src/share/vm/memory/metaspace.cpp

rev 7258 : 8064611: AARCH64: Changes to HotSpot shared code
Summary: Everything except cpu/ and os_cpu/.
Reviewed-by: kvn

*** 3018,3031 ****
--- 3018,3076 ----
    assert_is_size_aligned(compressed_class_space_size(), _reserve_alignment);
  
    // Don't use large pages for the class space.
    bool large_pages = false;
  
+ #ifndef AARCH64
    ReservedSpace metaspace_rs = ReservedSpace(compressed_class_space_size(),
                                               _reserve_alignment,
                                               large_pages,
                                               requested_addr, 0);
+ #else // AARCH64
+   ReservedSpace metaspace_rs;
+ 
+   // Our compressed klass pointers may fit nicely into the lower 32
+   // bits.
+   if ((uint64_t)requested_addr + compressed_class_space_size() < 4*G) {
+     metaspace_rs = ReservedSpace(compressed_class_space_size(),
+                                              _reserve_alignment,
+                                              large_pages,
+                                              requested_addr, 0);
+   }
+ 
+   if (! metaspace_rs.is_reserved()) {
+     // Try to align metaspace so that we can decode a compressed klass
+     // with a single MOVK instruction.  We can do this iff the
+     // compressed class base is a multiple of 4G.
+     for (char *a = (char*)align_ptr_up(requested_addr, 4*G);
+          a < (char*)(1024*G);
+          a += 4*G) {
+ 
+ #if INCLUDE_CDS
+       if (UseSharedSpaces
+           && ! can_use_cds_with_metaspace_addr(a, cds_base)) {
+         // We failed to find an aligned base that will reach.  Fall
+         // back to using our requested addr.
+         metaspace_rs = ReservedSpace(compressed_class_space_size(),
+                                      _reserve_alignment,
+                                      large_pages,
+                                      requested_addr, 0);
+         break;
+       }
+ #endif
+ 
+       metaspace_rs = ReservedSpace(compressed_class_space_size(),
+                                    _reserve_alignment,
+                                    large_pages,
+                                    a, 0);
+       if (metaspace_rs.is_reserved())
+         break;
+     }
+   }
+ 
+ #endif // AARCH64
+ 
    if (!metaspace_rs.is_reserved()) {
  #if INCLUDE_CDS
      if (UseSharedSpaces) {
        size_t increment = align_size_up(1*G, _reserve_alignment);