Merge

src/os/bsd/vm/os_bsd.cpp

@@ -2325,7 +2325,9 @@ void os::large_page_init() {
 }
 
 
-char* os::reserve_memory_special(size_t bytes, char* req_addr, bool exec) {
+char* os::reserve_memory_special(size_t bytes, size_t alignment, char* req_addr, bool exec) {
+  fatal("This code is not used or maintained.");
+
   // "exec" is passed in but not used.  Creating the shared image for
   // the code cache doesn't have an SHM_X executable permission to check.
   assert(UseLargePages && UseSHM, "only for SHM large pages");
@@ -4752,3 +4754,8 @@ int os::get_core_path(char* buffer, size_t bufferSize) {
   return n;
 }
 
+#ifndef PRODUCT
+void TestReserveMemorySpecial_test() {
+  // No tests available for this platform
+}
+#endif

src/os/linux/vm/globals_linux.hpp

@@ -40,6 +40,9 @@
   product(bool, UseHugeTLBFS, false,                                    \
           "Use MAP_HUGETLB for large pages")                            \
                                                                         \
+  product(bool, UseTransparentHugePages, false,                         \
+          "Use MADV_HUGEPAGE for large pages")                          \
+                                                                        \
   product(bool, LoadExecStackDllInVMThread, true,                       \
           "Load DLLs with executable-stack attribute in the VM Thread") \
                                                                         \

src/os/linux/vm/os_linux.cpp

@@ -2720,36 +2720,7 @@ void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec,
 
 int os::Linux::commit_memory_impl(char* addr, size_t size,
                                   size_t alignment_hint, bool exec) {
-  int err;
-  if (UseHugeTLBFS && alignment_hint > (size_t)vm_page_size()) {
-    int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
-    uintptr_t res =
-      (uintptr_t) ::mmap(addr, size, prot,
-                         MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS|MAP_HUGETLB,
-                         -1, 0);
-    if (res != (uintptr_t) MAP_FAILED) {
-      if (UseNUMAInterleaving) {
-        numa_make_global(addr, size);
-      }
-      return 0;
-    }
-
-    err = errno;  // save errno from mmap() call above
-
-    if (!recoverable_mmap_error(err)) {
-      // However, it is not clear that this loss of our reserved mapping
-      // happens with large pages on Linux or that we cannot recover
-      // from the loss. For now, we just issue a warning and we don't
-      // call vm_exit_out_of_memory(). This issue is being tracked by
-      // JBS-8007074.
-      warn_fail_commit_memory(addr, size, alignment_hint, exec, err);
-//    vm_exit_out_of_memory(size, OOM_MMAP_ERROR,
-//                          "committing reserved memory.");
-    }
-    // Fall through and try to use small pages
-  }
-
-  err = os::Linux::commit_memory_impl(addr, size, exec);
+  int err = os::Linux::commit_memory_impl(addr, size, exec);
   if (err == 0) {
     realign_memory(addr, size, alignment_hint);
   }
@@ -2774,7 +2745,7 @@ void os::pd_commit_memory_or_exit(char* addr, size_t size,
 }
 
 void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
-  if (UseHugeTLBFS && alignment_hint > (size_t)vm_page_size()) {
+  if (UseTransparentHugePages && alignment_hint > (size_t)vm_page_size()) {
     // We don't check the return value: madvise(MADV_HUGEPAGE) may not
     // be supported or the memory may already be backed by huge pages.
     ::madvise(addr, bytes, MADV_HUGEPAGE);
@@ -2787,7 +2758,7 @@ void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) {
   // uncommitted at all. We don't do anything in this case to avoid creating a segment with
   // small pages on top of the SHM segment. This method always works for small pages, so we
   // allow that in any case.
-  if (alignment_hint <= (size_t)os::vm_page_size() || !UseSHM) {
+  if (alignment_hint <= (size_t)os::vm_page_size() || can_commit_large_page_memory()) {
     commit_memory(addr, bytes, alignment_hint, !ExecMem);
   }
 }
@@ -3157,11 +3128,31 @@ bool os::unguard_memory(char* addr, size_t size) {
   return linux_mprotect(addr, size, PROT_READ|PROT_WRITE);
 }
 
+bool os::Linux::transparent_huge_pages_sanity_check(bool warn, size_t page_size) {
+  bool result = false;
+  void *p = mmap(NULL, page_size * 2, PROT_READ|PROT_WRITE,
+                 MAP_ANONYMOUS|MAP_PRIVATE,
+                 -1, 0);
+  if (p != MAP_FAILED) {
+    void *aligned_p = align_ptr_up(p, page_size);
+
+    result = madvise(aligned_p, page_size, MADV_HUGEPAGE) == 0;
+
+    munmap(p, page_size * 2);
+  }
+
+  if (warn && !result) {
+    warning("TransparentHugePages is not supported by the operating system.");
+  }
+
+  return result;
+}
+
 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) {
   bool result = false;
-  void *p = mmap (NULL, page_size, PROT_READ|PROT_WRITE,
-                  MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB,
-                  -1, 0);
+  void *p = mmap(NULL, page_size, PROT_READ|PROT_WRITE,
+                 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB,
+                 -1, 0);
 
   if (p != MAP_FAILED) {
     // We don't know if this really is a huge page or not.
@@ -3182,12 +3173,10 @@ bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) {
       }
       fclose(fp);
     }
-    munmap (p, page_size);
-    if (result)
-      return true;
+    munmap(p, page_size);
   }
 
-  if (warn) {
+  if (warn && !result) {
     warning("HugeTLBFS is not supported by the operating system.");
   }
 
@@ -3235,82 +3224,114 @@ static void set_coredump_filter(void) {
 
 static size_t _large_page_size = 0;
 
-void os::large_page_init() {
-  if (!UseLargePages) {
-    UseHugeTLBFS = false;
-    UseSHM = false;
-    return;
-  }
-
-  if (FLAG_IS_DEFAULT(UseHugeTLBFS) && FLAG_IS_DEFAULT(UseSHM)) {
-    // If UseLargePages is specified on the command line try both methods,
-    // if it's default, then try only HugeTLBFS.
-    if (FLAG_IS_DEFAULT(UseLargePages)) {
-      UseHugeTLBFS = true;
-    } else {
-      UseHugeTLBFS = UseSHM = true;
-    }
-  }
+size_t os::Linux::find_large_page_size() {
+  size_t large_page_size = 0;
 
-  if (LargePageSizeInBytes) {
-    _large_page_size = LargePageSizeInBytes;
-  } else {
-    // large_page_size on Linux is used to round up heap size. x86 uses either
-    // 2M or 4M page, depending on whether PAE (Physical Address Extensions)
-    // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use
-    // page as large as 256M.
-    //
-    // Here we try to figure out page size by parsing /proc/meminfo and looking
-    // for a line with the following format:
-    //    Hugepagesize:     2048 kB
-    //
-    // If we can't determine the value (e.g. /proc is not mounted, or the text
-    // format has been changed), we'll use the largest page size supported by
-    // the processor.
+  // large_page_size on Linux is used to round up heap size. x86 uses either
+  // 2M or 4M page, depending on whether PAE (Physical Address Extensions)
+  // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use
+  // page as large as 256M.
+  //
+  // Here we try to figure out page size by parsing /proc/meminfo and looking
+  // for a line with the following format:
+  //    Hugepagesize:     2048 kB
+  //
+  // If we can't determine the value (e.g. /proc is not mounted, or the text
+  // format has been changed), we'll use the largest page size supported by
+  // the processor.
 
