Messages in this thread | | | From | Jianyu Zhan <> | Date | Wed, 2 Mar 2016 21:56:32 +0800 | Subject | Re: [PATCH v2] futex: replace bare barrier() with a READ_ONCE() |
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On Wed, Mar 2, 2016 at 9:35 PM, Christian Borntraeger <borntraeger@de.ibm.com> wrote: > That change makes sense. I did the original barrier back in 2006 (could you cc me next time?)
Sorry for that, I thought get_maintainer.pl would had spit the original author's email, but apparently it didn't :(
> ACCESS_ONCE or READ_ONCE was not available at that time and its now the better way. > > This is not an s390 specific problem, it was just triggered there as the gcc cost model > considered the memory read as cheap as a register read. >
Thanks for the clarification.
> Maybe simplify the comment to something like > > /* Prevent the compiler to read lock_ptr twice (if and spin_lock) */
Will do.
Regards, Jianyu Zhan
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