diff options
| author | Eric Dumazet <eric.dumazet@gmail.com> | 2011-03-28 18:06:58 +0200 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2011-03-28 18:06:58 +0200 |
| commit | 5f55924deaa62d6df687c131fb92aebe071ec787 (patch) | |
| tree | 2888f5163793d9b37ff6726e470853d5d727abe3 /drivers/media/video/gspca/mr97310a.c | |
| parent | percpu: Cast away printk format warning (diff) | |
| download | linux-5f55924deaa62d6df687c131fb92aebe071ec787.tar.xz linux-5f55924deaa62d6df687c131fb92aebe071ec787.zip | |
percpu: Avoid extra NOP in percpu_cmpxchg16b_double
percpu_cmpxchg16b_double() uses alternative_io() and looks like :
e8 .. .. .. .. call this_cpu_cmpxchg16b_emu
X bytes NOPX
or, once patched (if cpu supports native instruction) on SMP build :
65 48 0f c7 0e cmpxchg16b %gs:(%rsi)
0f 94 c0 sete %al
on !SMP build :
48 0f c7 0e cmpxchg16b (%rsi)
0f 94 c0 sete %al
Therefore, NOPX should be :
P6_NOP3 on SMP
P6_NOP2 on !SMP
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'drivers/media/video/gspca/mr97310a.c')
0 files changed, 0 insertions, 0 deletions