On Tue, Nov 6, 2018 at 2:47 PM Muchun Song <[email protected]> wrote:
>
> If condition is false in most cases. So, add an unlikely() to the if
> condition, so that the optimizer assumes that the condition is false.
>
> Signed-off-by: Muchun Song <[email protected]>
Have you measured the practical impact of this patch in any way?
> ---
> drivers/base/dd.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/base/dd.c b/drivers/base/dd.c
> index 169412ee4ae8..8eba453c4e5d 100644
> --- a/drivers/base/dd.c
> +++ b/drivers/base/dd.c
> @@ -450,7 +450,7 @@ static int really_probe(struct device *dev, struct
> device_driver *drv)
> bool test_remove = IS_ENABLED(CONFIG_DEBUG_TEST_DRIVER_REMOVE) &&
> !drv->suppress_bind_attrs;
>
> - if (defer_all_probes) {
> + if (unlikely(defer_all_probes)) {
> /*
> * Value of defer_all_probes can be set only by
> * device_defer_all_probes_enable() which, in turn, will call
> @@ -508,7 +508,7 @@ static int really_probe(struct device *dev, struct
> device_driver *drv)
> goto probe_failed;
> }
>
> - if (test_remove) {
> + if (unlikely(test_remove)) {
> test_remove = false;
>
> if (dev->bus->remove)
> --
> 2.17.1
>
