job-manager: add 'final' flag to sched.free

Problem: a recent change proposed to RFC 27 says the final
sched.free should contain a boolean 'final' flag indicating
when the last resource fragment is being released.

Set the 'final' flag to the scheduler.

Author: garlick

src/modules/job-manager/alloc.c

@@ -98,16 +98,20 @@ static void interface_teardown (struct alloc *alloc, char *s, int errnum)
 
 /* Send sched.free request.
  */
-int free_request (struct alloc *alloc, flux_jobid_t id, json_t *R)
+int free_request (struct alloc *alloc,
+                  flux_jobid_t id,
+                  json_t *R,
+                  bool final)
 {
     flux_msg_t *msg;
 
     if (!(msg = flux_request_encode ("sched.free", NULL)))
         return -1;
     if (flux_msg_pack (msg,
-                       "{s:I s:O}",
+                       "{s:I s:O s:b}",
                        "id", id,
-                       "R", R) < 0)
+                       "R", R,
+                       "final", final) < 0)
         goto error;
     if (flux_send (alloc->ctx->h, msg, 0) < 0)
         goto error;
@@ -180,7 +184,7 @@ static void alloc_response_cb (flux_t *h,
         (void)json_object_del (R, "scheduling");
 
         if (!job) {
-            (void)free_request (alloc, id, R);
+            (void)free_request (alloc, id, R, true);
             break;
         }
         if (job_priority_queue_delete (alloc->sent, job) < 0)
@@ -486,10 +490,13 @@ static void check_cb (flux_reactor_t *r,
                                    NULL);
 }
 
-int alloc_send_free_request (struct alloc *alloc, json_t *R, flux_jobid_t id)
+int alloc_send_free_request (struct alloc *alloc,
+                             json_t *R,
+                             flux_jobid_t id,
+                             bool final)
 {
     if (alloc->scheduler_is_online) {
-        if (free_request (alloc, id, R) < 0)
+        if (free_request (alloc, id, R, final) < 0)
             return -1;
     }
     return 0;

src/modules/job-manager/alloc.h

@@ -50,7 +50,10 @@ int alloc_pending_count (struct alloc *alloc);
 
 /* Release resources back to the scheduler.
  */
-int alloc_send_free_request (struct alloc *alloc, json_t *R, flux_jobid_t id);
+int alloc_send_free_request (struct alloc *alloc,
+                             json_t *R,
+                             flux_jobid_t id,
+                             bool final);
 
 /* List pending jobs
  */

src/modules/job-manager/housekeeping.c

@@ -227,16 +227,19 @@ static void allocation_release (struct allocation *a)
     struct idset *ranks = NULL;
     struct rlist *rl = NULL;
     json_t *R = NULL;
+    bool final = false;
 
     if ((ranks = get_housekept_ranks (a)) && idset_count (ranks) == 0) {
         idset_destroy (ranks);
         return; // nothing to do
     }
+    if (idset_empty (a->pending))
+        final = true;
 
     if (!ranks
         || !(rl = rlist_copy_ranks (a->rl, ranks))
         || !(R = rlist_to_R (rl))
-        || alloc_send_free_request (ctx->alloc, R, a->id) < 0
+        || alloc_send_free_request (ctx->alloc, R, a->id, final) < 0
         || rlist_remove_ranks (a->rl, ranks) < 0) {
         char *s = idset_encode (ranks, IDSET_FLAG_RANGE);
         flux_log (ctx->h,
@@ -457,7 +460,7 @@ int housekeeping_start (struct housekeeping *hk,
     }
     return 0;
 skip:
-    return alloc_send_free_request (hk->ctx->alloc, R, id);
+    return alloc_send_free_request (hk->ctx->alloc, R, id, true);
 }
 
 static int housekeeping_hello_respond_one (struct housekeeping *hk,