 #ifndef ZERO
-    _large_page_size = IA32_ONLY(4 * M) AMD64_ONLY(2 * M) IA64_ONLY(256 * M) SPARC_ONLY(4 * M)
-                       ARM_ONLY(2 * M) PPC_ONLY(4 * M);
+  large_page_size = IA32_ONLY(4 * M) AMD64_ONLY(2 * M) IA64_ONLY(256 * M) SPARC_ONLY(4 * M)
+                     ARM_ONLY(2 * M) PPC_ONLY(4 * M);
 #endif // ZERO
 
-    FILE *fp = fopen("/proc/meminfo", "r");
-    if (fp) {
-      while (!feof(fp)) {
-        int x = 0;
-        char buf[16];
-        if (fscanf(fp, "Hugepagesize: %d", &x) == 1) {
-          if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) {
-            _large_page_size = x * K;
-            break;
-          }
-        } else {
-          // skip to next line
-          for (;;) {
-            int ch = fgetc(fp);
-            if (ch == EOF || ch == (int)'\n') break;
-          }
+  FILE *fp = fopen("/proc/meminfo", "r");
+  if (fp) {
+    while (!feof(fp)) {
+      int x = 0;
+      char buf[16];
+      if (fscanf(fp, "Hugepagesize: %d", &x) == 1) {
+        if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) {
+          large_page_size = x * K;
+          break;
+        }
+      } else {
+        // skip to next line
+        for (;;) {
+          int ch = fgetc(fp);
+          if (ch == EOF || ch == (int)'\n') break;
         }
       }
-      fclose(fp);
     }
+    fclose(fp);
   }
 
-  // print a warning if any large page related flag is specified on command line
-  bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS);
+  if (!FLAG_IS_DEFAULT(LargePageSizeInBytes) && LargePageSizeInBytes != large_page_size) {
+    warning("Setting LargePageSizeInBytes has no effect on this OS. Large page size is "
+        SIZE_FORMAT "%s.", byte_size_in_proper_unit(large_page_size),
+        proper_unit_for_byte_size(large_page_size));
+  }
+
+  return large_page_size;
+}
 
+size_t os::Linux::setup_large_page_size() {
+  _large_page_size = Linux::find_large_page_size();
   const size_t default_page_size = (size_t)Linux::page_size();
   if (_large_page_size > default_page_size) {
     _page_sizes[0] = _large_page_size;
     _page_sizes[1] = default_page_size;
     _page_sizes[2] = 0;
   }
-  UseHugeTLBFS = UseHugeTLBFS &&
-                 Linux::hugetlbfs_sanity_check(warn_on_failure, _large_page_size);
 
-  if (UseHugeTLBFS)
+  return _large_page_size;
+}
+
+bool os::Linux::setup_large_page_type(size_t page_size) {
+  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;
+    }
+  }
+
+  if (UseTransparentHugePages) {
+    bool warn_on_failure = !FLAG_IS_DEFAULT(UseTransparentHugePages);
+    if (transparent_huge_pages_sanity_check(warn_on_failure, page_size)) {
+      UseHugeTLBFS = false;
+      UseSHM = false;
+      return true;
+    }
+    UseTransparentHugePages = false;
+  }
+
+  if (UseHugeTLBFS) {
+    bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS);
+    if (hugetlbfs_sanity_check(warn_on_failure, page_size)) {
+      UseSHM = false;
+      return true;
+    }
+    UseHugeTLBFS = false;
+  }
+
+  return UseSHM;
+}
+
+void os::large_page_init() {
+  if (!UseLargePages) {
+    UseHugeTLBFS = false;
+    UseTransparentHugePages = false;
     UseSHM = false;
+    return;
+  }
 
-  UseLargePages = UseHugeTLBFS || UseSHM;
+  size_t large_page_size = Linux::setup_large_page_size();
+  UseLargePages          = Linux::setup_large_page_type(large_page_size);
 
   set_coredump_filter();
 }
@@ -3319,16 +3340,22 @@ void os::large_page_init() {
 #define SHM_HUGETLB 04000
 #endif
 
-char* os::reserve_memory_special(size_t bytes, char* req_addr, bool exec) {
+char* os::Linux::reserve_memory_special_shm(size_t bytes, size_t alignment, char* req_addr, bool exec) {
   // "exec" is passed in but not used.  Creating the shared image for
   // the code cache doesn't have an SHM_X executable permission to check.
   assert(UseLargePages && UseSHM, "only for SHM large pages");
+  assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address");
+
+  if (!is_size_aligned(bytes, os::large_page_size()) || alignment > os::large_page_size()) {
+    return NULL; // Fallback to small pages.
+  }
 
   key_t key = IPC_PRIVATE;
   char *addr;
 
   bool warn_on_failure = UseLargePages &&
                         (!FLAG_IS_DEFAULT(UseLargePages) ||
+                         !FLAG_IS_DEFAULT(UseSHM) ||
                          !FLAG_IS_DEFAULT(LargePageSizeInBytes)
                         );
   char msg[128];
@@ -3376,42 +3403,219 @@ char* os::reserve_memory_special(size_t bytes, char* req_addr, bool exec) {
      return NULL;
   }
 
