Revert "Fix different issues when requesting memory per cpu/node."

This reverts commit bf4cb0b.

Bug 5240, Bug 4895 and Bug 4976.

NEWS

@@ -26,8 +26,9 @@ documents those changes that are of interest to users and administrators.
     stage-out is completed.
  -- Reorder proctrack/task plugin load in the slurmstepd to match that of slurmd
     and avoid race condition calling task before proctrack can introduce.
-    qos as def_qos_id.
  -- Prevent reboot of a busy KNL node when requesting inactive features.
+ -- Revert to previous behavior when requesting memory per cpu/node introduced
+    in 17.11.7.
 
 * Changes in Slurm 17.11.7
 ==========================

src/plugins/sched/backfill/backfill.c

@@ -1401,10 +1401,6 @@ static int _attempt_backfill(void)
 				continue;
 		}
 		job_ptr->part_ptr = part_ptr;
-		if (job_limits_check(&job_ptr, true) != WAIT_NO_REASON) {
-			/* should never happen */
-			continue;
-		}
 
 		if (debug_flags & DEBUG_FLAG_BACKFILL) {
 			char job_id_str[64];

src/plugins/select/cons_res/job_test.c

@@ -3858,7 +3858,23 @@ extern int cr_job_test(struct job_record *job_ptr, bitstr_t *node_bitmap,
 		for (i = 0; i < job_res->nhosts; i++) {
 			job_res->memory_allocated[i] = save_mem;
 		}
+	} else {	/* --mem=0, allocate job all memory on node */
+		uint64_t avail_mem, lowest_mem = 0;
+		first = bit_ffs(job_res->node_bitmap);
+		if (first != -1)
+			last  = bit_fls(job_res->node_bitmap);
+		else
+			last = first - 1;
+		for (i = first, j = 0; i <= last; i++) {
+			if (!bit_test(job_res->node_bitmap, i))
+				continue;
+			avail_mem = select_node_record[i].real_memory -
+				    select_node_record[i].mem_spec_limit;
+			if ((j == 0) || (lowest_mem > avail_mem))
+				lowest_mem = avail_mem;
+			job_res->memory_allocated[j++] = avail_mem;
+		}
+		details_ptr->pn_min_memory = lowest_mem;
 	}
-
 	return error_code;
 }