From: Arnd Bergmann <arnd@arndb.de>
To: linuxppc-dev@ozlabs.org
Cc: Paul Mackerras <paulus@samba.org>, Christoph Hellwig <hch@lst.de>,
linux-kernel@vger.kernel.org
Subject: Re: [RFC][POWERPC] Provide a way to protect 4k subpages when using 64k pages
Date: Tue, 11 Dec 2007 22:21:15 +0100 [thread overview]
Message-ID: <200712112221.17697.arnd@arndb.de> (raw)
In-Reply-To: <20071211155305.GA28055@lst.de>
On Tuesday 11 December 2007, Christoph Hellwig wrote:
> Using 4k pages should basically be a pre-process flag
> (which it already is as an implementation detail in your patch), and
> thus the proper way to mark it should be a personality flag. =A0This
> also means it could be implied by certain personalities, e.g. powerpc
> 32bit for full compatiblity. =A0 All these process would use plain mmap/
> mprotect to deal with the subpage protections.
If you want to make it a per-process flag, wouldn't a prctl bit be more
appropriate than a personality flag? That way you could at least set
it independent from other personality settings.
> At least ia64 and mips have multiple pages sizes already and I suspect
> more architectures will grow support for it.
Another related option might be the alternative page table layouts that
Martin Schwidefsky has implemented for concurrent 2/3/4-level page tables
on s390.
Arnd <><
next prev parent reply other threads:[~2007-12-11 21:21 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-12-07 6:09 [RFC][POWERPC] Provide a way to protect 4k subpages when using 64k pages Paul Mackerras
2007-12-07 12:03 ` Arnd Bergmann
2007-12-11 15:53 ` Christoph Hellwig
2007-12-11 21:21 ` Arnd Bergmann [this message]
2007-12-11 21:37 ` Paul Mackerras
2007-12-11 23:38 ` Benjamin Herrenschmidt
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