Re: [PATCH v4 2/3] mm/page_alloc.c: add config option to sanitize freed pages

[Anisse Astier]

On Tue, May 19, 2015 at 3:58 AM, yalin wang <yalin.wang2010@xxxxxxxxx> wrote:
> 2015-05-18 21:04 GMT+08:00 Anisse Astier <anisse@xxxxxxxxx>:
>> On Mon, May 18, 2015 at 3:02 PM, Pavel Machek <pavel@xxxxxx> wrote:
>>>
>>> Ok. So there is class of errors where this helps, but you are not
>>> aware of any such errors in kernel, so you can't fix them... Right?
>>
>> Correct.
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> i feel your patch is the same as CONFIG_DEBUG_PAGEALLOC ,
> the difference is that CONFIG_DEBUG_PAGEALLOC  will clear
> page to a magic number, while your patch will
> clear to zero,
> do we really need this duplicated function ?

It's different because DEBUG_PAGEALLOC will only use page poisoning on
certain architectures, and clearing a page to a magic number doesn't
allow to optimize alloc with _GFP_ZERO.

Regards,

Anisse
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