On 05/04/2021 15:39, Leon Romanovsky wrote:
> On Mon, Apr 05, 2021 at 03:15:18PM +0300, Gal Pressman wrote:
>> On 05/04/2021 14:57, Leon Romanovsky wrote:
>>> On Mon, Apr 05, 2021 at 02:47:21PM +0300, Gal Pressman wrote:
>>>> The new attribute indicates that the kernel copies DMA pages on fork,
>>>> hence libibverbs' fork support through madvise and MADV_DONTFORK is not
>>>> needed.
>>>>
>>>> The introduced attribute is always reported as supported since the
>>>> kernel has the patch that added the copy-on-fork behavior. This allows
>>>> the userspace library to identify older vs newer kernel versions.
>>>> Extra care should be taken when backporting this patch as it relies on
>>>> the fact that the copy-on-fork patch is merged, hence no check for
>>>> support is added.
>>>
>>> Please be more specific, add SHA-1 of that patch and wrote the same
>>> comment near "err = nla_put_u8(msg, RDMA_NLDEV_SYS_ATTR_COPY_ON_FORK,
>>> 1);" line.
>>>
>>> Thanks
>>
>> Should I put the original commit here? There were quite a lot of bug fixes and
>> followups that are required.
>
> IMHO, the last commit SHA will be enough, the one that has working
> functionality from your POV.
OK, so that would be:
4eae4efa2c29 ("hugetlb: do early cow when page pinned on src mm")
Which I now realize for-next isn't rebased on top of it yet, so these patches
should be applied after rebasing to v5.12-rc5.
