Hi Julian!
On 2019-12-17T21:03:47-0800, Julian Brown <jul...@codesourcery.com> wrote:
> This part contains the libgomp runtime support for the GOMP_MAP_ATTACH and
> GOMP_MAP_DETACH mapping kinds
> --- a/libgomp/target.c
> +++ b/libgomp/target.c
> @@ -1203,6 +1211,32 @@ gomp_map_vars_internal (struct gomp_device_descr
> *devicep,
> + case GOMP_MAP_ATTACH:
> + {
> + cur_node.host_start = (uintptr_t) hostaddrs[i];
> + cur_node.host_end = cur_node.host_start + sizeof (void *);
> + splay_tree_key n = splay_tree_lookup (mem_map, &cur_node);
> + if (n != NULL)
> + {
> + tgt->list[i].key = n;
> + tgt->list[i].offset = cur_node.host_start - n->host_start;
> + tgt->list[i].length = n->host_end - n->host_start;
> + tgt->list[i].copy_from = false;
> + tgt->list[i].always_copy_from = false;
> + tgt->list[i].do_detach
> + = (pragma_kind != GOMP_MAP_VARS_OPENACC_ENTER_DATA);
> + n->refcount++;
> + }
> + else
> + {
> + gomp_mutex_unlock (&devicep->lock);
> + gomp_fatal ("outer struct not mapped for attach");
> + }
> + gomp_attach_pointer (devicep, aq, mem_map, n,
> + (uintptr_t) hostaddrs[i], sizes[i],
> + cbufp);
> + continue;
> + }
For the OpenACC runtime API 'acc_attach' etc. routines they don't, so
what's the conceptual reason that for the corresponding OpenACC directive
variants, 'GOMP_MAP_ATTACH' etc. here participate in reference counting
('n->refcount++' above)? I understand OpenACC 'attach'/'detach' clauses
to be simple "executable clauses", which just update some values
somewhere (say, like 'GOMP_MAP_ALWAYS_POINTER'), but they don't alter any
mapping state, thus wouldn't appear to need reference counting?
Grüße
Thomas
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