On Fri, Jun 21, 2013 at 06:17:21PM +0100, Will Deacon wrote:
> This is an RFC cleanup series removing the unused
> arch_{spin,read,write}_relax macros from (nearly) all architectures that
> define them. The macros have no users in core code and are typically
> synonymous with cpu_relax(), the notable exceptions being PowerPC (where
> the thing is still unused) and S390.
So the `no users in core code' part isn't quite true...
With GENERIC_LOCKBREAK (arm64, ia64, m32r, parisc, powerpc, s390, sh and
sparc), we can actually spit out arch_*_relax calls in kernel/spinlock.c
using some macro concatenation that defeated my grep-fu.
This only makes a difference on powerpc and s390, so we could either:
(1) conditionally define the relax macros as cpu_relax in spinlock.c (so
the two guys above can have their special versions)
(2) Replace the calls with calls to cpu_relax() (although powerpc seems to
want to know who owns the lock in order to relax)
(3) Leave the current code alone for architectures that may select
GENERIC_LOCKBREAK
Any other ideas/preferences?
Will
--
To unsubscribe from this list: send the line "unsubscribe linux-arch" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