-  if ((addr != NULL) && UseNUMAInterleaving) {
-    numa_make_global(addr, bytes);
+  return addr;
+}
+
+static void warn_on_large_pages_failure(char* req_addr, size_t bytes, int error) {
+  assert(error == ENOMEM, "Only expect to fail if no memory is available");
+
+  bool warn_on_failure = UseLargePages &&
+      (!FLAG_IS_DEFAULT(UseLargePages) ||
+       !FLAG_IS_DEFAULT(UseHugeTLBFS) ||
+       !FLAG_IS_DEFAULT(LargePageSizeInBytes));
+
+  if (warn_on_failure) {
+    char msg[128];
+    jio_snprintf(msg, sizeof(msg), "Failed to reserve large pages memory req_addr: "
+        PTR_FORMAT " bytes: " SIZE_FORMAT " (errno = %d).", req_addr, bytes, error);
+    warning(msg);
+  }
+}
+
+char* os::Linux::reserve_memory_special_huge_tlbfs_only(size_t bytes, char* req_addr, bool exec) {
+  assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages");
+  assert(is_size_aligned(bytes, os::large_page_size()), "Unaligned size");
+  assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address");
+
+  int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
+  char* addr = (char*)::mmap(req_addr, bytes, prot,
+                             MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB,
+                             -1, 0);
+
+  if (addr == MAP_FAILED) {
+    warn_on_large_pages_failure(req_addr, bytes, errno);
+    return NULL;
+  }
+
+  assert(is_ptr_aligned(addr, os::large_page_size()), "Must be");
+
+  return addr;
+}
+
+char* os::Linux::reserve_memory_special_huge_tlbfs_mixed(size_t bytes, size_t alignment, char* req_addr, bool exec) {
+  size_t large_page_size = os::large_page_size();
+
+  assert(bytes >= large_page_size, "Shouldn't allocate large pages for small sizes");
+
+  // Allocate small pages.
+
+  char* start;
+  if (req_addr != NULL) {
+    assert(is_ptr_aligned(req_addr, alignment), "Must be");
+    assert(is_size_aligned(bytes, alignment), "Must be");
+    start = os::reserve_memory(bytes, req_addr);
+    assert(start == NULL || start == req_addr, "Must be");
+  } else {
+    start = os::reserve_memory_aligned(bytes, alignment);
+  }
+
+  if (start == NULL) {
+    return NULL;
+  }
+
+  assert(is_ptr_aligned(start, alignment), "Must be");
+
+  // os::reserve_memory_special will record this memory area.
+  // Need to release it here to prevent overlapping reservations.
+  MemTracker::record_virtual_memory_release((address)start, bytes);
+
+  char* end = start + bytes;
+
+  // Find the regions of the allocated chunk that can be promoted to large pages.
+  char* lp_start = (char*)align_ptr_up(start, large_page_size);
+  char* lp_end   = (char*)align_ptr_down(end, large_page_size);
+
+  size_t lp_bytes = lp_end - lp_start;
+
+  assert(is_size_aligned(lp_bytes, large_page_size), "Must be");
+
+  if (lp_bytes == 0) {
+    // The mapped region doesn't even span the start and the end of a large page.
+    // Fall back to allocate a non-special area.
+    ::munmap(start, end - start);
+    return NULL;
+  }
+
+  int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
+
+
+  void* result;
+
+  if (start != lp_start) {
+    result = ::mmap(start, lp_start - start, prot,
+                    MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,
+                    -1, 0);
+    if (result == MAP_FAILED) {
+      ::munmap(lp_start, end - lp_start);
+      return NULL;
+    }
+  }
+
+  result = ::mmap(lp_start, lp_bytes, prot,
+                  MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED|MAP_HUGETLB,
+                  -1, 0);
+  if (result == MAP_FAILED) {
+    warn_on_large_pages_failure(req_addr, bytes, errno);
+    // If the mmap above fails, the large pages region will be unmapped and we
+    // have regions before and after with small pages. Release these regions.
+    //
+    // |  mapped  |  unmapped  |  mapped  |
+    // ^          ^            ^          ^
+    // start      lp_start     lp_end     end
+    //
+    ::munmap(start, lp_start - start);
+    ::munmap(lp_end, end - lp_end);
+    return NULL;
   }
 
-  // The memory is committed
-  MemTracker::record_virtual_memory_reserve_and_commit((address)addr, bytes, mtNone, CALLER_PC);
+  if (lp_end != end) {
+      result = ::mmap(lp_end, end - lp_end, prot,
+                      MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,
+                      -1, 0);
+    if (result == MAP_FAILED) {
+      ::munmap(start, lp_end - start);
+      return NULL;
+    }
+  }
+
+  return start;
+}
+
+char* os::Linux::reserve_memory_special_huge_tlbfs(size_t bytes, size_t alignment, char* req_addr, bool exec) {
+  assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages");
+  assert(is_ptr_aligned(req_addr, alignment), "Must be");
+  assert(is_power_of_2(alignment), "Must be");
+  assert(is_power_of_2(os::large_page_size()), "Must be");
+  assert(bytes >= os::large_page_size(), "Shouldn't allocate large pages for small sizes");
+
+  if (is_size_aligned(bytes, os::large_page_size()) && alignment <= os::large_page_size()) {
+    return reserve_memory_special_huge_tlbfs_only(bytes, req_addr, exec);
+  } else {
+    return reserve_memory_special_huge_tlbfs_mixed(bytes, alignment, req_addr, exec);
+  }
+}
+
+char* os::reserve_memory_special(size_t bytes, size_t alignment, char* req_addr, bool exec) {
+  assert(UseLargePages, "only for large pages");
+
+  char* addr;
+  if (UseSHM) {
+    addr = os::Linux::reserve_memory_special_shm(bytes, alignment, req_addr, exec);
+  } else {
+    assert(UseHugeTLBFS, "must be");
+    addr = os::Linux::reserve_memory_special_huge_tlbfs(bytes, alignment, req_addr, exec);
+  }
+
+  if (addr != NULL) {
+    if (UseNUMAInterleaving) {
+      numa_make_global(addr, bytes);
+    }
+
+    // The memory is committed
+    MemTracker::record_virtual_memory_reserve_and_commit((address)addr, bytes, mtNone, CALLER_PC);
+  }
 
   return addr;
 }
 
+bool os::Linux::release_memory_special_shm(char* base, size_t bytes) {
+  // detaching the SHM segment will also delete it, see reserve_memory_special_shm()
+  return shmdt(base) == 0;
+}
+
+bool os::Linux::release_memory_special_huge_tlbfs(char* base, size_t bytes) {
+  return pd_release_memory(base, bytes);
+}
+
 bool os::release_memory_special(char* base, size_t bytes) {
+  assert(UseLargePages, "only for large pages");
+
   MemTracker::Tracker tkr = MemTracker::get_virtual_memory_release_tracker();
-  // detaching the SHM segment will also delete it, see reserve_memory_special()
-  int rslt = shmdt(base);
-  if (rslt == 0) {
+
+  bool res;
+  if (UseSHM) {
+    res = os::Linux::release_memory_special_shm(base, bytes);
+  } else {
+    assert(UseHugeTLBFS, "must be");
+    res = os::Linux::release_memory_special_huge_tlbfs(base, bytes);
+  }
+
+  if (res) {
     tkr.record((address)base, bytes);
-    return true;
   } else {
     tkr.discard();
-    return false;
   }
+
+  return res;
 }
 
 size_t os::large_page_size() {
   return _large_page_size;
 }
 
-// HugeTLBFS allows application to commit large page memory on demand;
-// with SysV SHM the entire memory region must be allocated as shared
+// With SysV SHM the entire memory region must be allocated as shared
 // memory.
+// HugeTLBFS allows application to commit large page memory on demand.
+// However, when committing memory with HugeTLBFS fails, the region
+// that was supposed to be committed will lose the old reservation
+// and allow other threads to steal that memory region. Because of this
+// behavior we can't commit HugeTLBFS memory.
 bool os::can_commit_large_page_memory() {
-  return UseHugeTLBFS;
+  return UseTransparentHugePages;
 }
 
 bool os::can_execute_large_page_memory() {
-  return UseHugeTLBFS;
+  return UseTransparentHugePages || UseHugeTLBFS;
 }
 
