8006952: Slow VM due to excessive code cache freelist iteration

Remove continous free block requirement

Reviewed-by: kvn

hotspot/src/share/vm/code/codeBlob.cpp

@@ -348,14 +348,14 @@ RuntimeStub* RuntimeStub::new_runtime_stub(const char* stub_name,
 
 
 void* RuntimeStub::operator new(size_t s, unsigned size) {
-  void* p = CodeCache::allocate(size);
+  void* p = CodeCache::allocate(size, true);
   if (!p) fatal("Initial size of CodeCache is too small");
   return p;
 }
 
 // operator new shared by all singletons:
 void* SingletonBlob::operator new(size_t s, unsigned size) {
-  void* p = CodeCache::allocate(size);
+  void* p = CodeCache::allocate(size, true);
   if (!p) fatal("Initial size of CodeCache is too small");
   return p;
 }

hotspot/src/share/vm/code/codeCache.cpp

@@ -172,7 +172,7 @@ nmethod* CodeCache::next_nmethod (CodeBlob* cb) {
 
 static size_t maxCodeCacheUsed = 0;
 
-CodeBlob* CodeCache::allocate(int size) {
+CodeBlob* CodeCache::allocate(int size, bool is_critical) {
   // Do not seize the CodeCache lock here--if the caller has not
   // already done so, we are going to lose bigtime, since the code
   // cache will contain a garbage CodeBlob until the caller can
@@ -183,7 +183,7 @@ CodeBlob* CodeCache::allocate(int size) {
   CodeBlob* cb = NULL;
   _number_of_blobs++;
   while (true) {
-    cb = (CodeBlob*)_heap->allocate(size);
+    cb = (CodeBlob*)_heap->allocate(size, is_critical);
     if (cb != NULL) break;
     if (!_heap->expand_by(CodeCacheExpansionSize)) {
       // Expansion failed
@@ -192,8 +192,8 @@ CodeBlob* CodeCache::allocate(int size) {
     if (PrintCodeCacheExtension) {
       ResourceMark rm;
       tty->print_cr("code cache extended to [" INTPTR_FORMAT ", " INTPTR_FORMAT "] (%d bytes)",
-                    (intptr_t)_heap->begin(), (intptr_t)_heap->end(),
+                    (intptr_t)_heap->low_boundary(), (intptr_t)_heap->high(),
-                    (address)_heap->end() - (address)_heap->begin());
+                    (address)_heap->high() - (address)_heap->low_boundary());
     }
   }
   maxCodeCacheUsed = MAX2(maxCodeCacheUsed, ((address)_heap->high_boundary() -
@@ -608,13 +608,13 @@ void CodeCache::verify_oops() {
 
 address CodeCache::first_address() {
   assert_locked_or_safepoint(CodeCache_lock);
-  return (address)_heap->begin();
+  return (address)_heap->low_boundary();
 }
 
 
 address CodeCache::last_address() {
   assert_locked_or_safepoint(CodeCache_lock);
-  return (address)_heap->end();
+  return (address)_heap->high();
 }
 
 
@@ -996,10 +996,9 @@ void CodeCache::print() {
 void CodeCache::print_summary(outputStream* st, bool detailed) {
   size_t total = (_heap->high_boundary() - _heap->low_boundary());
   st->print_cr("CodeCache: size=" SIZE_FORMAT "Kb used=" SIZE_FORMAT
-               "Kb max_used=" SIZE_FORMAT "Kb free=" SIZE_FORMAT
+               "Kb max_used=" SIZE_FORMAT "Kb free=" SIZE_FORMAT "Kb",
-               "Kb max_free_chunk=" SIZE_FORMAT "Kb",
                total/K, (total - unallocated_capacity())/K,
-               maxCodeCacheUsed/K, unallocated_capacity()/K, largest_free_block()/K);
+               maxCodeCacheUsed/K, unallocated_capacity()/K);
 
   if (detailed) {
     st->print_cr(" bounds [" INTPTR_FORMAT ", " INTPTR_FORMAT ", " INTPTR_FORMAT "]",
@@ -1018,19 +1017,8 @@ void CodeCache::print_summary(outputStream* st, bool detailed) {
 
 void CodeCache::log_state(outputStream* st) {
   st->print(" total_blobs='" UINT32_FORMAT "' nmethods='" UINT32_FORMAT "'"
-            " adapters='" UINT32_FORMAT "' free_code_cache='" SIZE_FORMAT "'"
+            " adapters='" UINT32_FORMAT "' free_code_cache='" SIZE_FORMAT "'",
-            " largest_free_block='" SIZE_FORMAT "'",
             nof_blobs(), nof_nmethods(), nof_adapters(),
-            unallocated_capacity(), largest_free_block());
+            unallocated_capacity());
 }
 
