[ofiwg] fork support and MR cache

[Jason Gunthorpe]

On Thu, Oct 08, 2020 at 05:17:51AM +0000, Hefty, Sean wrote:

> There have been extensive discussions on github around the MR cache,
> deadlocks, libibverbs madvise tracking, and fork.  The current
> direction is to only enable the MR cache when fork is disabled.
> This was done to work-around internal libibverbs tracking.  But I
> suspect that bypassing that tracking (which is possible) can still
> lead to issues when registrations are made through the MR cache.

MADV_DONTFORK will be obsolete starting in kernel v5.9

If you can test and confirm that everything works without it then we
can detect and disable ibv_fork_init on new kernels.

Jason