changeset 53907:a76b7884b59a

8208277: Code cache heap (-XX:ReservedCodeCacheSize) doesn't work with 1GB LargePages Summary: Use huge pages for code cache if ReservedCodeCacheSize == InitialCodeCacheSize Reviewed-by: kvn
author thartmann
date Thu, 06 Dec 2018 10:07:54 +0100
parents c5c0db0b7c2f
children c09bff7928e8
files src/hotspot/share/code/codeCache.cpp src/hotspot/share/code/codeCache.hpp src/hotspot/share/compiler/compilerDefinitions.cpp
diffstat 3 files changed, 14 insertions(+), 7 deletions(-) [+]
line wrap: on
line diff
--- a/src/hotspot/share/code/codeCache.cpp	Thu Dec 06 12:39:28 2018 +0530
+++ b/src/hotspot/share/code/codeCache.cpp	Thu Dec 06 10:07:54 2018 +0100
@@ -289,7 +289,7 @@
 
   // If large page support is enabled, align code heaps according to large
   // page size to make sure that code cache is covered by large pages.
-  const size_t alignment = MAX2(page_size(false), (size_t) os::vm_allocation_granularity());
+  const size_t alignment = MAX2(page_size(false, 8), (size_t) os::vm_allocation_granularity());
   non_nmethod_size = align_up(non_nmethod_size, alignment);
   profiled_size    = align_down(profiled_size, alignment);
 
@@ -314,10 +314,14 @@
   add_heap(non_profiled_space, "CodeHeap 'non-profiled nmethods'", CodeBlobType::MethodNonProfiled);
 }
 
-size_t CodeCache::page_size(bool aligned) {
+size_t CodeCache::page_size(bool aligned, size_t min_pages) {
   if (os::can_execute_large_page_memory()) {
-    return aligned ? os::page_size_for_region_aligned(ReservedCodeCacheSize, 8) :
-                     os::page_size_for_region_unaligned(ReservedCodeCacheSize, 8);
+    if (InitialCodeCacheSize < ReservedCodeCacheSize) {
+      // Make sure that the page size allows for an incremental commit of the reserved space
+      min_pages = MAX2(min_pages, (size_t)8);
+    }
+    return aligned ? os::page_size_for_region_aligned(ReservedCodeCacheSize, min_pages) :
+                     os::page_size_for_region_unaligned(ReservedCodeCacheSize, min_pages);
   } else {
     return os::vm_page_size();
   }
--- a/src/hotspot/share/code/codeCache.hpp	Thu Dec 06 12:39:28 2018 +0530
+++ b/src/hotspot/share/code/codeCache.hpp	Thu Dec 06 10:07:54 2018 +0100
@@ -111,7 +111,6 @@
   static CodeHeap* get_code_heap(int code_blob_type);         // Returns the CodeHeap for the given CodeBlobType
   // Returns the name of the VM option to set the size of the corresponding CodeHeap
   static const char* get_code_heap_flag_name(int code_blob_type);
-  static size_t page_size(bool aligned = true);               // Returns the page size used by the CodeCache
   static ReservedCodeSpace reserve_heap_memory(size_t size);  // Reserves one continuous chunk of memory for the CodeHeaps
 
   // Iteration
@@ -133,6 +132,7 @@
  public:
   // Initialization
   static void initialize();
+  static size_t page_size(bool aligned = true, size_t min_pages = 1); // Returns the page size used by the CodeCache
 
   static int code_heap_compare(CodeHeap* const &lhs, CodeHeap* const &rhs);
 
--- a/src/hotspot/share/compiler/compilerDefinitions.cpp	Thu Dec 06 12:39:28 2018 +0530
+++ b/src/hotspot/share/compiler/compilerDefinitions.cpp	Thu Dec 06 10:07:54 2018 +0100
@@ -23,6 +23,7 @@
  */
 
 #include "precompiled.hpp"
+#include "code/codeCache.hpp"
 #include "runtime/globals.hpp"
 #include "runtime/globals_extension.hpp"
 #include "compiler/compilerDefinitions.hpp"
@@ -200,8 +201,10 @@
     FLAG_SET_ERGO(uintx, ReservedCodeCacheSize,
                   MIN2(CODE_CACHE_DEFAULT_LIMIT, (size_t)ReservedCodeCacheSize * 5));
   }
-  // Enable SegmentedCodeCache if TieredCompilation is enabled and ReservedCodeCacheSize >= 240M
-  if (FLAG_IS_DEFAULT(SegmentedCodeCache) && ReservedCodeCacheSize >= 240*M) {
+  // Enable SegmentedCodeCache if TieredCompilation is enabled, ReservedCodeCacheSize >= 240M
+  // and the code cache contains at least 8 pages (segmentation disables advantage of huge pages).
+  if (FLAG_IS_DEFAULT(SegmentedCodeCache) && ReservedCodeCacheSize >= 240*M &&
+      8 * CodeCache::page_size() <= ReservedCodeCacheSize) {
     FLAG_SET_ERGO(bool, SegmentedCodeCache, true);
   }
   if (!UseInterpreter) { // -Xcomp