Mercurial > jdk8-mips64-public > hotspot / file revision

 /*

  * Copyright (c) 2001, 2012, 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.

  *

  * This code is distributed in the hope that it will be useful, but WITHOUT

  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

  * version 2 for more details (a copy is included in the LICENSE file that

  * accompanied this code).

  *

  * You should have received a copy of the GNU General Public License version

  * 2 along with this work; if not, write to the Free Software Foundation,

  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

  *

  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

  * or visit www.oracle.com if you need additional information or have any

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  */

 #include "precompiled.hpp"

 #ifndef SERIALGC

 #include "gc_implementation/shared/mutableSpace.hpp"

 #include "gc_implementation/shared/spaceDecorator.hpp"

 #include "oops/oop.inline.hpp"

 #include "runtime/safepoint.hpp"

 #include "runtime/thread.hpp"

 #endif

 MutableSpace::MutableSpace(size_t alignment): ImmutableSpace(), _top(NULL), _alignment(alignment) {

   assert(MutableSpace::alignment() >= 0 &&

          MutableSpace::alignment() % os::vm_page_size() == 0,

          "Space should be aligned");

   _mangler = new MutableSpaceMangler(this);

 }

 MutableSpace::~MutableSpace() {

   delete _mangler;

 }

 void MutableSpace::numa_setup_pages(MemRegion mr, bool clear_space) {

   if (!mr.is_empty()) {

     size_t page_size = UseLargePages ? alignment() : os::vm_page_size();

     HeapWord *start = (HeapWord*)round_to((intptr_t) mr.start(), page_size);

     HeapWord *end =  (HeapWord*)round_down((intptr_t) mr.end(), page_size);

     if (end > start) {

       size_t size = pointer_delta(end, start, sizeof(char));

       if (clear_space) {

         // Prefer page reallocation to migration.

         os::free_memory((char*)start, size, page_size);

       }

       os::numa_make_global((char*)start, size);

     }

   }

 }

 void MutableSpace::pretouch_pages(MemRegion mr) {

   for (volatile char *p = (char*)mr.start(); p < (char*)mr.end(); p += os::vm_page_size()) {

     char t = *p; *p = t;

   }

 }

 void MutableSpace::initialize(MemRegion mr,

                               bool clear_space,

                               bool mangle_space,

                               bool setup_pages) {

   assert(Universe::on_page_boundary(mr.start()) && Universe::on_page_boundary(mr.end()),

          "invalid space boundaries");

   if (setup_pages && (UseNUMA || AlwaysPreTouch)) {

     // The space may move left and right or expand/shrink.

     // We'd like to enforce the desired page placement.

     MemRegion head, tail;

     if (last_setup_region().is_empty()) {

       // If it's the first initialization don't limit the amount of work.

       head = mr;

       tail = MemRegion(mr.end(), mr.end());

     } else {

       // Is there an intersection with the address space?

       MemRegion intersection = last_setup_region().intersection(mr);

       if (intersection.is_empty()) {

         intersection = MemRegion(mr.end(), mr.end());

       }

       // All the sizes below are in words.

       size_t head_size = 0, tail_size = 0;

       if (mr.start() <= intersection.start()) {

         head_size = pointer_delta(intersection.start(), mr.start());

       }

       if(intersection.end() <= mr.end()) {

         tail_size = pointer_delta(mr.end(), intersection.end());

       }

       // Limit the amount of page manipulation if necessary.

       if (NUMASpaceResizeRate > 0 && !AlwaysPreTouch) {

         const size_t change_size = head_size + tail_size;

         const float setup_rate_words = NUMASpaceResizeRate >> LogBytesPerWord;

         head_size = MIN2((size_t)(setup_rate_words * head_size / change_size),

                          head_size);

         tail_size = MIN2((size_t)(setup_rate_words * tail_size / change_size),

                          tail_size);

       }

       head = MemRegion(intersection.start() - head_size, intersection.start());

       tail = MemRegion(intersection.end(), intersection.end() + tail_size);

     }

     assert(mr.contains(head) && mr.contains(tail), "Sanity");

     if (UseNUMA) {

       numa_setup_pages(head, clear_space);

       numa_setup_pages(tail, clear_space);

     }

     if (AlwaysPreTouch) {

       pretouch_pages(head);

       pretouch_pages(tail);

     }

     // Remember where we stopped so that we can continue later.

     set_last_setup_region(MemRegion(head.start(), tail.end()));

   }

   set_bottom(mr.start());

   set_end(mr.end());

   if (clear_space) {

     clear(mangle_space);

