Re: [rfc 19/45] cpu alloc: NFS statistics

[Trond Myklebust]

On Tue, 2007-11-20 at 12:49 -0800, Christoph Lameter wrote:
> On Tue, 20 Nov 2007, Mathieu Desnoyers wrote:
> 
> > > Index: linux-2.6/fs/nfs/iostat.h
> > > ===================================================================
> > > --- linux-2.6.orig/fs/nfs/iostat.h	2007-11-15 21:17:24.391404458 -0800
> > > +++ linux-2.6/fs/nfs/iostat.h	2007-11-15 21:25:33.167654066 -0800
> > > @@ -123,7 +123,7 @@ static inline void nfs_inc_server_stats(
> > >  	int cpu;
> > >  
> > >  	cpu = get_cpu();
> > > -	iostats = per_cpu_ptr(server->io_stats, cpu);
> > > +	iostats = CPU_PTR(server->io_stats, cpu);
> > >  	iostats->events[stat] ++;
> > 
> > Is there a way to change this into a CPU_ADD ?
> 
> Yes I must have missed that.
> 
> Could be
> 
> CPU_INC(server->io_stats->events[stat]);
> 
> > 
> > >  	put_cpu_no_resched();
> > 
> > Why put_cpu_no_resched here ?
> 
> We do not want to reschedule here? We may have already disabled interrupts 
> or some such thing.

Some of these statistics are updated from inside a spinlocked
environment, hence the put_no_resched().

Trond

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