lkml.org 
[lkml]   [2002]   [Jul]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [BK PATCH 2.5] Introduce 64-bit versions of PAGE_{CACHE_,}{MASK,ALIGN}
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

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:27    [W:0.278 / U:0.236 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site