OS-2366 ddi_periodic_add(9F) is entirely rubbish

@@ -2243,18 +2243,22 @@
 
         (void) add_avsoftintr((void *)&softlevel1_hdl, 1, softlevel1,
             "softlevel1", NULL, NULL); /* XXX to be moved later */
 
         /*
-         * Register these software interrupts for ddi timer.
+         * Register software interrupt handlers for ddi_periodic_add(9F).
          * Software interrupts up to the level 10 are supported.
          */
         for (i = DDI_IPL_1; i <= DDI_IPL_10; i++) {
-                char name[sizeof ("timer_softintr") + 2];
-                (void) sprintf(name, "timer_softintr%02d", i);
+                /*
+                 * The constant string "ddi_periodic", below, is only used to
+                 * print debugging information.  Generating a dynamic string
+                 * for each soft level is a waste of kernel memory.
+                 */
                 (void) add_avsoftintr((void *)&softlevel_hdl[i-1], i,
-                    (avfunc)timer_softintr, name, (caddr_t)(uintptr_t)i, NULL);
+                    (avfunc)ddi_periodic_softintr, "ddi_periodic",
+                    (caddr_t)(uintptr_t)i, NULL);
         }
 
 #if !defined(__xpv)
         if (modload("drv", "amd_iommu") < 0) {
                 PRM_POINT("No AMD IOMMU present\n");