Messages in this thread Patch in this message | | | Date | Tue, 14 Nov 2017 14:08:55 -0800 | From | "Paul E. McKenney" <> | Subject | Re: [PATCH] perf mmap: Convert ACCESS_ONCE() to READ_ONCE() |
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On Tue, Nov 14, 2017 at 10:31:38AM +0000, Mark Rutland wrote: > Recently there was a treewide conversion of ACCESS_ONCE() to > {READ,WRITE}_ONCE(), but a new use was introduced concurrently by > commit: > > 1695849735752d2a ("perf mmap: Move perf_mmap and methods to separate mmap.[ch] files") > > Let's convert this over to READ_ONCE() so that we can remove the > ACCESS_ONCE() definitions in subsequent patches. > > Signed-off-by: Mark Rutland <mark.rutland@arm.com> > Cc: Arnaldo Carvalho de Melo <acme@redhat.com> > Cc: Ingo Molnar <mingo@redhat.com> > Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> > Cc: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Woo-hoo! Good to see that your Coccinelle script has already done its magic! ;-)
Thanx, Paul
> --- > tools/perf/util/mmap.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > Hi, > > Would it be possible for this to be taken as a fixup in an upcoming rc? That > way we should be able to remove the ACCESS_ONCE() definitions prior to v4.15. > > Thanks, > Mark. > > diff --git a/tools/perf/util/mmap.h b/tools/perf/util/mmap.h > index efd78b827b05..3a5cb5a6e94a 100644 > --- a/tools/perf/util/mmap.h > +++ b/tools/perf/util/mmap.h > @@ -70,7 +70,7 @@ void perf_mmap__read_catchup(struct perf_mmap *md); > static inline u64 perf_mmap__read_head(struct perf_mmap *mm) > { > struct perf_event_mmap_page *pc = mm->base; > - u64 head = ACCESS_ONCE(pc->data_head); > + u64 head = READ_ONCE(pc->data_head); > rmb(); > return head; > } > -- > 2.11.0 >
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