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    SubjectRe: [rfc 19/45] cpu alloc: NFS statistics
    * Trond Myklebust (trond.myklebust@fys.uio.no) wrote:
    >
    > 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().
    >

    The we could use __get_cpu_var instead ? (since we know preemption is
    _always_ disabled when we are called) ?

    > Trond
    >

    --
    Mathieu Desnoyers
    Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal
    OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
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