From: "Grant Likely" <grant.likely@secretlab.ca>
To: "Josh Boyer" <jwboyer@gmail.com>
Cc: chretien@enseirb.fr, linuxppc-dev@ozlabs.org
Subject: Re: ioremap and vmalloc
Date: Fri, 19 Sep 2008 11:12:22 -0600 [thread overview]
Message-ID: <fa686aa40809191012q76d1c450ye12094ac63bc68a7@mail.gmail.com> (raw)
In-Reply-To: <20080919165833.GD4492@yoda.jdub.homelinux.org>
On Fri, Sep 19, 2008 at 10:58 AM, Josh Boyer <jwboyer@gmail.com> wrote:
> On Fri, Sep 19, 2008 at 06:45:01PM +0200, =?ISO-8859-1?Q?S=E9bastien_Chr=E9tien_ wrote:
>> if I write :
>> ioremap(0x20000000,0x40000) and ioremap(0x20000000,0x50000)
>>
>> Will it crash ?
>
> I have no idea. You haven't given us enough information to really answer
> that.
But I can say that the second ioremap() call makes the first ioremap()
both redundant and inefficient. You're using exactly the same base
address so the same region is getting mapped twice. Since the second
call uses a bigger region than the first then the kernel will probably
need to allocate another chunk of virtual address space to map it
instead of reusing the first mapping.
g.
--
Grant Likely, B.Sc., P.Eng.
Secret Lab Technologies Ltd.
next prev parent reply other threads:[~2008-09-19 17:12 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-09-19 11:15 ioremap and vmalloc Sébastien Chrétien
2008-09-19 13:49 ` Grant Likely
2008-09-19 16:34 ` Sébastien Chrétien
2008-09-19 16:38 ` Josh Boyer
2008-09-19 16:45 ` Sébastien Chrétien
2008-09-19 16:58 ` Josh Boyer
2008-09-19 17:12 ` Grant Likely [this message]
2008-09-19 17:47 ` Sébastien Chrétien
2008-09-19 17:52 ` Sébastien Chrétien
2008-09-22 5:28 ` Benjamin Herrenschmidt
2008-09-19 16:43 ` Grant Likely
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