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From: Jeremy Fitzhardinge <jeremy@goop.org>
To: Avi Kivity <avi@qumranet.com>
Cc: Ingo Molnar <mingo@elte.hu>,
	Xen Devel <xen-devel@lists.xensource.com>,
	Andi Kleen <andi@firstfloor.org>,
	linux-kernel@vger.kernel.org, "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [Xen-devel] Re: [PATCH 1 of 7] x86: add _PAGE_IOMAP pte flag for IO	mappings
Date: Wed, 10 Sep 2008 09:38:36 -0700	[thread overview]
Message-ID: <48C7F80C.6000807@goop.org> (raw)
In-Reply-To: <48C7998D.1030408@qumranet.com>

Avi Kivity wrote:
> Actually it's more of a "no struct page" flag, which implies no
> refcounting.

Hm, is that actually true enough to define it?  Could we rename it
something like _PAGE_NOSTRUCTPAGE or something a bit more specific than
"special"?

>   And not having a struct page should correspond well to a pte not
> requiring pfn->mfn conversion and being an I/O page.

But _PAGE_SPECIAL is only set in a few places.  It's not set in ioremap
mappings and so on.  Should it be?

There's also the hiccup that it gets set in a pte with pte_mkspecial() -
but at that point its too late because you've already constructed the
pte and done the pfn->mfn conversion.  _PAGE_IOMAP can only be set when
you initially construct the pte out of a frame number and a pgprot.

    J

  reply	other threads:[~2008-09-10 16:38 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-09-07 22:21 [PATCH 0 of 7] x86: lay groundwork for Xen domain 0 support Jeremy Fitzhardinge
2008-09-07 22:21 ` [PATCH 1 of 7] x86: add _PAGE_IOMAP pte flag for IO mappings Jeremy Fitzhardinge
2008-09-09 13:32   ` Avi Kivity
2008-09-09 14:47     ` Jeremy Fitzhardinge
2008-09-09 14:56       ` Avi Kivity
2008-09-09 15:29         ` [Xen-devel] " Keir Fraser
2008-09-09 15:48           ` Jeremy Fitzhardinge
2008-09-09 16:05             ` Keir Fraser
2008-09-10  9:55         ` Avi Kivity
2008-09-10 16:38           ` Jeremy Fitzhardinge [this message]
2008-09-10 16:55             ` Nick Piggin
2008-09-10 17:27               ` Jeremy Fitzhardinge
2008-09-07 22:21 ` [PATCH 2 of 7] x86: remove duplicate early_ioremap declarations Jeremy Fitzhardinge
2008-09-07 22:21 ` [PATCH 3 of 7] x86: add early_memremap() Jeremy Fitzhardinge
2008-09-07 22:21 ` [PATCH 4 of 7] x86: use early_memremap() in setup.c Jeremy Fitzhardinge
2008-09-07 22:21 ` [PATCH 5 of 7] x86-64: don't check for map replacement Jeremy Fitzhardinge
2008-09-07 22:21 ` [PATCH 6 of 7] x86: use early_ioremap in __acpi_map_table Jeremy Fitzhardinge
2008-09-07 23:44   ` Andi Kleen
2008-09-08  0:03     ` Jeremy Fitzhardinge
2008-09-08 14:26       ` Ingo Molnar
2008-09-08 16:29         ` Jeremy Fitzhardinge
2008-09-08 19:41         ` Jeremy Fitzhardinge
2008-09-10 11:55         ` Ingo Molnar
2008-09-10 16:49           ` Jeremy Fitzhardinge
2008-09-11  7:33             ` Ingo Molnar
2008-09-11 18:36               ` Jeremy Fitzhardinge
2008-09-11 18:56                 ` Ingo Molnar
2008-09-11 20:34             ` Yinghai Lu
2008-09-11 21:07               ` Jeremy Fitzhardinge
2008-09-12  9:49                 ` Ingo Molnar
2008-09-12 17:31                   ` Yinghai Lu
     [not found]             ` <20080911125748.GA14698@elte.hu>
2008-09-11 21:33               ` [PATCH] acpi: remove final __acpi_map_table mapping before setting acpi_gbl_permanent_mmap Jeremy Fitzhardinge
2008-09-07 22:21 ` [PATCH 7 of 7] x86: always explicitly map acpi memory Jeremy Fitzhardinge
2008-09-07 23:35   ` [Xen-devel] " Yinghai Lu
2008-09-08  0:02     ` Jeremy Fitzhardinge
2008-09-08  0:14       ` Yinghai Lu

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