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Subject: Re: [PATCH RFC] hugetlbfs 'noautofill' mount option
To: Prakash Sangappa <prakash.sangappa@oracle.com>,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org
References: <326e38dd-b4a8-e0ca-6ff7-af60e8045c74@oracle.com>
 <b0efc671-0d7a-0aef-5646-a635478c31b0@oracle.com>
From: Dave Hansen <dave.hansen@intel.com>
Message-ID: <7ff6fb32-7d16-af4f-d9d5-698ab7e9e14b@intel.com>
Date: Tue, 2 May 2017 14:32:42 -0700
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On 05/01/2017 11:00 AM, Prakash Sangappa wrote:
> This patch adds a new hugetlbfs mount option 'noautofill', to indicate that
> pages should not be allocated at page fault time when accessed thru mmapped
> address.

I think the main argument against doing something like this is further
specializing hugetlbfs.  I was really hoping that userfaultfd would be
usable for your needs here.

Could you elaborate on other options that you considered?  Did you look
at userfaultfd?  What about an madvise() option that disallows backing
allocations?