jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/g1/heapRegionSeq.cpp@f95d63e2154a (annotated)

src/share/vm/gc_implementation/g1/heapRegionSeq.cpp@f95d63e2154a (annotated)

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

Tue, 23 Nov 2010 13:22:55 -0800

author: stefank
date: Tue, 23 Nov 2010 13:22:55 -0800
changeset 2314: f95d63e2154a
parent 2241: 72a161e62cc4
child 2453: 2250ee17e258
permissions: -rw-r--r--

6989984: Use standard include model for Hospot
Summary: Replaced MakeDeps and the includeDB files with more standardized solutions.
Reviewed-by: coleenp, kvn, kamg

 /*
  * Copyright (c) 2001, 2010, 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
  * questions.
  *
  */
 #include "precompiled.hpp"
 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
 #include "gc_implementation/g1/heapRegionSeq.hpp"
 #include "memory/allocation.hpp"
 // Local to this file.
 static int orderRegions(HeapRegion** hr1p, HeapRegion** hr2p) {
   if ((*hr1p)->end() <= (*hr2p)->bottom()) return -1;
   else if ((*hr2p)->end() <= (*hr1p)->bottom()) return 1;
   else if (*hr1p == *hr2p) return 0;
   else {
     assert(false, "We should never compare distinct overlapping regions.");
   }
   return 0;
 }
 HeapRegionSeq::HeapRegionSeq(const size_t max_size) :
   _alloc_search_start(0),
   // The line below is the worst bit of C++ hackery I've ever written
   // (Detlefs, 11/23).  You should think of it as equivalent to
   // "_regions(100, true)": initialize the growable array and inform it
   // that it should allocate its elem array(s) on the C heap.
   //
   // The first argument, however, is actually a comma expression
   // (set_allocation_type(this, C_HEAP), 100). The purpose of the
   // set_allocation_type() call is to replace the default allocation
   // type for embedded objects STACK_OR_EMBEDDED with C_HEAP. It will
   // allow to pass the assert in GenericGrowableArray() which checks
   // that a growable array object must be on C heap if elements are.
   //
   // Note: containing object is allocated on C heap since it is CHeapObj.
   //
   _regions((ResourceObj::set_allocation_type((address)&_regions,
                                              ResourceObj::C_HEAP),
             (int)max_size),
            true),
   _next_rr_candidate(0),
   _seq_bottom(NULL)
 {}
 // Private methods.
 HeapWord*
 HeapRegionSeq::alloc_obj_from_region_index(int ind, size_t word_size) {
   assert(G1CollectedHeap::isHumongous(word_size),
          "Allocation size should be humongous");
   int cur = ind;
   int first = cur;
   size_t sumSizes = 0;
   while (cur < _regions.length() && sumSizes < word_size) {
     // Loop invariant:
     //  For all i in [first, cur):
     //       _regions.at(i)->is_empty()
     //    && _regions.at(i) is contiguous with its predecessor, if any
     //  && sumSizes is the sum of the sizes of the regions in the interval
     //       [first, cur)
     HeapRegion* curhr = _regions.at(cur);
     if (curhr->is_empty()
         && (first == cur
             || (_regions.at(cur-1)->end() ==
                 curhr->bottom()))) {
       sumSizes += curhr->capacity() / HeapWordSize;
     } else {
       first = cur + 1;
       sumSizes = 0;
     }
     cur++;
   }
   if (sumSizes >= word_size) {
     _alloc_search_start = cur;
     // We need to initialize the region(s) we just discovered. This is
     // a bit tricky given that it can happen concurrently with
     // refinement threads refining cards on these regions and
     // potentially wanting to refine the BOT as they are scanning
     // those cards (this can happen shortly after a cleanup; see CR
     // 6991377). So we have to set up the region(s) carefully and in
     // a specific order.
     // Currently, allocs_are_zero_filled() returns false. The zero
     // filling infrastructure will be going away soon (see CR 6977804).
     // So no need to do anything else here.
     bool zf = G1CollectedHeap::heap()->allocs_are_zero_filled();
     assert(!zf, "not supported");
     // This will be the "starts humongous" region.
     HeapRegion* first_hr = _regions.at(first);
     {
       MutexLockerEx x(ZF_mon, Mutex::_no_safepoint_check_flag);
       first_hr->set_zero_fill_allocated();
