From: "Luck, Tony" <tony.luck@intel.com>
To: Linus Torvalds <torvalds@linux-foundation.org>,
linux-kernel@vger.kernel.org
Subject: [PATCH] lockref: Relax in cmpxchg loop
Date: Tue, 3 Sep 2013 14:49:49 -0700 [thread overview]
Message-ID: <0129530@agluck-desk.sc.intel.com> (raw)
While we are likley to succeed and break out of this loop, it isn't
guaranteed. We should be power and thread friendly if we do have to
go around for a second (or third, or more) attempt.
Signed-off-by: Tony Luck <tony.luck@intel.com>
---
diff --git a/lib/lockref.c b/lib/lockref.c
index 7819c2d..9d76f40 100644
--- a/lib/lockref.c
+++ b/lib/lockref.c
@@ -19,6 +19,7 @@
if (likely(old.lock_count == prev.lock_count)) { \
SUCCESS; \
} \
+ cpu_relax(); \
} \
} while (0)
--
1.8.1.4
reply other threads:[~2013-09-03 22:01 UTC|newest]
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