On Mon, Nov 30, 2015 at 21:49:02 +0100, Jakub Jelinek wrote:
> On Mon, Nov 30, 2015 at 11:29:34PM +0300, Ilya Verbin wrote:
> > You're right, it doesn't deallocate memory on the device if DSO leaves
> > nonzero
> > refcount. And currently host compiler doesn't set MSB in host_var_table,
> > it's
> > set only by accel compiler. But it's possible to do splay_tree_lookup for
> > each
> > var to determine whether is it linked or not, like in the patch bellow.
> > Or do you prefer to set the bit in host compiler too? It requires
> > lookup_attribute ("omp declare target link") for all vars in the table
> > during
> > compilation, but allows to do splay_tree_lookup at run-time only for vars
> > with
> > MSB set in host_var_table.
> > Unfortunately, calling gomp_exit_data from gomp_unload_image_from_device
> > works
> > only for DSO, but it crashed when an executable leaves nonzero refcount,
> > because
> > target device may be already uninitialized from plugin's __run_exit_handlers
> > (and it is in case of intelmic), so gomp_exit_data cannot run free_func.
> > Is it possible do add some atexit (...) to libgomp, which will set
> > shutting_down
> > flag, and just do nothing in gomp_unload_image_from_device if it is set?
>
> Sorry, I didn't mean you should call gomp_exit_data, what I meant was that
> you perform the same action as would delete(var) do in that case.
> Calling gomp_exit_data e.g. looks it up again etc.
> Supposedly having the MSB in host table too is useful, so if you could
> handle that, it would be nice. And splay_tree_lookup only if the MSB is
> set.
> So,
> if (!host_data_has_msb_set)
> splay_tree_remove (&devicep->mem_map, &k);
> else
> {
> splay_tree_key n = splay_tree_lookup (&devicep->mem_map, &k);
> if (n->link_key)
> {
> n->refcount = 0;
> n->link_key = NULL;
> splay_tree_remove (&devicep->mem_map, n);
> if (n->tgt->refcount > 1)
> n->tgt->refcount--;
> else
> gomp_unmap_tgt (n->tgt);
> }
> else
> splay_tree_remove (&devicep->mem_map, n);
> }
> or so.
Ok, but it doesn't solve the issue with doing it for the executable, because
gomp_unmap_tgt (n->tgt) will want to run free_func on uninitialized device.
-- Ilya