-size_t CodeCache::largest_free_block() {
-  // This is called both with and without CodeCache_lock held so
-  // handle both cases.
-  if (CodeCache_lock->owned_by_self()) {
-    return _heap->largest_free_block();
-  } else {
-    MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
-    return _heap->largest_free_block();
-  }
-}

hotspot/src/share/vm/code/codeCache.hpp

@@ -70,7 +70,7 @@ class CodeCache : AllStatic {
   static void initialize();
 
   // Allocation/administration
-  static CodeBlob* allocate(int size);              // allocates a new CodeBlob
+  static CodeBlob* allocate(int size, bool is_critical = false); // allocates a new CodeBlob
   static void commit(CodeBlob* cb);                 // called when the allocated CodeBlob has been filled
   static int alignment_unit();                      // guaranteed alignment of all CodeBlobs
   static int alignment_offset();                    // guaranteed offset of first CodeBlob byte within alignment unit (i.e., allocation header)
@@ -156,19 +156,13 @@ class CodeCache : AllStatic {
   static address  low_bound()                    { return (address) _heap->low_boundary(); }
   static address  high_bound()                   { return (address) _heap->high_boundary(); }
 
-  static bool has_space(int size) {
-    // Always leave some room in the CodeCache for I2C/C2I adapters
-    return largest_free_block() > (CodeCacheMinimumFreeSpace + size);
-  }
-
   // Profiling
   static address first_address();                // first address used for CodeBlobs
   static address last_address();                 // last  address used for CodeBlobs
   static size_t  capacity()                      { return _heap->capacity(); }
   static size_t  max_capacity()                  { return _heap->max_capacity(); }
   static size_t  unallocated_capacity()          { return _heap->unallocated_capacity(); }
-  static size_t  largest_free_block();
+  static bool    needs_flushing()                { return unallocated_capacity() < CodeCacheFlushingMinimumFreeSpace; }
-  static bool    needs_flushing()                { return largest_free_block() < CodeCacheFlushingMinimumFreeSpace; }
 
   static bool needs_cache_clean()                { return _needs_cache_clean; }
   static void set_needs_cache_clean(bool v)      { _needs_cache_clean = v;    }

hotspot/src/share/vm/code/nmethod.cpp

@@ -501,7 +501,6 @@ nmethod* nmethod::new_native_nmethod(methodHandle method,
   {
     MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
     int native_nmethod_size = allocation_size(code_buffer, sizeof(nmethod));
-    if (CodeCache::has_space(native_nmethod_size)) {
     CodeOffsets offsets;
     offsets.set_value(CodeOffsets::Verified_Entry, vep_offset);
     offsets.set_value(CodeOffsets::Frame_Complete, frame_complete);
@@ -511,7 +510,7 @@ nmethod* nmethod::new_native_nmethod(methodHandle method,
                                             basic_lock_owner_sp_offset,
                                             basic_lock_sp_offset, oop_maps);
     NOT_PRODUCT(if (nm != NULL)  nmethod_stats.note_native_nmethod(nm));
-      if (PrintAssembly && nm != NULL)
+    if (PrintAssembly && nm != NULL) {
       Disassembler::decode(nm);
     }
   }
@@ -538,7 +537,6 @@ nmethod* nmethod::new_dtrace_nmethod(methodHandle method,
   {
     MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
     int nmethod_size = allocation_size(code_buffer, sizeof(nmethod));
-    if (CodeCache::has_space(nmethod_size)) {
     CodeOffsets offsets;
     offsets.set_value(CodeOffsets::Verified_Entry, vep_offset);
     offsets.set_value(CodeOffsets::Dtrace_trap, trap_offset);
@@ -548,7 +546,7 @@ nmethod* nmethod::new_dtrace_nmethod(methodHandle method,
                                     &offsets, code_buffer, frame_size);
 
