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From: Matthew Wilcox <willy@linux.intel.com>
To: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Jan Kara <jack@suse.cz>,
	linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
	lsf-pc@lists.linux-foundation.org
Subject: Re: [Lsf-pc] [LSF/MM TOPIC] Support for 1GB THP
Date: Wed, 2 Mar 2016 09:14:26 -0500	[thread overview]
Message-ID: <20160302141426.GM3730@linux.intel.com> (raw)
In-Reply-To: <1456871764.2369.59.camel@HansenPartnership.com>

On Tue, Mar 01, 2016 at 02:36:04PM -0800, James Bottomley wrote:
> On Tue, 2016-03-01 at 16:44 -0500, Matthew Wilcox wrote:
> > I think it's both.  I heard from one customer who calculated that 
> > with a 6TB server, mapping every page into a process would take ~24MB 
> > of page tables.  Multiply that by the 50,000 processes they expect to
> > run on a server of that size consumes 1.2TB of DRAM.  Using 1GB pages
> > reduces that by a factor of 512, down to 2GB.
> 
> This sounds a bit implausible:

Well, that's the customer workload.  They have terabytes of data, and they
want to map all of it into all 50k processes.  I know it's not how I use
my machine, but that's customers for you ...

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  reply	other threads:[~2016-03-02 14:14 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-03-01  7:09 [LSF/MM TOPIC] Support for 1GB THP Matthew Wilcox
2016-03-01 10:25 ` [Lsf-pc] " Jan Kara
2016-03-01 11:00   ` Mel Gorman
2016-03-01 11:51     ` Mel Gorman
2016-03-01 12:09       ` Kirill A. Shutemov
2016-03-01 12:52         ` Mel Gorman
2016-03-01 21:44   ` Matthew Wilcox
2016-03-01 22:15     ` Mike Kravetz
2016-03-01 22:33     ` Rik van Riel
2016-03-01 22:36     ` James Bottomley
2016-03-02 14:14       ` Matthew Wilcox [this message]
2016-03-01 12:20 ` Kirill A. Shutemov
2016-03-01 16:32   ` Christoph Lameter
2016-03-01 21:47     ` Matthew Wilcox

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