Re: [Question] Missing data after DMA read transfer - mm issue with transparent huge page?

[Nicolas Morey-Chaisemartin]

Le 05/11/2016 à 04:51 PM, Jerome Glisse a écrit :
> On Wed, May 11, 2016 at 01:15:54PM +0200, Nicolas Morey Chaisemartin wrote:
>>
>> Le 05/10/2016 à 12:01 PM, Jerome Glisse a écrit :
>>> On Tue, May 10, 2016 at 09:04:36AM +0200, Nicolas Morey Chaisemartin wrote:
>>>> Le 05/03/2016 à 12:11 PM, Jerome Glisse a écrit :
>>>>> On Mon, May 02, 2016 at 09:04:02PM -0700, Hugh Dickins wrote:
>>>>>> On Fri, 29 Apr 2016, Nicolas Morey Chaisemartin wrote:
>> [...]
>>>> Hi,
>>>>
>>>> I backported the patch to 3.10 (had to copy paste pmd_protnone defitinition from 4.5) and it's working !
>>>> I'll open a ticket in Redhat tracker to try and get this fixed in RHEL7.
>>>>
>>>> I have a dumb question though: how can we end up in numa/misplaced memory code on a single socket system?
>>>>
>>> This patch is not a fix, do you see bug message in kernel log ? Because if
>>> you do that it means we have a bigger issue.
>>>
>>> You did not answer one of my previous question, do you set get_user_pages
>>> with write = 1 as a paremeter ?
>>>
>>> Also it would be a lot easier if you were testing with lastest 4.6 or 4.5
>>> not RHEL kernel as they are far appart and what might looks like same issue
>>> on both might be totaly different bugs.
>>>
>>> If you only really care about RHEL kernel then open a bug with Red Hat and
>>> you can add me in bug-cc <jglisse@xxxxxxxxxx>
>>>
>>> Cheers,
>>> Jérôme
>> I finally managed to get a proper setup.
>> I build a vanilla 4.5 kernel from git tree using the Centos7 config, my test fails as usual.
>> I applied your patch, rebuild => still fails and no new messages in dmesg.
>>
>> Now that I don't have to go through the RPM repackaging, I can try out things much quicker if you have any ideas.
>>
> Still an issue if you boot with transparent_hugepage=never ?
>
> Also to simplify investigation force write to 1 all the time no matter what.
>
> Cheers,
> Jérôme

With transparent_hugepage=never I can't see the bug anymore.

Nicolas