[PATCH] Documentation: improvement to volatile considered harmful (resubmit)

[PATCH] Documentation: improvement to volatile considered harmful (resubmit)

[Heikki Orsila]

I'm resubmitting this as I didn't get any replies, this time CCeing 
proper people, sorry..

Kernel locking/synchronization primitives are better than volatile types 
from code readability point of view also.

This patch is against 2.6.22-rc6.

Signed-off-by: Heikki Orsila <heikki.orsila@iki.fi>

diff --git a/Documentation/volatile-considered-harmful.txt b/Documentation/volatile-considered-harmful.txt
index 10c2e41..ab9e62e 100644
--- a/Documentation/volatile-considered-harmful.txt
+++ b/Documentation/volatile-considered-harmful.txt
@@ -17,8 +17,9 @@ all optimization-related problems in a more efficient way.
 
 Like volatile, the kernel primitives which make concurrent access to data
 safe (spinlocks, mutexes, memory barriers, etc.) are designed to prevent
-unwanted optimization.  If they are being used properly, there will be no
-need to use volatile as well.  If volatile is still necessary, there is
+unwanted optimization. If they are being used properly, there will be no
+need to use volatile as well. Also, they make code more readable as they
+represent their intent explicitly. If volatile is still necessary, there is
 almost certainly a bug in the code somewhere.  In properly-written kernel
 code, volatile can only serve to slow things down.
 

-- 
Heikki Orsila			Barbie's law:
heikki.orsila@iki.fi		"Math is hard, let's go shopping!"
http://www.iki.fi/shd

Re: [PATCH] Documentation: improvement to volatile considered harmful (resubmit)

[Jonathan Corbet]

Heikki Orsila <shdl@zakalwe.fi> wrote:

> I'm resubmitting this as I didn't get any replies, this time CCeing 
> proper people, sorry..
> 
> Kernel locking/synchronization primitives are better than volatile types 
> from code readability point of view also.

I think that just dilutes the real point.  It's not a choice between
locking and volatile - the locking must be there regardless.  It's a
correctness issue; if the result happens to be more readable too that's
a bonus.

If somebody wants to put this sentence in I won't object, but I don't
think it really improves the document either.

Thanks,

jon