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From: Russell King <rmk@arm.linux.org.uk>
To: Andrew Morton <akpm@zip.com.au>
Cc: Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: [BK PATCH 2.5] Introduce 64-bit versions of PAGE_{CACHE_,}{MASK,ALIGN}
Date: Mon, 29 Jul 2002 10:27:21 +0100	[thread overview]
Message-ID: <20020729102721.B23843@flint.arm.linux.org.uk> (raw)
In-Reply-To: <3D448808.CF8D18BA@zip.com.au>; from akpm@zip.com.au on Sun, Jul 28, 2002 at 05:10:48PM -0700

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


  parent reply	other threads:[~2002-07-29  9:24 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-07-27 13:41 [BK PATCH 2.5] Introduce 64-bit versions of PAGE_{CACHE_,}{MASK,ALIGN} Anton Altaparmakov
2002-07-27 17:23 ` Andrew Morton
2002-07-28 17:53   ` Eric W. Biederman
2002-07-28 18:54     ` Anton Altaparmakov
2002-07-28 20:12       ` Eric W. Biederman
2002-07-28 23:26       ` Linus Torvalds
2002-07-29  0:10         ` Andrew Morton
2002-07-29  0:43           ` William Lee Irwin III
2002-07-29  0:56             ` Andrea Arcangeli
2002-07-29  1:04               ` William Lee Irwin III
2002-07-29  1:09               ` Rik van Riel
2002-07-29  2:14                 ` Andrew Morton
2002-07-29  2:11                   ` William Lee Irwin III
2002-07-29  2:18                   ` Rik van Riel
2002-07-29  0:49           ` Andrea Arcangeli
2002-07-29  2:05             ` Andrew Morton
2002-07-29  2:09               ` William Lee Irwin III
2002-07-29 20:52               ` Andrea Arcangeli
2002-07-29 21:01                 ` Andrew Morton
2002-07-29 21:31                   ` Andrea Arcangeli
2002-07-29 21:46                     ` Andrew Morton
2002-07-29 22:18                       ` Andrea Arcangeli
2002-07-29  0:56           ` William Lee Irwin III
2002-07-29  1:36             ` Andrew Morton
2002-07-29  1:37               ` William Lee Irwin III
2002-07-29  9:27           ` Russell King [this message]
2002-07-29 18:32             ` Andrew Morton
     [not found] <5.1.0.14.2.20020728193528.04336a80@pop.cus.cam.ac.uk.suse.lists.linux.kernel>
     [not found] ` <Pine.LNX.4.44.0207281622350.8208-100000@home.transmeta.com.suse.lists.linux.kernel>
     [not found]   ` <3D448808.CF8D18BA@zip.com.au.suse.lists.linux.kernel>
     [not found]     ` <20020729004942.GL1201@dualathlon.random.suse.lists.linux.kernel>
     [not found]       ` <3D44A2DF.F751B564@zip.com.au.suse.lists.linux.kernel>
     [not found]         ` <20020729205211.GB1201@dualathlon.random.suse.lists.linux.kernel>
2002-07-30 13:44           ` Andi Kleen
2002-07-30 14:06             ` Rik van Riel

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