[ofiwg] Hugepages usage in libfabric

Jason Gunthorpe jgg at ziepe.ca
Wed Apr 10 10:05:05 PDT 2019

On Wed, Apr 10, 2019 at 05:01:57PM +0000, Hefty, Sean wrote:
> > > > If the app isn't forking it shouldn't even be calling ibv_fork_init in
> > > > the first place, which solves both problems.
> > >
> > > Libfabric calls this because it has no idea if the higher level user
> > > will call fork or not.  The default is to assume this for
> > > correctness.
> > 
> > You think the rest of libfabric is fork safe?
> There's no guarantee that library objects will be usable across fork.

I mean that if the app calls fork() the existing process or the child
won't completely explode ie because:

1) Missing MADV_DONTFORK mean that the parent process memory is
   corrupted upon fork
2) Use of hidden threads means that the child deadlocks immediately
   do the inherent problems with fork and threads

Not that libfabric objects will be useful in the child.


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