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

From: Nicolas Morey Chaisemartin
Date: Wed May 11 2016 - 07:52:50 EST




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.

Nicolas