Re: [PATCH v2] mm/ksm: ignore STABLE_FLAG of rmap_item->address in rmap_walk_ksm

[Jia He <hejianet@gmail.com>]

Hi Suzuki

On 5/24/2018 4:44 PM, Suzuki K Poulose Wrote:
> On 14/05/18 10:45, Suzuki K Poulose wrote:
>> On 10/05/18 00:31, Andrew Morton wrote:
>>> On Fri,A  4 May 2018 11:11:46 +0800 Jia He <hejianet@gmail.com> wrote:
>>>
>>>> In our armv8a server(QDF2400), I noticed lots of WARN_ON caused by PAGE_SIZE
>>>> unaligned for rmap_item->address under memory pressure tests(start 20 guests
>>>> and run memhog in the host).
>>>>
>>>> ...
>>>>
>>>> In rmap_walk_ksm, the rmap_item->address might still have the STABLE_FLAG,
>>>> then the start and end in handle_hva_to_gpa might not be PAGE_SIZE aligned.
>>>> Thus it will cause exceptions in handle_hva_to_gpa on arm64.
>>>>
>>>> This patch fixes it by ignoring(not removing) the low bits of address when
>>>> doing rmap_walk_ksm.
>>>>
>>>> Signed-off-by: jia.he@hxt-semitech.com
>>>
>>> I assumed you wanted this patch to be committed as
>>> From:jia.he@hxt-semitech.com rather than From:hejianet@gmail.com, so I
>>> made that change.A  Please let me know if this was inappropriate.
>>>
>>> You can do this yourself by adding an explicit From: line to the very
>>> start of the patch's email text.
>>>
>>> Also, a storm of WARN_ONs is pretty poor behaviour.A  Is that the only
>>> misbehaviour which this bug causes?A  Do you think the fix should be
>>> backported into earlier kernels?
>>>
> 
> 
> Jia, Andrew,
> 
> What is the status of this patch ?
> 
> Suzuki
I thought the patch is merged into mmotm tree.
http://www.ozlabs.org/~akpm/mmotm/series
But I don't know what is the next step.

Cheers,
Jia