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

[Anisse Astier <anisse@astier.eu>]

On Tue, May 19, 2015 at 3:58 AM, yalin wang <yalin.wang2010@gmail.com> wrote:
> 2015-05-18 21:04 GMT+08:00 Anisse Astier <anisse@astier.eu>:
>> On Mon, May 18, 2015 at 3:02 PM, Pavel Machek <pavel@ucw.cz> 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.
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>> Please read the FAQ at  http://www.tux.org/lkml/
> 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

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>