Frederic Weisbecker 2d4d57db69 x86: micro-optimize __raw_read_trylock() ...

The current version of __raw_read_trylock starts with decrementing the lock
and read its new value as a separate operation after that.

That makes 3 dereferences (read, write (after sub), read) whereas
a single atomic_dec_return does only two pointers dereferences (read, write).

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

2009-01-26 14:06:36 +01:00

..

asm

x86: micro-optimize __raw_read_trylock()

2009-01-26 14:06:36 +01:00