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| author | Peter Zijlstra <peterz@infradead.org> | 2013-10-31 20:25:38 +0400 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2013-11-06 15:34:20 +0400 |
| commit | 85f59edf9684603026c64c902791748116d29478 (patch) | |
| tree | 13da84a3f347a24a3929d7546a6d7e9addbdf857 /kernel/pid_namespace.c | |
| parent | c72b42a3dde487132da80202756c101b371b2add (diff) | |
| download | linux-85f59edf9684603026c64c902791748116d29478.tar.xz | |
perf: Optimize perf_output_begin()
There's no point in re-doing the memory-barrier when we fail the
cmpxchg(). Also placing it after the space reservation loop makes it
clearer it only separates the userpage->tail read from the data
stores.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Michael Ellerman <michael@ellerman.id.au>
Cc: Michael Neuling <mikey@neuling.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: james.hogan@imgtec.com
Cc: Vince Weaver <vince@deater.net>
Cc: Victor Kaplansky <VICTORK@il.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Anton Blanchard <anton@samba.org>
Link: http://lkml.kernel.org/n/tip-c19u6egfldyx86tpyc3zgkw9@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/pid_namespace.c')
0 files changed, 0 insertions, 0 deletions