Message-ID: <5493D9CE.5040001@lge.com>
Date: Fri, 19 Dec 2014 16:54:54 +0900
From: Gioh Kim <gioh.kim@lge.com>
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To: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        dri-devel@lists.freedesktop.org,
        =?EUC-KR?B?wMywx8ij?= <gunho.lee@lge.com>,
        Minchan Kim <minchan@kernel.org>,
        =?EUC-KR?B?J7Howdg=?= =?EUC-KR?B?vPYn?= <iamjoonsoo.kim@lge.com>
Subject: [RFC] background zero-set page for device
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There was some discussion to create zero-set pages in background like this:
https://lkml.org/lkml/2004/10/30/73

I'm understand that it is not good for performance.

But I think it can help for a device in my platform.
I'm sorry I can't tell what it is.
But the device needs many zero-set pages, up to several MB,
so that device driver has a loop to calls alloc_page, memset(p, 0, PAGE_SIZE) and cache flush&invalidate.
And the device uses the pages and returns it to kernel. Kernel reads data in the page.

In this case, memset(0) must be done.
I think, if memset(0) is done at idle time, it can remove memset calling of ddk.

Is there any device that needs many zero-set pages?
Can backgound zero-setting page be good for the device?

-- 
Thanks,
Gioh Kim
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