     NOT_PRODUCT(if (nm != NULL)  nmethod_stats.note_nmethod(nm));
-      if (PrintAssembly && nm != NULL)
+    if (PrintAssembly && nm != NULL) {
       Disassembler::decode(nm);
     }
   }
@@ -591,7 +589,7 @@ nmethod* nmethod::new_nmethod(methodHandle method,
       + round_to(handler_table->size_in_bytes(), oopSize)
       + round_to(nul_chk_table->size_in_bytes(), oopSize)
       + round_to(debug_info->data_size()       , oopSize);
-    if (CodeCache::has_space(nmethod_size)) {
+
     nm = new (nmethod_size)
     nmethod(method(), nmethod_size, compile_id, entry_bci, offsets,
             orig_pc_offset, debug_info, dependencies, code_buffer, frame_size,
@@ -600,7 +598,7 @@ nmethod* nmethod::new_nmethod(methodHandle method,
             nul_chk_table,
             compiler,
             comp_level);
-    }
+
     if (nm != NULL) {
       // To make dependency checking during class loading fast, record
       // the nmethod dependencies in the classes it is dependent on.
@@ -612,16 +610,19 @@ nmethod* nmethod::new_nmethod(methodHandle method,
       // classes the slow way is too slow.
       for (Dependencies::DepStream deps(nm); deps.next(); ) {
         Klass* klass = deps.context_type();
-        if (klass == NULL)  continue;  // ignore things like evol_method
+        if (klass == NULL) {
+          continue;  // ignore things like evol_method
+        }
 
         // record this nmethod as dependent on this klass
         InstanceKlass::cast(klass)->add_dependent_nmethod(nm);
       }
     }
     NOT_PRODUCT(if (nm != NULL)  nmethod_stats.note_nmethod(nm));
-    if (PrintAssembly && nm != NULL)
+    if (PrintAssembly && nm != NULL) {
       Disassembler::decode(nm);
     }
+  }
 
   // verify nmethod
   debug_only(if (nm) nm->verify();) // might block
@@ -798,13 +799,11 @@ nmethod::nmethod(
 }
 #endif // def HAVE_DTRACE_H
 
-void* nmethod::operator new(size_t size, int nmethod_size) {
+void* nmethod::operator new(size_t size, int nmethod_size) throw () {
-  void*  alloc = CodeCache::allocate(nmethod_size);
+  // Not critical, may return null if there is too little continuous memory
-  guarantee(alloc != NULL, "CodeCache should have enough space");
+  return CodeCache::allocate(nmethod_size);
-  return alloc;
 }
 
-
 nmethod::nmethod(
   Method* method,
   int nmethod_size,

hotspot/src/share/vm/compiler/compileBroker.cpp

@@ -1581,7 +1581,7 @@ void CompileBroker::compiler_thread_loop() {
       // We need this HandleMark to avoid leaking VM handles.
       HandleMark hm(thread);
 
-      if (CodeCache::largest_free_block() < CodeCacheMinimumFreeSpace) {
+      if (CodeCache::unallocated_capacity() < CodeCacheMinimumFreeSpace) {
         // the code cache is really full
         handle_full_code_cache();
       } else if (UseCodeCacheFlushing && CodeCache::needs_flushing()) {

hotspot/src/share/vm/memory/heap.cpp

@@ -42,7 +42,7 @@ CodeHeap::CodeHeap() {
   _log2_segment_size            = 0;
   _next_segment                 = 0;
   _freelist                     = NULL;
-  _free_segments                = 0;
+  _freelist_segments            = 0;
 }
 
 
@@ -115,8 +115,8 @@ bool CodeHeap::reserve(size_t reserved_size, size_t committed_size,
   }
 
   on_code_mapping(_memory.low(), _memory.committed_size());
-  _number_of_committed_segments = number_of_segments(_memory.committed_size());
+  _number_of_committed_segments = size_to_segments(_memory.committed_size());
-  _number_of_reserved_segments  = number_of_segments(_memory.reserved_size());
+  _number_of_reserved_segments  = size_to_segments(_memory.reserved_size());
   assert(_number_of_reserved_segments >= _number_of_committed_segments, "just checking");
 
