Date: Sun, 22 Jan 2012 21:25:47 +0000 (UTC) From: Gavin Atkinson <gavin@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-8@freebsd.org Subject: svn commit: r230472 - in stable/8/sys: amd64/amd64 i386/i386 Message-ID: <201201222125.q0MLPlDg093459@svn.freebsd.org>
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Author: gavin Date: Sun Jan 22 21:25:47 2012 New Revision: 230472 URL: http://svn.freebsd.org/changeset/base/230472 Log: Merge r229085 from head: Default to not performing the early-boot memory tests when we detect we are booting inside a VM. There are three reasons to disable this: o It causes the VM host to believe that all the tested pages or RAM are in use. This in turn may force the host to page out pages of RAM belonging to other VMs, or otherwise cause problems with fair resource sharing on the VM cluster. o It adds significant time to the boot process (around 1 second/Gig in testing) o It is unnecessary - the host should have already verified that the memory is functional etc. Note that this simply changes the default when in a VM - it can still be overridden using the hw.memtest.tests tunable. Early MFC requested by: bz Modified: stable/8/sys/amd64/amd64/machdep.c stable/8/sys/i386/i386/machdep.c Directory Properties: stable/8/sys/ (props changed) stable/8/sys/amd64/include/xen/ (props changed) stable/8/sys/cddl/contrib/opensolaris/ (props changed) stable/8/sys/contrib/dev/acpica/ (props changed) stable/8/sys/contrib/pf/ (props changed) Modified: stable/8/sys/amd64/amd64/machdep.c ============================================================================== --- stable/8/sys/amd64/amd64/machdep.c Sun Jan 22 20:26:46 2012 (r230471) +++ stable/8/sys/amd64/amd64/machdep.c Sun Jan 22 21:25:47 2012 (r230472) @@ -1351,10 +1351,13 @@ getmemsize(caddr_t kmdp, u_int64_t first Maxmem = atop(physmem_tunable); /* - * By default keep the memtest enabled. Use a general name so that + * 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. */ - memtest = 1; + memtest = (vm_guest > VM_GUEST_NO) ? 0 : 1; TUNABLE_ULONG_FETCH("hw.memtest.tests", &memtest); /* Modified: stable/8/sys/i386/i386/machdep.c ============================================================================== --- stable/8/sys/i386/i386/machdep.c Sun Jan 22 20:26:46 2012 (r230471) +++ stable/8/sys/i386/i386/machdep.c Sun Jan 22 21:25:47 2012 (r230472) @@ -2302,10 +2302,13 @@ physmap_done: Maxmem = atop(physmap[physmap_idx + 1]); /* - * By default keep the memtest enabled. Use a general name so that + * 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. */ - memtest = 1; + memtest = (vm_guest > VM_GUEST_NO) ? 0 : 1; TUNABLE_ULONG_FETCH("hw.memtest.tests", &memtest); if (atop(physmap[physmap_idx + 1]) != Maxmem &&
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