 // Reserve memory at an arbitrary address, only if that area is
@@ -4563,21 +4767,23 @@ jint os::init_2(void)
         UseNUMA = false;
       }
     }
-    // With SHM large pages we cannot uncommit a page, so there's not way
+    // With SHM and HugeTLBFS large pages we cannot uncommit a page, so there's no way
     // we can make the adaptive lgrp chunk resizing work. If the user specified
-    // both UseNUMA and UseLargePages (or UseSHM) on the command line - warn and
+    // both UseNUMA and UseLargePages (or UseSHM/UseHugeTLBFS) on the command line - warn and
     // disable adaptive resizing.
-    if (UseNUMA && UseLargePages && UseSHM) {
-      if (!FLAG_IS_DEFAULT(UseNUMA)) {
-        if (FLAG_IS_DEFAULT(UseLargePages) && FLAG_IS_DEFAULT(UseSHM)) {
+    if (UseNUMA && UseLargePages && !can_commit_large_page_memory()) {
+      if (FLAG_IS_DEFAULT(UseNUMA)) {
+        UseNUMA = false;
+      } else {
+        if (FLAG_IS_DEFAULT(UseLargePages) &&
+            FLAG_IS_DEFAULT(UseSHM) &&
+            FLAG_IS_DEFAULT(UseHugeTLBFS)) {
           UseLargePages = false;
         } else {
-          warning("UseNUMA is not fully compatible with SHM large pages, disabling adaptive resizing");
+          warning("UseNUMA is not fully compatible with SHM/HugeTLBFS large pages, disabling adaptive resizing");
           UseAdaptiveSizePolicy = false;
           UseAdaptiveNUMAChunkSizing = false;
         }
-      } else {
-        UseNUMA = false;
       }
     }
     if (!UseNUMA && ForceNUMA) {
@@ -5848,3 +6054,149 @@ void MemNotifyThread::start() {
 }
 
 #endif // JAVASE_EMBEDDED
+
+
+/////////////// Unit tests ///////////////
+
+#ifndef PRODUCT
+
+#define test_log(...) \
+  do {\
+    if (VerboseInternalVMTests) { \
+      tty->print_cr(__VA_ARGS__); \
+      tty->flush(); \
+    }\
+  } while (false)
+
+class TestReserveMemorySpecial : AllStatic {
+ public:
+  static void small_page_write(void* addr, size_t size) {
+    size_t page_size = os::vm_page_size();
+
+    char* end = (char*)addr + size;
+    for (char* p = (char*)addr; p < end; p += page_size) {
+      *p = 1;
+    }
+  }
+
+  static void test_reserve_memory_special_huge_tlbfs_only(size_t size) {
+    if (!UseHugeTLBFS) {
+      return;
+    }
+
+    test_log("test_reserve_memory_special_huge_tlbfs_only(" SIZE_FORMAT ")", size);
+
+    char* addr = os::Linux::reserve_memory_special_huge_tlbfs_only(size, NULL, false);
+
+    if (addr != NULL) {
+      small_page_write(addr, size);
+
+      os::Linux::release_memory_special_huge_tlbfs(addr, size);
+    }
+  }
+
+  static void test_reserve_memory_special_huge_tlbfs_only() {
+    if (!UseHugeTLBFS) {
+      return;
+    }
+
+    size_t lp = os::large_page_size();
+
+    for (size_t size = lp; size <= lp * 10; size += lp) {
+      test_reserve_memory_special_huge_tlbfs_only(size);
+    }
+  }
+
+  static void test_reserve_memory_special_huge_tlbfs_mixed(size_t size, size_t alignment) {
+    if (!UseHugeTLBFS) {
+        return;
+    }
+
+    test_log("test_reserve_memory_special_huge_tlbfs_mixed(" SIZE_FORMAT ", " SIZE_FORMAT ")",
+        size, alignment);
+
+    assert(size >= os::large_page_size(), "Incorrect input to test");
+
+    char* addr = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, NULL, false);
+
+    if (addr != NULL) {
+      small_page_write(addr, size);
+
+      os::Linux::release_memory_special_huge_tlbfs(addr, size);
+    }
+  }
+
+  static void test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(size_t size) {
+    size_t lp = os::large_page_size();
+    size_t ag = os::vm_allocation_granularity();
+
+    for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) {
+      test_reserve_memory_special_huge_tlbfs_mixed(size, alignment);
+    }
+  }
+
+  static void test_reserve_memory_special_huge_tlbfs_mixed() {
+    size_t lp = os::large_page_size();
+    size_t ag = os::vm_allocation_granularity();
+
+    test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp);
+    test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp + ag);
+    test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp + lp / 2);
+    test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp * 2);
+    test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp * 2 + ag);
+    test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp * 2 - ag);
+    test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp * 2 + lp / 2);
+    test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp * 10);
+    test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp * 10 + lp / 2);
+  }
+
+  static void test_reserve_memory_special_huge_tlbfs() {
+    if (!UseHugeTLBFS) {
+      return;
+    }
+
+    test_reserve_memory_special_huge_tlbfs_only();
+    test_reserve_memory_special_huge_tlbfs_mixed();
+  }
+
+  static void test_reserve_memory_special_shm(size_t size, size_t alignment) {
+    if (!UseSHM) {
+      return;
+    }
+
+    test_log("test_reserve_memory_special_shm(" SIZE_FORMAT ", " SIZE_FORMAT ")", size, alignment);
+
+    char* addr = os::Linux::reserve_memory_special_shm(size, alignment, NULL, false);
+
+    if (addr != NULL) {
+      assert(is_ptr_aligned(addr, alignment), "Check");
+      assert(is_ptr_aligned(addr, os::large_page_size()), "Check");
+
+      small_page_write(addr, size);
+
+      os::Linux::release_memory_special_shm(addr, size);
+    }
+  }
+
+  static void test_reserve_memory_special_shm() {
+    size_t lp = os::large_page_size();
+    size_t ag = os::vm_allocation_granularity();
+
+    for (size_t size = ag; size < lp * 3; size += ag) {
+      for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) {
+        test_reserve_memory_special_shm(size, alignment);
+      }
+    }
+  }
+
+  static void test() {
+    test_reserve_memory_special_huge_tlbfs();
+    test_reserve_memory_special_shm();
+  }
+};
+
+void TestReserveMemorySpecial_test() {
+  TestReserveMemorySpecial::test();
+}
+
+#endif

src/os/linux/vm/os_linux.hpp

@@ -32,6 +32,7 @@ typedef int (*pthread_getattr_func_type) (pthread_t, pthread_attr_t *);
 
 class Linux {
   friend class os;
+  friend class TestReserveMemorySpecial;
 