   // reserve space for _segmap
@@ -149,8 +149,8 @@ bool CodeHeap::expand_by(size_t size) {
     if (!_memory.expand_by(dm)) return false;
     on_code_mapping(base, dm);
     size_t i = _number_of_committed_segments;
-    _number_of_committed_segments = number_of_segments(_memory.committed_size());
+    _number_of_committed_segments = size_to_segments(_memory.committed_size());
-    assert(_number_of_reserved_segments == number_of_segments(_memory.reserved_size()), "number of reserved segments should not change");
+    assert(_number_of_reserved_segments == size_to_segments(_memory.reserved_size()), "number of reserved segments should not change");
     assert(_number_of_reserved_segments >= _number_of_committed_segments, "just checking");
     // expand _segmap space
     size_t ds = align_to_page_size(_number_of_committed_segments) - _segmap.committed_size();
@@ -176,33 +176,44 @@ void CodeHeap::clear() {
 }
 
 
-void* CodeHeap::allocate(size_t size) {
+void* CodeHeap::allocate(size_t instance_size, bool is_critical) {
-  size_t length = number_of_segments(size + sizeof(HeapBlock));
+  size_t number_of_segments = size_to_segments(instance_size + sizeof(HeapBlock));
-  assert(length *_segment_size >= sizeof(FreeBlock), "not enough room for FreeList");
+  assert(segments_to_size(number_of_segments) >= sizeof(FreeBlock), "not enough room for FreeList");
 
   // First check if we can satify request from freelist
   debug_only(verify());
-  HeapBlock* block = search_freelist(length);
+  HeapBlock* block = search_freelist(number_of_segments, is_critical);
   debug_only(if (VerifyCodeCacheOften) verify());
   if (block != NULL) {
-    assert(block->length() >= length && block->length() < length + CodeCacheMinBlockLength, "sanity check");
+    assert(block->length() >= number_of_segments && block->length() < number_of_segments + CodeCacheMinBlockLength, "sanity check");
     assert(!block->free(), "must be marked free");
 #ifdef ASSERT
-    memset((void *)block->allocated_space(), badCodeHeapNewVal, size);
+    memset((void *)block->allocated_space(), badCodeHeapNewVal, instance_size);
 #endif
     return block->allocated_space();
   }
 
-  if (length < CodeCacheMinBlockLength) {
+  // Ensure minimum size for allocation to the heap.
-    length = CodeCacheMinBlockLength;
+  if (number_of_segments < CodeCacheMinBlockLength) {
+    number_of_segments = CodeCacheMinBlockLength;
   }
-  if (_next_segment + length <= _number_of_committed_segments) {
+
-    mark_segmap_as_used(_next_segment, _next_segment + length);
+  if (!is_critical) {
+    // Make sure the allocation fits in the unallocated heap without using
+    // the CodeCacheMimimumFreeSpace that is reserved for critical allocations.
+    if (segments_to_size(number_of_segments) > (heap_unallocated_capacity() - CodeCacheMinimumFreeSpace)) {
+      // Fail allocation
+      return NULL;
+    }
+  }
+
+  if (_next_segment + number_of_segments <= _number_of_committed_segments) {
+    mark_segmap_as_used(_next_segment, _next_segment + number_of_segments);
     HeapBlock* b =  block_at(_next_segment);
-    b->initialize(length);
+    b->initialize(number_of_segments);
-    _next_segment += length;
+    _next_segment += number_of_segments;
 #ifdef ASSERT
-    memset((void *)b->allocated_space(), badCodeHeapNewVal, size);
+    memset((void *)b->allocated_space(), badCodeHeapNewVal, instance_size);
 #endif
     return b->allocated_space();
   } else {
@@ -219,7 +230,7 @@ void CodeHeap::deallocate(void* p) {
 #ifdef ASSERT
   memset((void *)b->allocated_space(),
          badCodeHeapFreeVal,
-         size(b->length()) - sizeof(HeapBlock));
+         segments_to_size(b->length()) - sizeof(HeapBlock));
 #endif
   add_to_freelist(b);
 
@@ -299,32 +310,14 @@ size_t CodeHeap::max_capacity() const {
 }
 
 size_t CodeHeap::allocated_capacity() const {
-  // Start with the committed size in _memory;
+  // size of used heap - size on freelist
-  size_t l = _memory.committed_size();
+  return segments_to_size(_next_segment - _freelist_segments);
-
-  // Subtract the committed, but unused, segments
-  l -= size(_number_of_committed_segments - _next_segment);
-
-  // Subtract the size of the freelist
-  l -= size(_free_segments);
-
-  return l;
 }
 
