src/hotspot/share/gc/z/zMemory.cpp

*** 1,7 ****
  /*
!  * Copyright (c) 2015, 2017, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.
--- 1,7 ----
  /*
!  * Copyright (c) 2015, 2019, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.
*** 47,56 ****
--- 47,80 ----
  
    // Out of memory
    return UINTPTR_MAX;
  }
  
+ uintptr_t ZMemoryManager::alloc_from_front_at_most(size_t size, size_t* allocated) {
+   ZMemory* area = _freelist.first();
+   if (area != NULL) {
+     if (area->size() <= size) {
+       // Smaller than or equal to requested, remove area
+       const uintptr_t start = area->start();
+       *allocated = area->size();
+       _freelist.remove(area);
+       delete area;
+       return start;
+     } else {
+       // Larger than requested, shrink area
+       const uintptr_t start = area->start();
+       area->shrink_from_front(size);
+       *allocated = size;
+       return start;
+     }
+   }
+ 
+   // Out of memory
+   *allocated = 0;
+   return UINTPTR_MAX;
+ }
+ 
  uintptr_t ZMemoryManager::alloc_from_back(size_t size) {
    ZListReverseIterator<ZMemory> iter(&_freelist);
    for (ZMemory* area; iter.next(&area);) {
      if (area->size() >= size) {
        if (area->size() == size) {
*** 69,78 ****
--- 93,125 ----
  
    // Out of memory
    return UINTPTR_MAX;
  }
  
+ uintptr_t ZMemoryManager::alloc_from_back_at_most(size_t size, size_t* allocated) {
+   ZMemory* area = _freelist.last();
+   if (area != NULL) {
+     if (area->size() <= size) {
+       // Smaller than or equal to requested, remove area
+       const uintptr_t start = area->start();
+       *allocated = area->size();
+       _freelist.remove(area);
+       delete area;
+       return start;
+     } else {
+       // Larger than requested, shrink area
+       area->shrink_from_back(size);
+       *allocated = size;
+       return area->end();
+     }
+   }
+ 
+   // Out of memory
+   *allocated = 0;
+   return UINTPTR_MAX;
+ }
+ 
  void ZMemoryManager::free(uintptr_t start, size_t size) {
    assert(start != UINTPTR_MAX, "Invalid address");
    const uintptr_t end = start + size;
  
    ZListIterator<ZMemory> iter(&_freelist);