   // For signal-chaining
 #define MAXSIGNUM 32
@@ -92,8 +93,21 @@ class Linux {
   static void rebuild_cpu_to_node_map();
   static GrowableArray<int>* cpu_to_node()    { return _cpu_to_node; }
 
+  static size_t find_large_page_size();
+  static size_t setup_large_page_size();
+
+  static bool setup_large_page_type(size_t page_size);
+  static bool transparent_huge_pages_sanity_check(bool warn, size_t pages_size);
   static bool hugetlbfs_sanity_check(bool warn, size_t page_size);
 
+  static char* reserve_memory_special_shm(size_t bytes, size_t alignment, char* req_addr, bool exec);
+  static char* reserve_memory_special_huge_tlbfs(size_t bytes, size_t alignment, char* req_addr, bool exec);
+  static char* reserve_memory_special_huge_tlbfs_only(size_t bytes, char* req_addr, bool exec);
+  static char* reserve_memory_special_huge_tlbfs_mixed(size_t bytes, size_t alignment, char* req_addr, bool exec);
+
+  static bool release_memory_special_shm(char* base, size_t bytes);
+  static bool release_memory_special_huge_tlbfs(char* base, size_t bytes);
+
   static void print_full_memory_info(outputStream* st);
   static void print_distro_info(outputStream* st);
   static void print_libversion_info(outputStream* st);

src/os/solaris/vm/os_solaris.cpp

@@ -3385,7 +3385,7 @@ bool os::Solaris::setup_large_pages(caddr_t start, size_t bytes, size_t align) {
   return true;
 }
 
-char* os::reserve_memory_special(size_t size, char* addr, bool exec) {
+char* os::reserve_memory_special(size_t size, size_t alignment, char* addr, bool exec) {
   fatal("os::reserve_memory_special should not be called on Solaris.");
   return NULL;
 }
@@ -6601,3 +6601,9 @@ int os::get_core_path(char* buffer, size_t bufferSize) {
 
   return strlen(buffer);
 }
+
+#ifndef PRODUCT
+void TestReserveMemorySpecial_test() {
+  // No tests available for this platform
+}
+#endif

src/os/windows/vm/os_windows.cpp

@@ -3156,7 +3156,12 @@ bool os::can_execute_large_page_memory() {
   return true;
 }
 
-char* os::reserve_memory_special(size_t bytes, char* addr, bool exec) {
+char* os::reserve_memory_special(size_t bytes, size_t alignment, char* addr, bool exec) {
+  assert(UseLargePages, "only for large pages");
+
+  if (!is_size_aligned(bytes, os::large_page_size()) || alignment > os::large_page_size()) {
+    return NULL; // Fallback to small pages.
+  }
 
   const DWORD prot = exec ? PAGE_EXECUTE_READWRITE : PAGE_READWRITE;
   const DWORD flags = MEM_RESERVE | MEM_COMMIT | MEM_LARGE_PAGES;
@@ -5638,3 +5643,9 @@ BOOL os::Advapi32Dll::AdvapiAvailable() {
 }
 
 #endif
+
+#ifndef PRODUCT
+void TestReserveMemorySpecial_test() {
+  // No tests available for this platform
+}
+#endif

src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp

@@ -2006,10 +2006,12 @@ jint G1CollectedHeap::initialize() {
 
   size_t init_byte_size = collector_policy()->initial_heap_byte_size();
   size_t max_byte_size = collector_policy()->max_heap_byte_size();
+  size_t heap_alignment = collector_policy()->max_alignment();
 
   // Ensure that the sizes are properly aligned.
   Universe::check_alignment(init_byte_size, HeapRegion::GrainBytes, "g1 heap");
   Universe::check_alignment(max_byte_size, HeapRegion::GrainBytes, "g1 heap");
+  Universe::check_alignment(max_byte_size, heap_alignment, "g1 heap");
 
   _cg1r = new ConcurrentG1Refine(this);
 
@@ -2026,12 +2028,8 @@ jint G1CollectedHeap::initialize() {
   // If this happens then we could end up using a non-optimal
   // compressed oops mode.
 
-  // Since max_byte_size is aligned to the size of a heap region (checked
-  // above).
-  Universe::check_alignment(max_byte_size, HeapRegion::GrainBytes, "g1 heap");
-
   ReservedSpace heap_rs = Universe::reserve_heap(max_byte_size,
-                                                 HeapRegion::GrainBytes);
+                                                 heap_alignment);
 
   // It is important to do this in a way such that concurrent readers can't
   // temporarily think something is in the heap.  (I've actually seen this

src/share/vm/gc_implementation/g1/g1CollectorPolicy.cpp

@@ -313,7 +313,8 @@ G1CollectorPolicy::G1CollectorPolicy() :
 void G1CollectorPolicy::initialize_flags() {
   set_min_alignment(HeapRegion::GrainBytes);
   size_t card_table_alignment = GenRemSet::max_alignment_constraint(rem_set_name());
-  set_max_alignment(MAX2(card_table_alignment, min_alignment()));
+  size_t page_size = UseLargePages ? os::large_page_size() : os::vm_page_size();
+  set_max_alignment(MAX3(card_table_alignment, min_alignment(), page_size));
   if (SurvivorRatio < 1) {
     vm_exit_during_initialization("Invalid survivor ratio specified");
   }

src/share/vm/memory/collectorPolicy.cpp

@@ -193,6 +193,8 @@ size_t GenCollectorPolicy::compute_max_alignment() {
       alignment = lcm(os::large_page_size(), alignment);
   }
 
+  assert(alignment >= min_alignment(), "Must be");
+
   return alignment;
 }
 

src/share/vm/memory/genCollectedHeap.cpp

@@ -95,13 +95,13 @@ jint GenCollectedHeap::initialize() {
   guarantee(HeapWordSize == wordSize, "HeapWordSize must equal wordSize");
 
   // The heap must be at least as aligned as generations.
-  size_t alignment = Generation::GenGrain;
+  size_t gen_alignment = Generation::GenGrain;
 
   _gen_specs = gen_policy()->generations();
 
   // Make sure the sizes are all aligned.
   for (i = 0; i < _n_gens; i++) {
-    _gen_specs[i]->align(alignment);
+    _gen_specs[i]->align(gen_alignment);
   }
 
   // Allocate space for the heap.
@@ -109,9 +109,11 @@ jint GenCollectedHeap::initialize() {
   char* heap_address;
   size_t total_reserved = 0;
   int n_covered_regions = 0;
-  ReservedSpace heap_rs(0);
+  ReservedSpace heap_rs;
 
-  heap_address = allocate(alignment, &total_reserved,
+  size_t heap_alignment = collector_policy()->max_alignment();
+
+  heap_address = allocate(heap_alignment, &total_reserved,
                           &n_covered_regions, &heap_rs);
 
   if (!heap_rs.is_reserved()) {
@@ -168,6 +170,8 @@ char* GenCollectedHeap::allocate(size_t alignment,
   const size_t pageSize = UseLargePages ?
       os::large_page_size() : os::vm_page_size();
 