-size_t CodeHeap::largest_free_block() const {
+// Returns size of the unallocated heap block
-  // First check unused space excluding free blocks.
+size_t CodeHeap::heap_unallocated_capacity() const {
-  size_t free_sz = size(_free_segments);
+  // Total number of segments - number currently used
-  size_t unused  = max_capacity() - allocated_capacity() - free_sz;
+  return segments_to_size(_number_of_reserved_segments - _next_segment);
-  if (unused >= free_sz)
-    return unused;
-
-  // Now check largest free block.
-  size_t len = 0;
-  for (FreeBlock* b = _freelist; b != NULL; b = b->link()) {
-    if (b->length() > len)
-      len = b->length();
-  }
-  return MAX2(unused, size(len));
 }
 
 // Free list management
@@ -365,7 +358,7 @@ void CodeHeap::add_to_freelist(HeapBlock *a) {
   assert(b != _freelist, "cannot be removed twice");
 
   // Mark as free and update free space count
-  _free_segments += b->length();
+  _freelist_segments += b->length();
   b->set_free();
 
   // First element in list?
@@ -400,7 +393,7 @@ void CodeHeap::add_to_freelist(HeapBlock *a) {
 
 // Search freelist for an entry on the list with the best fit
 // Return NULL if no one was found
-FreeBlock* CodeHeap::search_freelist(size_t length) {
+FreeBlock* CodeHeap::search_freelist(size_t length, bool is_critical) {
   FreeBlock *best_block = NULL;
   FreeBlock *best_prev  = NULL;
   size_t best_length = 0;
@@ -411,6 +404,16 @@ FreeBlock* CodeHeap::search_freelist(size_t length) {
   while(cur != NULL) {
     size_t l = cur->length();
     if (l >= length && (best_block == NULL || best_length > l)) {
+
+      // Non critical allocations are not allowed to use the last part of the code heap.
+      if (!is_critical) {
+        // Make sure the end of the allocation doesn't cross into the last part of the code heap
+        if (((size_t)cur + length) > ((size_t)high_boundary() - CodeCacheMinimumFreeSpace)) {
+          // the freelist is sorted by address - if one fails, all consecutive will also fail.
+          break;
+        }
+      }
+
       // Remember best block, its previous element, and its length
       best_block = cur;
       best_prev  = prev;
@@ -452,7 +455,7 @@ FreeBlock* CodeHeap::search_freelist(size_t length) {
   }
 
   best_block->set_used();
-  _free_segments -= length;
+  _freelist_segments -= length;
   return best_block;
 }
 
@@ -478,7 +481,7 @@ void CodeHeap::verify() {
   }
 
   // Verify that freelist contains the right amount of free space
-  //  guarantee(len == _free_segments, "wrong freelist");
+  //  guarantee(len == _freelist_segments, "wrong freelist");
 
   // Verify that the number of free blocks is not out of hand.
   static int free_block_threshold = 10000;

hotspot/src/share/vm/memory/heap.hpp

@@ -91,11 +91,11 @@ class CodeHeap : public CHeapObj<mtCode> {
   size_t       _next_segment;
 
   FreeBlock*   _freelist;
-  size_t       _free_segments;                   // No. of segments in freelist
+  size_t       _freelist_segments;               // No. of segments in freelist
 
   // Helper functions
-  size_t   number_of_segments(size_t size) const { return (size + _segment_size - 1) >> _log2_segment_size; }
+  size_t   size_to_segments(size_t size) const { return (size + _segment_size - 1) >> _log2_segment_size; }
-  size_t   size(size_t number_of_segments) const { return number_of_segments << _log2_segment_size; }
+  size_t   segments_to_size(size_t number_of_segments) const { return number_of_segments << _log2_segment_size; }
 
   size_t   segment_for(void* p) const            { return ((char*)p - _memory.low()) >> _log2_segment_size; }
   HeapBlock* block_at(size_t i) const            { return (HeapBlock*)(_memory.low() + (i << _log2_segment_size)); }
@@ -110,7 +110,7 @@ class CodeHeap : public CHeapObj<mtCode> {
 
