On Thu, 1 Nov 2012, Jesse Gross wrote: > On Thu, Nov 1, 2012 at 7:33 AM, Christoph Lameter <c...@linux.com> wrote: > > On Thu, 1 Nov 2012, Shan Wei wrote: > > > >> But for different field in same per-cpu variable, how to guarantee n_missed > >> and n_hit are from same cpu? > >> this_cpu_read(dp->stats_percpu->n_missed); > >> [processor changed] > >> this_cpu_read(dp->stats_percpu->n_hit); > > > > What does current guarantee that? If it is guaranteed then you can use the > > __this_cpu_xxx ops. > > Preemption is disabled in all of the places where writes are done and > all of the reads are from foreign CPUs.
Since preemption is disabled no processor change can occur. So its safe to use __this_cpu ops throughout and they will operate on the current per cpu area. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
