From: Gerd Hoffmann <kraxel@suse.de>
To: Jan Beulich <jbeulich@novell.com>
Cc: xen-devel@lists.xensource.com
Subject: Re: using PageForeign for pte allocation vs. shortcutting __pte_free_tlb()
Date: Tue, 09 Jan 2007 12:11:42 +0100 [thread overview]
Message-ID: <45A3786E.8090309@suse.de> (raw)
In-Reply-To: <45A3836D.76E4.0078.0@novell.com>
Jan Beulich wrote:
>>>> Gerd Hoffmann <kraxel@suse.de> 09.01.07 11:51 >>>
>> Jan Beulich wrote:
>>> In the course of trying to get CONFIG_HIGHPTE to work I stumbled across this
>>> inconsistency between i386 and x86-64 Linux: i386 uses SetPageForeign() in
>>> (one the non-highpte) case of pte_alloc_one(), and leaves intact native's
>>> definition of __pte_free_tlb(), whereas x86-64 doesn't use the former but
>>> shortcuts the latter to just invoke pte_free(). Obviously it would be nice for
>>> these two to be consistent,
>> x86-64 has no HIGHMEM zone, thus CONFIG_HIGHPTE has no effect (I'm
>> surprised it exists in the first place ...).
>
> Of course (and no, such a config option doesn't exist for x86-64), but what
> relation does this have to the question asked?
guess (not having looked at the code at all) i386 does that because it
needs disturgish high and non-high ptes, whereas x86-64 simply has no
need for that, so I don't see the point in trying to make them
consistent ...
cheers,
Gerd
--
Gerd Hoffmann <kraxel@suse.de>
next prev parent reply other threads:[~2007-01-09 11:11 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-01-09 10:21 using PageForeign for pte allocation vs. shortcutting __pte_free_tlb() Jan Beulich
2007-01-09 10:51 ` Gerd Hoffmann
2007-01-09 10:58 ` Jan Beulich
2007-01-09 11:11 ` Gerd Hoffmann [this message]
2007-01-09 11:27 ` Jan Beulich
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