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Date: Wed, 27 Aug 2014 14:30:55 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Christoph Lameter <cl@linux.com>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>, linux-fsdevel@vger.kernel.org,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        willy@linux.intel.com
Subject: Re: [PATCH v10 00/21] Support ext4 on NV-DIMMs
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On Wed, 27 Aug 2014 16:22:20 -0500 (CDT) Christoph Lameter <cl@linux.com> wrote:

> > Some explanation of why one would use ext4 instead of, say,
> > suitably-modified ramfs/tmpfs/rd/etc?
> 
> The NVDIMM contents survive reboot and therefore ramfs and friends wont
> work with it.

See "suitably modified".  Presumably this type of memory would need to
come from a particular page allocator zone.  ramfs would be unweildy
due to its use to dentry/inode caches, but rd/etc should be feasible.

I dunno, I'm not proposing implementations - I'm asking obvious
questions.  Stuff which should have been addressed in the changelogs
before one even starts to read the code...