svn commit: r343668 - head/sys/i386/i386

[Konstantin Belousov]

Author: kib
Date: Fri Feb  1 21:09:36 2019
New Revision: 343668
URL: https://svnweb.freebsd.org/changeset/base/343668

Log:
  Disable boot-time memory test on i386 be default.
  
  With the current 24G memory limit for GENERIC, the boot time test
  causes quite visible delay, amplified by the default
  debug.late_console = 0.
  
  The comment text is copied from the same setting explanation for
  amd64.
  
  Suggested by:	bde
  Discussed with:	emaste
  Sponsored by:	The FreeBSD Foundation
  MFC after:	2 months

Modified:
  head/sys/i386/i386/machdep.c

Modified: head/sys/i386/i386/machdep.c
==============================================================================
--- head/sys/i386/i386/machdep.c	Fri Feb  1 20:46:47 2019	(r343667)
+++ head/sys/i386/i386/machdep.c	Fri Feb  1 21:09:36 2019	(r343668)
@@ -2005,13 +2005,15 @@ physmap_done:
 		Maxmem = atop(physmap[physmap_idx + 1]);
 
 	/*
-	 * By default enable the memory test on real hardware, and disable
-	 * it if we appear to be running in a VM.  This avoids touching all
-	 * pages unnecessarily, which doesn't matter on real hardware but is
-	 * bad for shared VM hosts.  Use a general name so that
-	 * one could eventually do more with the code than just disable it.
+	 * The boot memory test is disabled by default, as it takes a
+	 * significant amount of time on large-memory systems, and is
+	 * unfriendly to virtual machines as it unnecessarily touches all
+	 * pages.
+	 *
+	 * A general name is used as the code may be extended to support
+	 * additional tests beyond the current "page present" test.
 	 */
-	memtest = (vm_guest > VM_GUEST_NO) ? 0 : 1;
+	memtest = 0;
 	TUNABLE_ULONG_FETCH("hw.memtest.tests", &memtest);
 
 	if (atop(physmap[physmap_idx + 1]) != Maxmem &&