src/hotspot/share/runtime/os.hpp

*** 108,117 ****
--- 108,118 ----
    }
  
    static char*  pd_reserve_memory(size_t bytes, char* addr = 0,
                                    size_t alignment_hint = 0);
    static char*  pd_attempt_reserve_memory_at(size_t bytes, char* addr);
+   static char*  pd_attempt_reserve_memory_at(size_t bytes, char* addr, int file_desc);
    static void   pd_split_reserved_memory(char *base, size_t size,
                                        size_t split, bool realloc);
    static bool   pd_commit_memory(char* addr, size_t bytes, bool executable);
    static bool   pd_commit_memory(char* addr, size_t size, size_t alignment_hint,
                                   bool executable);
*** 300,314 ****
                                                    const char* base,
                                                    const size_t size);
  
    static int    vm_allocation_granularity();
    static char*  reserve_memory(size_t bytes, char* addr = 0,
!                                size_t alignment_hint = 0);
    static char*  reserve_memory(size_t bytes, char* addr,
                                 size_t alignment_hint, MEMFLAGS flags);
!   static char*  reserve_memory_aligned(size_t size, size_t alignment);
!   static char*  attempt_reserve_memory_at(size_t bytes, char* addr);
    static void   split_reserved_memory(char *base, size_t size,
                                        size_t split, bool realloc);
    static bool   commit_memory(char* addr, size_t bytes, bool executable);
    static bool   commit_memory(char* addr, size_t size, size_t alignment_hint,
                                bool executable);
--- 301,315 ----
                                                    const char* base,
                                                    const size_t size);
  
    static int    vm_allocation_granularity();
    static char*  reserve_memory(size_t bytes, char* addr = 0,
!                                size_t alignment_hint = 0, int file_desc = -1);
    static char*  reserve_memory(size_t bytes, char* addr,
                                 size_t alignment_hint, MEMFLAGS flags);
!   static char*  reserve_memory_aligned(size_t size, size_t alignment, int file_desc = -1);
!   static char*  attempt_reserve_memory_at(size_t bytes, char* addr, int file_desc = -1);
    static void   split_reserved_memory(char *base, size_t size,
                                        size_t split, bool realloc);
    static bool   commit_memory(char* addr, size_t bytes, bool executable);
    static bool   commit_memory(char* addr, size_t size, size_t alignment_hint,
                                bool executable);
*** 335,344 ****
--- 336,353 ----
    static bool   guard_memory(char* addr, size_t bytes);
    static bool   unguard_memory(char* addr, size_t bytes);
    static bool   create_stack_guard_pages(char* addr, size_t bytes);
    static bool   pd_create_stack_guard_pages(char* addr, size_t bytes);
    static bool   remove_stack_guard_pages(char* addr, size_t bytes);
+   // Helper function to create a new file with template jvmheap.XXXXXX.
+   // Returns a valid fd on success or else returns -1
+   static int create_file_for_heap(const char* dir);
+   // Map memory to the file referred by fd. This function is slightly different from map_memory()
+   // and is added to be used for implementation of -XX:AllocateHeapAt
+   static char* map_memory_to_file(char* base, size_t size, int fd);
+   // Replace existing reserved memory with file mapping
+   static char* replace_existing_mapping_with_file_mapping(char* base, size_t size, int fd);
  
    static char*  map_memory(int fd, const char* file_name, size_t file_offset,
                             char *addr, size_t bytes, bool read_only = false,
                             bool allow_exec = false);
    static char*  remap_memory(int fd, const char* file_name, size_t file_offset,