On Sat, Aug 06, 2022 at 08:49:23AM +0200, Christophe JAILLET wrote:
Give a hint to the compiler that dev_err_probe() is used for error
handling. So calling paths are unlikely.
>From gcc documentation:
The paths leading to calls of cold functions within code are marked
as unlikely by the branch prediction mechanism.
Signed-off-by: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>
---
include/linux/device.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/device.h b/include/linux/device.h
index 424b55df0272..4ac16bde9bf7 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -1093,7 +1093,7 @@ void device_links_supplier_sync_state_pause(void);
void device_links_supplier_sync_state_resume(void);
extern __printf(3, 4)
-int dev_err_probe(const struct device *dev, int err, const char *fmt, ...);
+int __cold dev_err_probe(const struct device *dev, int err, const char *fmt, ...);
As the probe() path is by default "slow", does this actually help
anything? I never recommend using any sort of manual likely/unlikely
hints unless the results can be seen, otherwise the compiler and CPU
almost always do a better job over time.
thanks,
greg k-h