+  assert(alignment % pageSize == 0, "Must be");
+
   for (int i = 0; i < _n_gens; i++) {
     total_reserved += _gen_specs[i]->max_size();
     if (total_reserved < _gen_specs[i]->max_size()) {
@@ -175,24 +179,17 @@ char* GenCollectedHeap::allocate(size_t alignment,
     }
     n_covered_regions += _gen_specs[i]->n_covered_regions();
   }
-  assert(total_reserved % pageSize == 0,
-         err_msg("Gen size; total_reserved=" SIZE_FORMAT ", pageSize="
-                 SIZE_FORMAT, total_reserved, pageSize));
+  assert(total_reserved % alignment == 0,
+         err_msg("Gen size; total_reserved=" SIZE_FORMAT ", alignment="
+                 SIZE_FORMAT, total_reserved, alignment));
 
   // Needed until the cardtable is fixed to have the right number
   // of covered regions.
   n_covered_regions += 2;
 
-  if (UseLargePages) {
-    assert(total_reserved != 0, "total_reserved cannot be 0");
-    total_reserved = round_to(total_reserved, os::large_page_size());
-    if (total_reserved < os::large_page_size()) {
-      vm_exit_during_initialization(overflow_msg);
-    }
-  }
+  *_total_reserved = total_reserved;
+  *_n_covered_regions = n_covered_regions;
 
-      *_total_reserved = total_reserved;
-      *_n_covered_regions = n_covered_regions;
   *heap_rs = Universe::reserve_heap(total_reserved, alignment);
   return heap_rs->base();
 }

src/share/vm/memory/metaspace.cpp

@@ -345,7 +345,7 @@ class VirtualSpaceNode : public CHeapObj<mtClass> {
 };
 
   // byte_size is the size of the associated virtualspace.
-VirtualSpaceNode::VirtualSpaceNode(size_t byte_size) : _top(NULL), _next(NULL), _rs(0), _container_count(0) {
+VirtualSpaceNode::VirtualSpaceNode(size_t byte_size) : _top(NULL), _next(NULL), _rs(), _container_count(0) {
   // align up to vm allocation granularity
   byte_size = align_size_up(byte_size, os::vm_allocation_granularity());
 

src/share/vm/memory/universe.cpp

@@ -681,17 +681,23 @@ static const uint64_t NarrowOopHeapMax = (uint64_t(max_juint) + 1);
 // 32Gb
 // OopEncodingHeapMax == NarrowOopHeapMax << LogMinObjAlignmentInBytes;
 
-char* Universe::preferred_heap_base(size_t heap_size, NARROW_OOP_MODE mode) {
+char* Universe::preferred_heap_base(size_t heap_size, size_t alignment, NARROW_OOP_MODE mode) {
+  assert(is_size_aligned((size_t)OopEncodingHeapMax, alignment), "Must be");
+  assert(is_size_aligned((size_t)NarrowOopHeapMax, alignment), "Must be");
+  assert(is_size_aligned(heap_size, alignment), "Must be");
+
+  uintx heap_base_min_address_aligned = align_size_up(HeapBaseMinAddress, alignment);
+
   size_t base = 0;
 #ifdef _LP64
   if (UseCompressedOops) {
     assert(mode == UnscaledNarrowOop  ||
            mode == ZeroBasedNarrowOop ||
            mode == HeapBasedNarrowOop, "mode is invalid");
-    const size_t total_size = heap_size + HeapBaseMinAddress;
+    const size_t total_size = heap_size + heap_base_min_address_aligned;
     // Return specified base for the first request.
     if (!FLAG_IS_DEFAULT(HeapBaseMinAddress) && (mode == UnscaledNarrowOop)) {
-      base = HeapBaseMinAddress;
+      base = heap_base_min_address_aligned;
 
     // If the total size is small enough to allow UnscaledNarrowOop then
     // just use UnscaledNarrowOop.
@@ -742,6 +748,8 @@ char* Universe::preferred_heap_base(size_t heap_size, NARROW_OOP_MODE mode) {
     }
   }
 #endif
+
+  assert(is_ptr_aligned((char*)base, alignment), "Must be");
   return (char*)base; // also return NULL (don't care) for 32-bit VM
 }
 
@@ -867,27 +875,33 @@ ReservedSpace Universe::reserve_heap(size_t heap_size, size_t alignment) {
   size_t total_reserved = align_size_up(heap_size, alignment);
   assert(!UseCompressedOops || (total_reserved <= (OopEncodingHeapMax - os::vm_page_size())),
       "heap size is too big for compressed oops");
-  char* addr = Universe::preferred_heap_base(total_reserved, Universe::UnscaledNarrowOop);
 
-  ReservedHeapSpace total_rs(total_reserved, alignment, UseLargePages, addr);
+  bool use_large_pages = UseLargePages && is_size_aligned(alignment, os::large_page_size());
+  assert(!UseLargePages
+      || UseParallelOldGC
+      || use_large_pages, "Wrong alignment to use large pages");
+
+  char* addr = Universe::preferred_heap_base(total_reserved, alignment, Universe::UnscaledNarrowOop);
+
+  ReservedHeapSpace total_rs(total_reserved, alignment, use_large_pages, addr);
 
   if (UseCompressedOops) {
     if (addr != NULL && !total_rs.is_reserved()) {
       // Failed to reserve at specified address - the requested memory
       // region is taken already, for example, by 'java' launcher.
       // Try again to reserver heap higher.
-      addr = Universe::preferred_heap_base(total_reserved, Universe::ZeroBasedNarrowOop);
+      addr = Universe::preferred_heap_base(total_reserved, alignment, Universe::ZeroBasedNarrowOop);
 
       ReservedHeapSpace total_rs0(total_reserved, alignment,
-                                  UseLargePages, addr);
+          use_large_pages, addr);
 
       if (addr != NULL && !total_rs0.is_reserved()) {
         // Failed to reserve at specified address again - give up.
-        addr = Universe::preferred_heap_base(total_reserved, Universe::HeapBasedNarrowOop);
+        addr = Universe::preferred_heap_base(total_reserved, alignment, Universe::HeapBasedNarrowOop);
         assert(addr == NULL, "");
 
         ReservedHeapSpace total_rs1(total_reserved, alignment,
-                                    UseLargePages, addr);
+            use_large_pages, addr);
         total_rs = total_rs1;
       } else {
         total_rs = total_rs0;

src/share/vm/memory/universe.hpp

@@ -346,7 +346,7 @@ class Universe: AllStatic {
   };
   static NARROW_OOP_MODE narrow_oop_mode();
   static const char* narrow_oop_mode_to_string(NARROW_OOP_MODE mode);
-  static char*    preferred_heap_base(size_t heap_size, NARROW_OOP_MODE mode);
+  static char*    preferred_heap_base(size_t heap_size, size_t alignment, NARROW_OOP_MODE mode);
   static char*    preferred_metaspace_base(size_t heap_size, NARROW_OOP_MODE mode);
   static address  narrow_oop_base()                       { return  _narrow_oop._base; }
   static bool  is_narrow_oop_base(void* addr)             { return (narrow_oop_base() == (address)addr); }

src/share/vm/prims/jni.cpp

@@ -5045,9 +5045,15 @@ _JNI_IMPORT_OR_EXPORT_ jint JNICALL JNI_GetDefaultJavaVMInitArgs(void *args_) {
   tty->print_cr("Running test: " #unit_test_function_call); \
   unit_test_function_call
 
