From: Adam Litke <agl@us.ibm.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: linux-mm@kvack.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC] Hugetlb demotion for x86
Date: Wed, 10 May 2006 15:32:36 -0500 [thread overview]
Message-ID: <1147293156.24029.95.camel@localhost.localdomain> (raw)
In-Reply-To: <20060510200516.GA30346@infradead.org>
On Wed, 2006-05-10 at 21:05 +0100, Christoph Hellwig wrote:
> On Wed, May 10, 2006 at 01:56:40PM -0500, Adam Litke wrote:
> > The following patch enables demotion of MAP_PRIVATE hugetlb memory to
> > normal anonymous memory on the i386 architecture.
>
> This is an awfully bad idea. Applications should do smart fallback
> instead. For the same reason we for example fail O_DIRECT requests
> we can fullfill instead of doing the half buffered I/O braindamage
> solaris does.
By smart fallback do you mean we should convert the hugetlb fault code
back to using VM_FAULT_SIGBUS and writing userspace sighandlers to do
the same thing I am, but in userspace? FWIW I did implement that in
libhugetlbfs to try it out, but that seems much dirtier to me than
handling faults in the kernel.
--
Adam Litke - (agl at us.ibm.com)
IBM Linux Technology Center
next prev parent reply other threads:[~2006-05-10 20:32 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-05-10 18:56 [RFC] Hugetlb demotion for x86 Adam Litke
2006-05-10 19:46 ` Dave Hansen
2006-05-10 19:49 ` Dave Hansen
2006-05-10 20:05 ` Christoph Hellwig
2006-05-10 20:32 ` Adam Litke [this message]
2006-05-10 20:49 ` Christoph Hellwig
2006-05-10 21:45 ` Adam Litke
2006-05-11 15:15 ` Hugh Dickins
2006-05-11 15:33 ` Alan Cox
2006-05-11 15:59 ` Adam Litke
2006-05-10 21:38 ` Andi Kleen
2006-05-10 23:42 ` Christoph Lameter
2006-05-11 16:10 ` Adam Litke
2006-05-15 14:20 ` Dave Hansen
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