   }

 }

 void MutableSpace::clear(bool mangle_space) {

   set_top(bottom());

   if (ZapUnusedHeapArea && mangle_space) {

     mangle_unused_area();

   }

 }

 #ifndef PRODUCT

 void MutableSpace::check_mangled_unused_area(HeapWord* limit) {

   mangler()->check_mangled_unused_area(limit);

 }

 void MutableSpace::check_mangled_unused_area_complete() {

   mangler()->check_mangled_unused_area_complete();

 }

 // Mangle only the unused space that has not previously

 // been mangled and that has not been allocated since being

 // mangled.

 void MutableSpace::mangle_unused_area() {

   mangler()->mangle_unused_area();

 }

 void MutableSpace::mangle_unused_area_complete() {

   mangler()->mangle_unused_area_complete();

 }

 void MutableSpace::mangle_region(MemRegion mr) {

   SpaceMangler::mangle_region(mr);

 }

 void MutableSpace::set_top_for_allocations(HeapWord* v) {

   mangler()->set_top_for_allocations(v);

 }

 void MutableSpace::set_top_for_allocations() {

   mangler()->set_top_for_allocations(top());

 }

 #endif

 // This version requires locking. */

 HeapWord* MutableSpace::allocate(size_t size) {

   assert(Heap_lock->owned_by_self() ||

          (SafepointSynchronize::is_at_safepoint() &&

           Thread::current()->is_VM_thread()),

          "not locked");

   HeapWord* obj = top();

   if (pointer_delta(end(), obj) >= size) {

     HeapWord* new_top = obj + size;

     set_top(new_top);

     assert(is_object_aligned((intptr_t)obj) && is_object_aligned((intptr_t)new_top),

            "checking alignment");

     return obj;

   } else {

     return NULL;

   }

 }

 // This version is lock-free.

 HeapWord* MutableSpace::cas_allocate(size_t size) {

   do {

     HeapWord* obj = top();

     if (pointer_delta(end(), obj) >= size) {

       HeapWord* new_top = obj + size;

       HeapWord* result = (HeapWord*)Atomic::cmpxchg_ptr(new_top, top_addr(), obj);

       // result can be one of two:

       //  the old top value: the exchange succeeded

       //  otherwise: the new value of the top is returned.

       if (result != obj) {

         continue; // another thread beat us to the allocation, try again

       }

       assert(is_object_aligned((intptr_t)obj) && is_object_aligned((intptr_t)new_top),

              "checking alignment");

       return obj;

     } else {

       return NULL;

     }

   } while (true);

 }

 // Try to deallocate previous allocation. Returns true upon success.

 bool MutableSpace::cas_deallocate(HeapWord *obj, size_t size) {

   HeapWord* expected_top = obj + size;

   return (HeapWord*)Atomic::cmpxchg_ptr(obj, top_addr(), expected_top) == expected_top;

 }

 void MutableSpace::oop_iterate(ExtendedOopClosure* cl) {

   HeapWord* obj_addr = bottom();

   HeapWord* t = top();

   // Could call objects iterate, but this is easier.

   while (obj_addr < t) {

     obj_addr += oop(obj_addr)->oop_iterate(cl);

   }

 }

 void MutableSpace::oop_iterate_no_header(OopClosure* cl) {

   HeapWord* obj_addr = bottom();

   HeapWord* t = top();

   // Could call objects iterate, but this is easier.

   while (obj_addr < t) {

     obj_addr += oop(obj_addr)->oop_iterate_no_header(cl);

   }

 }

 void MutableSpace::object_iterate(ObjectClosure* cl) {

   HeapWord* p = bottom();

   while (p < top()) {

     cl->do_object(oop(p));

     p += oop(p)->size();

   }

 }

 void MutableSpace::print_short() const { print_short_on(tty); }

 void MutableSpace::print_short_on( outputStream* st) const {

   st->print(" space " SIZE_FORMAT "K, %d%% used", capacity_in_bytes() / K,

             (int) ((double) used_in_bytes() * 100 / capacity_in_bytes()));

 }

 void MutableSpace::print() const { print_on(tty); }

 void MutableSpace::print_on(outputStream* st) const {

   MutableSpace::print_short_on(st);

   st->print_cr(" [" INTPTR_FORMAT "," INTPTR_FORMAT "," INTPTR_FORMAT ")",

                  bottom(), top(), end());

 }

 void MutableSpace::verify() {

   HeapWord* p = bottom();

   HeapWord* t = top();

   HeapWord* prev_p = NULL;

   while (p < t) {

     oop(p)->verify();

     prev_p = p;

     p += oop(p)->size();

   }

   guarantee(p == top(), "end of last object must match end of space");

 }