NEX-17501 Enable parallel crash dump
Reviewed by: Sanjay Nadkarni <sanjay.nadkarni@nexenta.com>
Reviewed by: Yuri Pankov <yuri.pankov@nexenta.com>
re #13613 rb4516 Tunables needs volatile keyword

@@ -19,10 +19,11 @@
  * CDDL HEADER END
  */
 
 /*
  * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright 2018 Nexenta Systems, Inc.  All rights reserved.
  * Copyright (c) 2016 by Delphix. All rights reserved.
  */
 
 #include <sys/machsystm.h>
 #include <sys/archsystm.h>

@@ -116,14 +117,14 @@
  */
 void *romp;             /* veritas driver won't load without romp 4154976 */
 /*
  * Declare these as initialized data so we can patch them.
  */
-pgcnt_t physmem = 0;    /* memory size in pages, patch if you want less */
-pgcnt_t segkpsize =
+volatile pgcnt_t physmem = 0; /* memory size in pages, patch if you want less */
+volatile pgcnt_t segkpsize =
     btop(SEGKPDEFSIZE); /* size of segkp segment in pages */
-uint_t segmap_percent = 6; /* Size of segmap segment */
+volatile uint_t segmap_percent = 6; /* Size of segmap segment */
 
 int use_cache = 1;              /* cache not reliable (605 bugs) with MP */
 int vac_copyback = 1;
 char *cache_mode = NULL;
 int use_mix = 1;

@@ -628,11 +629,11 @@
         }
 
         /*
          * Force a serial dump, since there are no CPUs to help.
          */
-        dump_plat_mincpu = 0;
+        dump_ncpu_low = 0;
 
         /*
          * We've managed to get here without going through the
          * normal panic code path. Try and save some useful
          * information.