06:06 PM, Dave Hansen wrote:
> > > +static inline void kvm_mod_used_mmu_pages(struct kvm *kvm, int nr)
> > > +{
> > > +	kvm->arch.n_used_mmu_pages += nr;
> > > +	kvm_total_used_mmu_pages += nr;
> > >
> > >        
> > Needs an atomic operation, since there's no global lock here.  To avoid
> > bouncing this cacheline around, make the variable percpu and make
> > readers take a sum across all cpus.  Side benefit is that you no longer
> > need an atomic but a local_t, which is considerably cheaper.
> >      
> That's a good point.  All of the modifications are done under locks, but
> the fast path isn't any more.  I'll fix it up.
>
>    

Note, even before you moved the shrinker out of the lock, this was a 
problem.  kvm_mod_used_mmu_pages() is called not just from the shrinker 
code, we zap pages for other reasons as well.

--
error compiling committee.c: too many arguments to function

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/