From: "H. Peter Anvin" <hpa@zytor.com>
To: "Robert P. J. Day" <rpjday@mindspring.com>
Cc: Satyam Sharma <satyam.sharma@gmail.com>,
Nick Piggin <nickpiggin@yahoo.com.au>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Ralf Baechle <ralf@linux-mips.org>
Subject: Re: why does the macro "ZERO_PAGE" take an argument?
Date: Thu, 07 Jun 2007 10:32:29 -0700 [thread overview]
Message-ID: <4668412D.3030506@zytor.com> (raw)
In-Reply-To: <Pine.LNX.4.64.0706070750540.16051@localhost.localdomain>
Robert P. J. Day wrote:
>> The comment above empty_zero_page and zero_page_mask
>> declarations at arch/mips/mm/init.c:508 sheds light on this ...
>
> well, it *sort of* does. at line 64 of that file:
>
> /*
> * We have up to 8 empty zeroed pages so we can map one of the right colour
> * when needed. This is necessary only on R4000 / R4400 SC and MC versions
> * where we have to avoid VCED / VECI exceptions for good performance at
> * any price. Since page is never written to after the initialization we
> * don't have to care about aliases on other CPUs.
> */
>
> although it's not clear where in the source tree are the invocations
> that would actually make a difference to a MIPS system, which is why
> i've CC'ed ralf on this. i'm sure he can clear this up. :-)
x86 could also benefit from coloured zeropages. In fact, I thought it
already had them (K8 wants as many as 8.)
-hpa
next prev parent reply other threads:[~2007-06-07 17:39 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-06-07 11:17 why does the macro "ZERO_PAGE" take an argument? Robert P. J. Day
2007-06-07 11:29 ` Nick Piggin
2007-06-07 11:34 ` Robert P. J. Day
2007-06-07 11:39 ` Satyam Sharma
2007-06-07 11:53 ` Robert P. J. Day
2007-06-07 16:37 ` Ralf Baechle
2007-06-07 18:04 ` H. Peter Anvin
2007-06-07 17:32 ` H. Peter Anvin [this message]
2007-06-07 19:29 ` William Lee Irwin III
2007-06-07 21:16 ` H. Peter Anvin
2007-06-08 7:25 ` Robert P. J. Day
2007-06-09 0:49 ` H. Peter Anvin
2007-06-12 2:18 ` Nick Piggin
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