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From: Arnd Bergmann <arnd@arndb.de>
To: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: 'Paul Mundt' <lethal@linux-sh.org>,
	linux-kernel@vger.kernel.org, linux-fbdev@vger.kernel.org
Subject: Re: [PATCH] unicore32 framebuffer driver fix: make videomemory kmalloc-ed and floatable
Date: Wed, 30 Mar 2011 06:54:05 +0000	[thread overview]
Message-ID: <201103300854.05366.arnd@arndb.de> (raw)
In-Reply-To: <01ca01cbee7b$4f790370$ee6b0a50$@mprc.pku.edu.cn>

On Wednesday 30 March 2011 03:39:26 Guan Xuetao wrote:
> > How does this work? UNIFB_MEMSIZE seems to be 4 MB, much more than the
> > maximum of 128 KB that kmalloc can allocate.
> > 
> > Shouldn't this use get_free_pages() instead of kmalloc?
> > 
> 
> When using SLUB allocator, if required memory size  is larger
> than 2*PAGE_SIZE, kmalloc_large is called,
> and eventually __get_free_pages will  be called.
> So,  it would be the same as __get_free_pages.

Ok, I see. It's probably still better to use __get_free_pages directly,
because it's possible to select a different allocator that does not
do this itself.

	Arnd

WARNING: multiple messages have this Message-ID (diff)
From: Arnd Bergmann <arnd@arndb.de>
To: "Guan Xuetao" <gxt@mprc.pku.edu.cn>
Cc: "'Paul Mundt'" <lethal@linux-sh.org>,
	linux-kernel@vger.kernel.org, linux-fbdev@vger.kernel.org
Subject: Re: [PATCH] unicore32 framebuffer driver fix: make videomemory kmalloc-ed and floatable
Date: Wed, 30 Mar 2011 08:54:05 +0200	[thread overview]
Message-ID: <201103300854.05366.arnd@arndb.de> (raw)
In-Reply-To: <01ca01cbee7b$4f790370$ee6b0a50$@mprc.pku.edu.cn>

On Wednesday 30 March 2011 03:39:26 Guan Xuetao wrote:
> > How does this work? UNIFB_MEMSIZE seems to be 4 MB, much more than the
> > maximum of 128 KB that kmalloc can allocate.
> > 
> > Shouldn't this use get_free_pages() instead of kmalloc?
> > 
> 
> When using SLUB allocator, if required memory size  is larger
> than 2*PAGE_SIZE, kmalloc_large is called,
> and eventually __get_free_pages will  be called.
> So,  it would be the same as __get_free_pages.

Ok, I see. It's probably still better to use __get_free_pages directly,
because it's possible to select a different allocator that does not
do this itself.

	Arnd

  reply	other threads:[~2011-03-30  6:54 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-03-29 14:37 [PATCH] unicore32 framebuffer driver fix: make videomemory kmalloc-ed and floatable Guan Xuetao
2011-03-29 14:37 ` Guan Xuetao
2011-03-29 14:42 ` Arnd Bergmann
2011-03-29 14:42   ` Arnd Bergmann
2011-03-29 14:54   ` Guan Xuetao
2011-03-29 14:54     ` Guan Xuetao
2011-03-30  1:39   ` Guan Xuetao
2011-03-30  1:39     ` Guan Xuetao
2011-03-30  6:54     ` Arnd Bergmann [this message]
2011-03-30  6:54       ` Arnd Bergmann
2011-03-30  8:43       ` Guan Xuetao
2011-03-30  8:43         ` Guan Xuetao
2011-03-30 10:55         ` Arnd Bergmann
2011-03-30 10:55           ` Arnd Bergmann

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