Message-ID: <51C9E523.7000803@zytor.com>
Date: Tue, 25 Jun 2013 11:44:51 -0700
From: "H. Peter Anvin" <hpa@zytor.com>
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To: Yinghai Lu <yinghai@kernel.org>
CC: Mike Travis <travis@sgi.com>, Greg KH <gregkh@linuxfoundation.org>,
        Nathan Zimmer <nzimmer@sgi.com>, Robin Holt <holt@sgi.com>,
        Rob Landley <rob@landley.net>, Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        the arch/x86 maintainers <x86@kernel.org>, linux-doc@vger.kernel.org,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [RFC 0/2] Delay initializing of large sections of memory
References: <1371831934-156971-1-git-send-email-nzimmer@sgi.com> <20130621165142.GA32125@kroah.com> <51C48745.9030304@zytor.com> <CAE9FiQX3Opcv0E7+PXNAUoJtgoa0Cxv5wOK=R_ERvQjN79poXQ@mail.gmail.com> <20130621185056.GA23473@kroah.com> <51C4C5F3.3050800@sgi.com> <CAE9FiQXaUNbK9+g-7j6gfvLrSvUJFWWKapDv658LPe4VfbH=tQ@mail.gmail.com> <51C9D4ED.5070805@sgi.com> <51C9DEC1.6030602@zytor.com> <CAE9FiQV5z+3AXy5c=aaU3vq1V3fibJ6PhhA4VW5H8BWVzhxXPA@mail.gmail.com>
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On 06/25/2013 11:40 AM, Yinghai Lu wrote:
> On Tue, Jun 25, 2013 at 11:17 AM, H. Peter Anvin <hpa@zytor.com> wrote:
>> On 06/25/2013 10:35 AM, Mike Travis wrote:
> 
>> However, please consider Ingo's counterproposal of doing this via the
>> buddy allocator, i.e. hugepages being broken on demand.  That is a
>> *very* powerful model, although would require more infrastructure.
> 
> Can you or Ingo elaborate more about the buddy allocator proposal?
> 

Start by initializing 1G hyperpages only, but mark them so that the
allocator knows that if it needs to break them apart it has to
initialize the page structures for the 2M subpages.

Same thing with 2M -> 4K.

	-hpa


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