diff src/os/linux/vm/os_linux.cpp @ 12840:aa6f2ea19d8f

Merge
author jcoomes
date Fri, 11 Oct 2013 08:27:21 -0700
parents 899ecf76b570 263f2c796d6c
children e4f478e7781b
line wrap: on
line diff
--- a/src/os/linux/vm/os_linux.cpp	Thu Oct 10 13:25:51 2013 -0700
+++ b/src/os/linux/vm/os_linux.cpp	Fri Oct 11 08:27:21 2013 -0700
@@ -3361,13 +3361,15 @@
   if (FLAG_IS_DEFAULT(UseHugeTLBFS) &&
       FLAG_IS_DEFAULT(UseSHM) &&
       FLAG_IS_DEFAULT(UseTransparentHugePages)) {
-    // If UseLargePages is specified on the command line try all methods,
-    // if it's default, then try only UseTransparentHugePages.
-    if (FLAG_IS_DEFAULT(UseLargePages)) {
-      UseTransparentHugePages = true;
-    } else {
-      UseHugeTLBFS = UseTransparentHugePages = UseSHM = true;
-    }
+
+    // The type of large pages has not been specified by the user.
+
+    // Try UseHugeTLBFS and then UseSHM.
+    UseHugeTLBFS = UseSHM = true;
+
+    // Don't try UseTransparentHugePages since there are known
+    // performance issues with it turned on. This might change in the future.
+    UseTransparentHugePages = false;
   }
 
   if (UseTransparentHugePages) {
@@ -3393,9 +3395,19 @@
 }
 
 void os::large_page_init() {
-  if (!UseLargePages) {
+  if (!UseLargePages &&
+      !UseTransparentHugePages &&
+      !UseHugeTLBFS &&
+      !UseSHM) {
+    // Not using large pages.
+    return;
+  }
+
+  if (!FLAG_IS_DEFAULT(UseLargePages) && !UseLargePages) {
+    // The user explicitly turned off large pages.
+    // Ignore the rest of the large pages flags.
+    UseTransparentHugePages = false;
     UseHugeTLBFS = false;
-    UseTransparentHugePages = false;
     UseSHM = false;
     return;
   }