Messages in this thread | | | Date | Wed, 28 Aug 2013 12:39:18 +0100 | From | Catalin Marinas <> | Subject | Re: [PATCH v4 2/4] ARM: Add atomic_io_modify optimized routines |
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On Wed, Aug 28, 2013 at 11:01:22AM +0100, Thomas Petazzoni wrote: > Dear Ezequiel Garcia, > > On Wed, 28 Aug 2013 06:49:08 -0300, Ezequiel Garcia wrote: > > > > Is this any different from the generic one introduced in patch 1/4? I > > > would rather just use the generic definition. > > > > Well, according to Will Deacon (and as documented in the commit log) > > we can optimize in ARM by using readl_relaxed instead of readl. > > > > Now, I'm sure you now better than me if that results (or not) in any > > significant optimization. > > > > > Similarly, a generic > > > atomic_io_modify_relaxed() but guarded with something like > > > __HAVE_ARCH_RELAXED_IO. > > > > > > > No, that's not possible. As far as I understand, there's no guarantee > > of _relaxed variants to be available architecture-wide. > > I think what Catalin was suggesting is that atomic_io_modify() should > use readl() and writel() (i.e *not* the relaxed variants), and that a > separate atomic_io_modify_relaxed() could be added on architectures > that define __HAVE_ARCH_RELAXED_IO. > > I think you misread Catalin's comment when you say there's no guarantee > of _relaxed variants to be available architecture-wide, since Catalin > precisely suggested to guard that with __HAVE_ARCH_RELAXED_IO, which > indicates that _relaxed variants are available.
Indeed, thanks for the translation ;).
-- Catalin
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