linux-kernel - Re: bitmap?_find_free_region and bitmap

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Date:	Fri, 1 Dec 2006 09:42:29 +0900
From:	Paul Mundt <lethal@...ux-sh.org>
To:	Paul Jackson <pj@....com>
Cc:	Komal Shah <komal.shah802003@...il.com>,
	"M. R. Brown" <mrbrown@...6.org>, linux-kernel@...r.kernel.org,
	akpm@...l.org
Subject: Re: bitmap?_find_free_region and bitmap_full arg doubts

On Thu, Nov 30, 2006 at 04:10:08PM -0800, Paul Jackson wrote:
> The call to bitmap_find_free_region(), in arch/sh/kernel/cpu/sh4/sq.c
> looks bogus:
> 
>         page = bitmap_find_free_region(sq_bitmap, 0x04000000,
>                                        get_order(map->size));
> 
> It says the bitmap has 0x04000000 bits.  This would take 0x04000000 / 8
> which is 8388608 (decimal) bytes to hold.  That's an insanely
> huge bitmap - 8 million bytes worth of bits.
> 
Ouch, you're right, for some reason we missed the >> PAGE_SHIFT here,
even though it was handled properly in sq_api_init(). I suppose we
haven't hit this in practice as most of the users end up being quite
small. I'll fix it up. Good catch, thanks!
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