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From: Russell King on 9 Mar 2010 11:40
Subject: Correct cpu_relax() documentation

cpu_relax() is documented in volatile-considered-harmful.txt to be a
memory barrier. However, everyone with the exception of Blackfin and
possibly ia64 defines cpu_relax() to be a compiler barrier.

Make the documentation reflect the general concensus.

Signed-off-by: Russell King <rmk+kernel(a)arm.linux.org.uk>
---
Documentation/volatile-considered-harmful.txt | 6 +++---
1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/Documentation/volatile-considered-harmful.txt b/Documentation/volatile-considered-harmful.txt
index 991c26a..db0cb22 100644
--- a/Documentation/volatile-considered-harmful.txt
+++ b/Documentation/volatile-considered-harmful.txt
@@ -63,9 +63,9 @@ way to perform a busy wait is:
cpu_relax();

The cpu_relax() call can lower CPU power consumption or yield to a
-hyperthreaded twin processor; it also happens to serve as a memory barrier,
-so, once again, volatile is unnecessary. Of course, busy-waiting is
-generally an anti-social act to begin with.
+hyperthreaded twin processor; it also happens to serve as a compiler
+barrier, so, once again, volatile is unnecessary. Of course, busy-
+waiting is generally an anti-social act to begin with.

There are still a few rare situations where volatile makes sense in the
kernel:


--
Russell King
Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/
maintainer of:
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