+// Forward declaration
+void TestReservedSpace_test();
+void TestReserveMemorySpecial_test();
+
 void execute_internal_vm_tests() {
   if (ExecuteInternalVMTests) {
     tty->print_cr("Running internal VM tests");
+    run_unit_test(TestReservedSpace_test());
+    run_unit_test(TestReserveMemorySpecial_test());
     run_unit_test(GlobalDefinitions::test_globals());
     run_unit_test(GCTimerAllTest::all());
     run_unit_test(arrayOopDesc::test_max_array_length());

src/share/vm/runtime/globals.hpp

@@ -1933,6 +1933,9 @@ class CommandLineFlags {
   notproduct(bool, ExecuteInternalVMTests, false,                           \
           "Enable execution of internal VM tests.")                         \
                                                                             \
+  notproduct(bool, VerboseInternalVMTests, false,                           \
+          "Turn on logging for internal VM tests.")                         \
+                                                                            \
   product_pd(bool, UseTLAB, "Use thread-local object allocation")           \
                                                                             \
   product_pd(bool, ResizeTLAB,                                              \

src/share/vm/runtime/os.hpp

@@ -328,8 +328,8 @@ class os: AllStatic {
 
   static char*  non_memory_address_word();
   // reserve, commit and pin the entire memory region
-  static char*  reserve_memory_special(size_t size, char* addr = NULL,
-                bool executable = false);
+  static char*  reserve_memory_special(size_t size, size_t alignment,
+                                       char* addr, bool executable);
   static bool   release_memory_special(char* addr, size_t bytes);
   static void   large_page_init();
   static size_t large_page_size();

src/share/vm/runtime/virtualspace.cpp

@@ -42,8 +42,19 @@
 
 
 // ReservedSpace
+
+// Dummy constructor
+ReservedSpace::ReservedSpace() : _base(NULL), _size(0), _noaccess_prefix(0),
+    _alignment(0), _special(false), _executable(false) {
+}
+
 ReservedSpace::ReservedSpace(size_t size) {
-  initialize(size, 0, false, NULL, 0, false);
+  size_t page_size = os::page_size_for_region(size, size, 1);
+  bool large_pages = page_size != (size_t)os::vm_page_size();
+  // Don't force the alignment to be large page aligned,
+  // since that will waste memory.
+  size_t alignment = os::vm_allocation_granularity();
+  initialize(size, alignment, large_pages, NULL, 0, false);
 }
 
 ReservedSpace::ReservedSpace(size_t size, size_t alignment,
@@ -129,16 +140,18 @@ void ReservedSpace::initialize(size_t size, size_t alignment, bool large,
 
   if (special) {
 
-    base = os::reserve_memory_special(size, requested_address, executable);
+    base = os::reserve_memory_special(size, alignment, requested_address, executable);
 
     if (base != NULL) {
       if (failed_to_reserve_as_requested(base, requested_address, size, true)) {
         // OS ignored requested address. Try different address.
         return;
       }
-      // Check alignment constraints
+      // Check alignment constraints.
       assert((uintptr_t) base % alignment == 0,
-             "Large pages returned a non-aligned address");
+             err_msg("Large pages returned a non-aligned address, base: "
+                 PTR_FORMAT " alignment: " PTR_FORMAT,
+                 base, (void*)(uintptr_t)alignment));
       _special = true;
     } else {
       // failed; try to reserve regular memory below
@@ -715,4 +728,188 @@ void VirtualSpace::print() {
   tty->print_cr(" - [low_b, high_b]: [" INTPTR_FORMAT ", " INTPTR_FORMAT "]",  low_boundary(), high_boundary());
 }
 
