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From: Muchun Song <smuchun@gmail.com>
To: gregkh@linuxfoundation.org, rafael@kernel.org
Cc: linux-kernel@vger.kernel.org
Subject: [PATCH] driver core: Add branch prediction hints in really_probe()
Date: Tue,  6 Nov 2018 21:46:30 +0800	[thread overview]
Message-ID: <20181106134630.29591-1-smuchun@gmail.com> (raw)

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 <smuchun@gmail.com>
---
 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


             reply	other threads:[~2018-11-06 13:47 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-06 13:46 Muchun Song [this message]
2018-11-06 14:30 ` [PATCH] driver core: Add branch prediction hints in really_probe() Rafael J. Wysocki
2018-11-06 14:43   ` Muchun Song
2018-11-06 14:59     ` Rafael J. Wysocki
2018-11-06 15:12       ` Muchun Song
2018-11-06 20:26 ` Greg KH

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