src/hotspot/share/memory/metaspace.cpp

rev 54061 : 8244847: Linux/PPC: runtime/CompressedOops/CompressedClassPointers: smallHeapTest fails
Reviewed-by: stuefe, mdoerr

*** 1044,1059 ****
    assert_is_aligned(compressed_class_space_size(), _reserve_alignment);
  
    // Don't use large pages for the class space.
    bool large_pages = false;
  
! #if !(defined(AARCH64) || defined(AIX))
    ReservedSpace metaspace_rs = ReservedSpace(compressed_class_space_size(),
                                               _reserve_alignment,
                                               large_pages,
                                               requested_addr);
! #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) {
--- 1044,1060 ----
    assert_is_aligned(compressed_class_space_size(), _reserve_alignment);
  
    // Don't use large pages for the class space.
    bool large_pages = false;
  
! #if !(defined(AARCH64) || defined(PPC64))
    ReservedSpace metaspace_rs = ReservedSpace(compressed_class_space_size(),
                                               _reserve_alignment,
                                               large_pages,
                                               requested_addr);
! #else // AARCH64 || PPC64
! 
    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) {
*** 1067,1076 ****
--- 1068,1084 ----
      // Aarch64: 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.
      // Aix: Search for a place where we can find memory. If we need to load
      // the base, 4G alignment is helpful, too.
+     // PPC64: smaller heaps up to 2g will be mapped just below 4g. Then the
+     // attempt to place the compressed class space just after the heap fails on
+     // Linux 4.1.42 and higher because the launcher is loaded at 4g
+     // (ELF_ET_DYN_BASE). In that case we reach here and search the address space
+     // below 32g to get a zerobased CCS. For simplicity we reuse the search
+     // strategy for AARCH64.
+ 
      size_t increment = AARCH64_ONLY(4*)G;
      for (char *a = align_up(requested_addr, increment);
           a < (char*)(1024*G);
           a += increment) {
        if (a == (char *)(32*G)) {
*** 1098,1108 ****
        if (metaspace_rs.is_reserved())
          break;
      }
    }
  
! #endif // AARCH64
  
    if (!metaspace_rs.is_reserved()) {
  #if INCLUDE_CDS
      if (UseSharedSpaces) {
        size_t increment = align_up(1*G, _reserve_alignment);
--- 1106,1116 ----
        if (metaspace_rs.is_reserved())
          break;
      }
    }
  
! #endif // AARCH64 || PPC64
  
    if (!metaspace_rs.is_reserved()) {
  #if INCLUDE_CDS
      if (UseSharedSpaces) {
        size_t increment = align_up(1*G, _reserve_alignment);