   // Toplevel freelist management
   void add_to_freelist(HeapBlock *b);
-  FreeBlock* search_freelist(size_t length);
+  FreeBlock* search_freelist(size_t length, bool is_critical);
 
   // Iteration helpers
   void*      next_free(HeapBlock* b) const;
@@ -132,23 +132,20 @@ class CodeHeap : public CHeapObj<mtCode> {
   void  clear();                                 // clears all heap contents
 
   // Memory allocation
-  void* allocate  (size_t size);                 // allocates a block of size or returns NULL
+  void* allocate  (size_t size, bool is_critical);  // allocates a block of size or returns NULL
   void  deallocate(void* p);                     // deallocates a block
 
   // Attributes
-  void*  begin() const                           { return _memory.low (); }
+  char* low_boundary() const                     { return _memory.low_boundary (); }
-  void*  end() const                             { return _memory.high(); }
+  char* high() const                             { return _memory.high(); }
-  bool   contains(void* p) const                 { return begin() <= p && p < end(); }
+  char* high_boundary() const                    { return _memory.high_boundary(); }
+
+  bool  contains(const void* p) const            { return low_boundary() <= p && p < high(); }
   void* find_start(void* p) const;              // returns the block containing p or NULL
   size_t alignment_unit() const;                // alignment of any block
   size_t alignment_offset() const;              // offset of first byte of any block, within the enclosing alignment unit
   static size_t header_size();                  // returns the header size for each heap block
 
-  // Returns reserved area high and low addresses
-  char *low_boundary() const                     { return _memory.low_boundary (); }
-  char *high() const                             { return _memory.high(); }
-  char *high_boundary() const                    { return _memory.high_boundary(); }
-
   // Iteration
 
   // returns the first block or NULL
@@ -161,8 +158,11 @@ class CodeHeap : public CHeapObj<mtCode> {
   size_t max_capacity() const;
   size_t allocated_capacity() const;
   size_t unallocated_capacity() const            { return max_capacity() - allocated_capacity(); }
-  size_t largest_free_block() const;
 
+private:
+  size_t heap_unallocated_capacity() const;
+
+public:
   // Debugging
   void verify();
   void print()  PRODUCT_RETURN;

hotspot/src/share/vm/opto/output.cpp

@@ -1044,21 +1044,6 @@ void NonSafepointEmitter::emit_non_safepoint() {
   debug_info->end_non_safepoint(pc_offset);
 }
 
-
-
-// helper for fill_buffer bailout logic
-static void turn_off_compiler(Compile* C) {
-  if (CodeCache::largest_free_block() >= CodeCacheMinimumFreeSpace*10) {
-    // Do not turn off compilation if a single giant method has
-    // blown the code cache size.
-    C->record_failure("excessive request to CodeCache");
-  } else {
-    // Let CompilerBroker disable further compilations.
-    C->record_failure("CodeCache is full");
-  }
-}
-
-
 //------------------------------init_buffer------------------------------------
 CodeBuffer* Compile::init_buffer(uint* blk_starts) {
 
@@ -1158,7 +1143,7 @@ CodeBuffer* Compile::init_buffer(uint* blk_starts) {
 
   // Have we run out of code space?
   if ((cb->blob() == NULL) || (!CompileBroker::should_compile_new_jobs())) {
-    turn_off_compiler(this);
+    C->record_failure("CodeCache is full");
     return NULL;
   }
   // Configure the code buffer.
@@ -1476,7 +1461,7 @@ void Compile::fill_buffer(CodeBuffer* cb, uint* blk_starts) {
       // Verify that there is sufficient space remaining
       cb->insts()->maybe_expand_to_ensure_remaining(MAX_inst_size);
       if ((cb->blob() == NULL) || (!CompileBroker::should_compile_new_jobs())) {
-        turn_off_compiler(this);
+        C->record_failure("CodeCache is full");
         return;
       }
 
@@ -1633,7 +1618,7 @@ void Compile::fill_buffer(CodeBuffer* cb, uint* blk_starts) {
 
   // One last check for failed CodeBuffer::expand:
   if ((cb->blob() == NULL) || (!CompileBroker::should_compile_new_jobs())) {
-    turn_off_compiler(this);
+    C->record_failure("CodeCache is full");
     return;
   }