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由 Mika Kuoppala 提交于
Not all architectures guarantee that uncached read will flush the write combining buffer. So marking it explicitly is recommended [1]. However we know the architecture we are operating on and can avoid wmb as the UC store will flush the wcb [2]. Omit the wmb() before invalidate as redudant. v2: squash combining and removal (Chris) v3: remove obsolete comments about posting reads (Chris) References: http://yarchive.net/comp/linux/write_combining.html [1] References: http://download.intel.com/design/PentiumII/applnots/24442201.pdf [2] Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Matthew Auld <matthew.auld@intel.com> Signed-off-by: NMika Kuoppala <mika.kuoppala@linux.intel.com> Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk> Link: https://patchwork.freedesktop.org/patch/msgid/20180508124154.14586-1-mika.kuoppala@linux.intel.com
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