+
+/////////////// Unit tests ///////////////
+
+#ifndef PRODUCT
+
+#define test_log(...) \
+  do {\
+    if (VerboseInternalVMTests) { \
+      tty->print_cr(__VA_ARGS__); \
+      tty->flush(); \
+    }\
+  } while (false)
+
+class TestReservedSpace : AllStatic {
+ public:
+  static void small_page_write(void* addr, size_t size) {
+    size_t page_size = os::vm_page_size();
+
+    char* end = (char*)addr + size;
+    for (char* p = (char*)addr; p < end; p += page_size) {
+      *p = 1;
+    }
+  }
+
+  static void release_memory_for_test(ReservedSpace rs) {
+    if (rs.special()) {
+      guarantee(os::release_memory_special(rs.base(), rs.size()), "Shouldn't fail");
+    } else {
+      guarantee(os::release_memory(rs.base(), rs.size()), "Shouldn't fail");
+    }
+  }
+
+  static void test_reserved_space1(size_t size, size_t alignment) {
+    test_log("test_reserved_space1(%p)", (void*) (uintptr_t) size);
+
+    assert(is_size_aligned(size, alignment), "Incorrect input parameters");
+
+    ReservedSpace rs(size,          // size
+                     alignment,     // alignment
+                     UseLargePages, // large
+                     NULL,          // requested_address
+                     0);            // noacces_prefix
+
+    test_log(" rs.special() == %d", rs.special());
+
+    assert(rs.base() != NULL, "Must be");
+    assert(rs.size() == size, "Must be");
+
+    assert(is_ptr_aligned(rs.base(), alignment), "aligned sizes should always give aligned addresses");
+    assert(is_size_aligned(rs.size(), alignment), "aligned sizes should always give aligned addresses");
+
+    if (rs.special()) {
+      small_page_write(rs.base(), size);
+    }
+
+    release_memory_for_test(rs);
+  }
+
+  static void test_reserved_space2(size_t size) {
+    test_log("test_reserved_space2(%p)", (void*)(uintptr_t)size);
+
+    assert(is_size_aligned(size, os::vm_allocation_granularity()), "Must be at least AG aligned");
+
+    ReservedSpace rs(size);
+
+    test_log(" rs.special() == %d", rs.special());
+
+    assert(rs.base() != NULL, "Must be");
+    assert(rs.size() == size, "Must be");
+
+    if (rs.special()) {
+      small_page_write(rs.base(), size);
+    }
+
+    release_memory_for_test(rs);
+  }
+
+  static void test_reserved_space3(size_t size, size_t alignment, bool maybe_large) {
+    test_log("test_reserved_space3(%p, %p, %d)",
+        (void*)(uintptr_t)size, (void*)(uintptr_t)alignment, maybe_large);
+
+    assert(is_size_aligned(size, os::vm_allocation_granularity()), "Must be at least AG aligned");
+    assert(is_size_aligned(size, alignment), "Must be at least aligned against alignment");
+
+    bool large = maybe_large && UseLargePages && size >= os::large_page_size();
+
+    ReservedSpace rs(size, alignment, large, false);
+
+    test_log(" rs.special() == %d", rs.special());
+
+    assert(rs.base() != NULL, "Must be");
+    assert(rs.size() == size, "Must be");
+
+    if (rs.special()) {
+      small_page_write(rs.base(), size);
+    }
+
+    release_memory_for_test(rs);
+  }
+
+
+  static void test_reserved_space1() {
+    size_t size = 2 * 1024 * 1024;
+    size_t ag   = os::vm_allocation_granularity();
+
+    test_reserved_space1(size,      ag);
+    test_reserved_space1(size * 2,  ag);
+    test_reserved_space1(size * 10, ag);
+  }
+
+  static void test_reserved_space2() {
+    size_t size = 2 * 1024 * 1024;
+    size_t ag = os::vm_allocation_granularity();
+
+    test_reserved_space2(size * 1);
+    test_reserved_space2(size * 2);
+    test_reserved_space2(size * 10);
+    test_reserved_space2(ag);
+    test_reserved_space2(size - ag);
+    test_reserved_space2(size);
+    test_reserved_space2(size + ag);
+    test_reserved_space2(size * 2);
+    test_reserved_space2(size * 2 - ag);
+    test_reserved_space2(size * 2 + ag);
+    test_reserved_space2(size * 3);
+    test_reserved_space2(size * 3 - ag);
+    test_reserved_space2(size * 3 + ag);
+    test_reserved_space2(size * 10);
+    test_reserved_space2(size * 10 + size / 2);
+  }
+
+  static void test_reserved_space3() {
+    size_t ag = os::vm_allocation_granularity();
+
+    test_reserved_space3(ag,      ag    , false);
+    test_reserved_space3(ag * 2,  ag    , false);
+    test_reserved_space3(ag * 3,  ag    , false);
+    test_reserved_space3(ag * 2,  ag * 2, false);
+    test_reserved_space3(ag * 4,  ag * 2, false);
+    test_reserved_space3(ag * 8,  ag * 2, false);
+    test_reserved_space3(ag * 4,  ag * 4, false);
+    test_reserved_space3(ag * 8,  ag * 4, false);
+    test_reserved_space3(ag * 16, ag * 4, false);
+
+    if (UseLargePages) {
+      size_t lp = os::large_page_size();
+
+      // Without large pages
+      test_reserved_space3(lp,     ag * 4, false);
+      test_reserved_space3(lp * 2, ag * 4, false);
+      test_reserved_space3(lp * 4, ag * 4, false);
+      test_reserved_space3(lp,     lp    , false);
+      test_reserved_space3(lp * 2, lp    , false);
+      test_reserved_space3(lp * 3, lp    , false);
+      test_reserved_space3(lp * 2, lp * 2, false);
+      test_reserved_space3(lp * 4, lp * 2, false);
+      test_reserved_space3(lp * 8, lp * 2, false);
+
+      // With large pages
+      test_reserved_space3(lp, ag * 4    , true);
+      test_reserved_space3(lp * 2, ag * 4, true);
+      test_reserved_space3(lp * 4, ag * 4, true);
+      test_reserved_space3(lp, lp        , true);
+      test_reserved_space3(lp * 2, lp    , true);
+      test_reserved_space3(lp * 3, lp    , true);
+      test_reserved_space3(lp * 2, lp * 2, true);
+      test_reserved_space3(lp * 4, lp * 2, true);
+      test_reserved_space3(lp * 8, lp * 2, true);
+    }
+  }
+
+  static void test_reserved_space() {
+    test_reserved_space1();
+    test_reserved_space2();
+    test_reserved_space3();
+  }
+};
+
+void TestReservedSpace_test() {
+  TestReservedSpace::test_reserved_space();
+}
+
+#endif // PRODUCT
+
 #endif

src/share/vm/runtime/virtualspace.hpp

@@ -53,6 +53,7 @@ class ReservedSpace VALUE_OBJ_CLASS_SPEC {
 
  public:
   // Constructor
+  ReservedSpace();
   ReservedSpace(size_t size);
   ReservedSpace(size_t size, size_t alignment, bool large,
                 char* requested_address = NULL,

src/share/vm/services/memTracker.hpp

@@ -87,6 +87,8 @@ class MemTracker : AllStatic {
         MEMFLAGS flags, address pc = 0, Thread* thread = NULL) { }
    static inline void record_virtual_memory_commit(address addr, size_t size,
         address pc = 0, Thread* thread = NULL) { }
+   static inline void record_virtual_memory_release(address addr, size_t size,
+        Thread* thread = NULL) { }
    static inline void record_virtual_memory_type(address base, MEMFLAGS flags,
         Thread* thread = NULL) { }
    static inline Tracker get_realloc_tracker() { return _tkr; }
@@ -372,6 +374,13 @@ class MemTracker : AllStatic {
     tkr.record(addr, size, flags, pc);
   }
 
+  static inline void record_virtual_memory_release(address addr, size_t size,
+      Thread* thread = NULL) {
+    if (is_on()) {
+      Tracker tkr(Tracker::Release, thread);
+      tkr.record(addr, size);
+    }
+  }
 
   // record memory type on virtual memory base address
   static inline void record_virtual_memory_type(address base, MEMFLAGS flags,

src/share/vm/utilities/globalDefinitions.hpp

@@ -402,6 +402,14 @@ const jlong CompressedKlassPointersBase = NOT_LP64(0) LP64_ONLY(CONST64(0x800000
 
 #define align_size_up_(size, alignment) (((size) + ((alignment) - 1)) & ~((alignment) - 1))
 
+inline bool is_size_aligned(size_t size, size_t alignment) {
+  return align_size_up_(size, alignment) == size;
+}
+
+inline bool is_ptr_aligned(void* ptr, size_t alignment) {
+  return align_size_up_((intptr_t)ptr, (intptr_t)alignment) == (intptr_t)ptr;
+}
+
 inline intptr_t align_size_up(intptr_t size, intptr_t alignment) {
   return align_size_up_(size, alignment);
 }
@@ -414,6 +422,14 @@ inline intptr_t align_size_down(intptr_t size, intptr_t alignment) {
 
 #define is_size_aligned_(size, alignment) ((size) == (align_size_up_(size, alignment)))
 
+inline void* align_ptr_up(void* ptr, size_t alignment) {
+  return (void*)align_size_up((intptr_t)ptr, (intptr_t)alignment);
+}
+
+inline void* align_ptr_down(void* ptr, size_t alignment) {
+  return (void*)align_size_down((intptr_t)ptr, (intptr_t)alignment);
+}
+
 // Align objects by rounding up their size, in HeapWord units.
 
 #define align_object_size_(size) align_size_up_(size, MinObjAlignment)