Subject: Re: [PATCH -v7 0/35] tip related: not use  bootmem for x86
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Yinghai Lu <yinghai@kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>, Thomas Gleixner <tglx@linutronix.de>,
       "H. Peter Anvin" <hpa@zytor.com>,
       Andrew Morton <akpm@linux-foundation.org>,
       Linus Torvalds <torvalds@linux-foundation.org>,
       Jesse Barnes <jbarnes@virtuousgeek.org>,
       Christoph Lameter <cl@linux-foundation.org>,
       linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org
In-Reply-To: <1265793639-15071-1-git-send-email-yinghai@kernel.org>
References: <1265793639-15071-1-git-send-email-yinghai@kernel.org>
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Date: Mon, 15 Feb 2010 13:27:26 +1100
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On Wed, 2010-02-10 at 01:20 -0800, Yinghai Lu wrote:
> 
> The reserve_early() method is list/range based and can handle vast
> amounts of not very fragmented memory - perfect for basically all the
> real bootmem purposes (which is to bootstrap the buddy).
> 
> reserve_early() allocated memory could be freed into the buddy later
> on
> as well. The main reason why bootmem is 'destroyed' during
> free-to-buddy
> is because it has excessive internal bitmaps we want to free. With a
> list/range based reserve_early() mechanism there's no such problem -
> they can linger indefinitely and there's near zero allocation
> management
> overhead. " 

Various archs use lib/lmb.c for representing physical memory and
doing early allocations. Might be something to extend ?

Cheers,
Ben.


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