svn commit: r262765 - head/sys/amd64/amd64

[Ed Maste]

Author: emaste
Date: Wed Mar  5 01:34:10 2014
New Revision: 262765
URL: http://svnweb.freebsd.org/changeset/base/262765

Log:
  Disable amd64 TLB Context ID (pcid) by default for now
  
  There are a number of reports of userspace application crashes that
  are "solved" by setting vm.pmap.pcid_enabled=0, including Java and the
  x11/mate-terminal port (PR ports/184362).
  
  I originally planned to disable this only in stable/10 (in r262753), but
  it has been pointed out that additional crash reports on HEAD are not
  likely to provide new insight into the problem.  The feature can easily
  be enabled for testing.

Modified:
  head/sys/amd64/amd64/pmap.c

Modified: head/sys/amd64/amd64/pmap.c
==============================================================================
--- head/sys/amd64/amd64/pmap.c	Wed Mar  5 01:33:15 2014	(r262764)
+++ head/sys/amd64/amd64/pmap.c	Wed Mar  5 01:34:10 2014	(r262765)
@@ -367,7 +367,7 @@ static int pmap_flags = PMAP_PDE_SUPERPA
 
 static struct unrhdr pcid_unr;
 static struct mtx pcid_mtx;
-int pmap_pcid_enabled = 1;
+int pmap_pcid_enabled = 0;
 SYSCTL_INT(_vm_pmap, OID_AUTO, pcid_enabled, CTLFLAG_RDTUN, &pmap_pcid_enabled,
     0, "Is TLB Context ID enabled ?");
 int invpcid_works = 0;