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From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: moreau francis <francis_moreau2000@yahoo.fr>
Cc: linux-kernel@vger.kernel.org, apw@shadowen.org
Subject: Re: sparsemem usage
Date: Wed, 02 Aug 2006 16:24:40 +0100	[thread overview]
Message-ID: <1154532280.23655.23.camel@localhost.localdomain> (raw)
In-Reply-To: <20060802134413.63901.qmail@web25814.mail.ukl.yahoo.com>

Ar Mer, 2006-08-02 am 13:44 +0000, ysgrifennodd moreau francis:
> #if (MAX_ORDER - 1 + PAGE_SHIFT) > SECTION_SIZE_BITS
> #error Allocator MAX_ORDER exceeds SECTION_SIZE
> #endif
> 
> I'm not sure to understand why there's such check. To fix this
> I should change MAX_ORDER to 6.
> 
> Is it the only way to fix that ?

The kernel allocates memory out using groups of blocks in a buddy
system. 128K is smaller than one of the blocks so the kernel cannot
handle this. You need 2MB (if I remember right) granularity for your
sections but nothing stops you marking most of the 2Mb section except
the 128K that exists as "in use"

Alan


  parent reply	other threads:[~2006-08-02 15:05 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-08-02 13:44 sparsemem usage moreau francis
2006-08-02 14:25 ` Andy Whitcroft
2006-08-02 15:12   ` Re : " moreau francis
2006-08-02 15:36     ` Andy Whitcroft
2006-08-03  9:56       ` Re : " moreau francis
2006-08-02 15:24 ` Alan Cox [this message]
2006-08-02 15:33   ` moreau francis
2006-08-02 16:33     ` Alan Cox

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