MINOR: tinfo: add the mask of enabled threads in each group

In order to replace the global "all_threads_mask" we'll need to have an
equivalent per group. Take this opportunity for calling it threads_enabled
and make sure which ones are counted there (in case in the future we allow
to stop some).

include/haproxy/tinfo-t.h

@@ -52,6 +52,7 @@ enum {
  * at 1 so tgroup[0] describes thread group 1.
  */
 struct tgroup_info {
+	ulong threads_enabled;     /* mask of threads enabled in this group */
 	uint base;                 /* first thread in this group */
 	uint count;                /* number of threads in this group */
 	ulong tgid_bit;            /* bit corresponding to the tgroup ID */

src/haproxy.c

@@ -2973,6 +2973,7 @@ static void *run_thread_poll_loop(void *data)
 		ptff->fct();
 
 #ifdef USE_THREAD
+	_HA_ATOMIC_AND(&ha_tgroup_info[ti->tgid].threads_enabled, ~ti->ltid_bit);
 	_HA_ATOMIC_AND(&all_threads_mask, ~tid_bit);
 	if (tid > 0)
 		pthread_exit(NULL);

src/thread.c

@@ -1082,6 +1082,11 @@ int thread_map_to_groups()
 		ha_thread_info[t].ltid_bit = 1UL << ha_thread_info[t].ltid;
 	}
 
+	for (g = 0; g < global.nbtgroups; g++) {
+		ha_tgroup_info[g].threads_enabled = nbits(ha_tgroup_info[g].count);
+
+	}
+
 	return 0;
 }