Messages in this thread | | | Date | Mon, 29 Jul 2002 10:27:21 +0100 | From | Russell King <> | Subject | Re: [BK PATCH 2.5] Introduce 64-bit versions of PAGE_{CACHE_,}{MASK,ALIGN} |
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On Sun, Jul 28, 2002 at 05:10:48PM -0700, Andrew Morton wrote: > - Remove ->virtual, do page_address() via a hash. 4(ish) bytes saved.
Hmmmmmmm. page_address() is already 5 loads (on ARM) if page->virtual isn't used. I'm seriously considering changing page_address() to cover the 3 cases more efficiently:
1. non-discontiguous case (should be around 2 loads + math) 2. discontiguous case (currently 5 loads + lots of math) 3. weirder setups where loading page->virtual is faster
We currently ignore (1) completely, and just assume its the same as (2).
-- Russell King (rmk@arm.linux.org.uk) The developer of ARM Linux http://www.arm.linux.org.uk/personal/aboutme.html
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