Re: [RFC 1/3] Framework for accurate node based statistics

From: Andi Kleen
Date: Tue Dec 06 2005 - 14:25:26 EST


On Tue, Dec 06, 2005 at 11:08:42AM -0800, Christoph Lameter wrote:
> On Tue, 6 Dec 2005, Andi Kleen wrote:
>
> > > +static inline void mod_node_page_state(int node, enum node_stat_item item, int delta)
> > > +{
> > > + vm_stat_diff[get_cpu()][node][item] += delta;
> > > + put_cpu();
> >
> > Instead of get/put_cpu I would use a local_t. This would give much better code
> > on i386/x86-64. I have some plans to port over all the MM statistics counters
> > over to local_t, still stuck, but for new code it should be definitely done.
>
> Yuck. That code uses atomic operations and is not aware of atomic64_t.

Hmm? What code are you looking at?

At least i386/x86-64/generic don't use any atomic operations, just
normal non atomic on bus but atomic for interrupts local rmw.

Do you actually need 64bit?

-Andi
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