     }
     // The header of the new object will be placed at the bottom of
     // the first region.
     HeapWord* new_obj = first_hr->bottom();
     // This will be the new end of the first region in the series that
     // should also match the end of the last region in the seriers.
     // (Note: sumSizes = "region size" x "number of regions we found").
     HeapWord* new_end = new_obj + sumSizes;
     // This will be the new top of the first region that will reflect
     // this allocation.
     HeapWord* new_top = new_obj + word_size;
     // First, we need to zero the header of the space that we will be
     // allocating. When we update top further down, some refinement
     // threads might try to scan the region. By zeroing the header we
     // ensure that any thread that will try to scan the region will
     // come across the zero klass word and bail out.
     //
     // NOTE: It would not have been correct to have used
     // CollectedHeap::fill_with_object() and make the space look like
     // an int array. The thread that is doing the allocation will
     // later update the object header to a potentially different array
     // type and, for a very short period of time, the klass and length
     // fields will be inconsistent. This could cause a refinement
     // thread to calculate the object size incorrectly.
     Copy::fill_to_words(new_obj, oopDesc::header_size(), 0);
     // We will set up the first region as "starts humongous". This
     // will also update the BOT covering all the regions to reflect
     // that there is a single object that starts at the bottom of the
     // first region.
     first_hr->set_startsHumongous(new_end);
     // Then, if there are any, we will set up the "continues
     // humongous" regions.
     HeapRegion* hr = NULL;
     for (int i = first + 1; i < cur; ++i) {
       hr = _regions.at(i);
       {
         MutexLockerEx x(ZF_mon, Mutex::_no_safepoint_check_flag);
         hr->set_zero_fill_allocated();
       }
       hr->set_continuesHumongous(first_hr);
     }
     // If we have "continues humongous" regions (hr != NULL), then the
     // end of the last one should match new_end.
     assert(hr == NULL || hr->end() == new_end, "sanity");
     // Up to this point no concurrent thread would have been able to
     // do any scanning on any region in this series. All the top
     // fields still point to bottom, so the intersection between
     // [bottom,top] and [card_start,card_end] will be empty. Before we
     // update the top fields, we'll do a storestore to make sure that
     // no thread sees the update to top before the zeroing of the
     // object header and the BOT initialization.
     OrderAccess::storestore();
     // Now that the BOT and the object header have been initialized,
     // we can update top of the "starts humongous" region.
     assert(first_hr->bottom() < new_top && new_top <= first_hr->end(),
            "new_top should be in this region");
     first_hr->set_top(new_top);
     // Now, we will update the top fields of the "continues humongous"
     // regions. The reason we need to do this is that, otherwise,
     // these regions would look empty and this will confuse parts of
     // G1. For example, the code that looks for a consecutive number
     // of empty regions will consider them empty and try to
     // re-allocate them. We can extend is_empty() to also include
     // !continuesHumongous(), but it is easier to just update the top
     // fields here.
     hr = NULL;
     for (int i = first + 1; i < cur; ++i) {
       hr = _regions.at(i);
       if ((i + 1) == cur) {
         // last continues humongous region
         assert(hr->bottom() < new_top && new_top <= hr->end(),
                "new_top should fall on this region");
         hr->set_top(new_top);
       } else {
         // not last one
         assert(new_top > hr->end(), "new_top should be above this region");
         hr->set_top(hr->end());
       }
     }
     // If we have continues humongous regions (hr != NULL), then the
     // end of the last one should match new_end and its top should
     // match new_top.
     assert(hr == NULL ||
            (hr->end() == new_end && hr->top() == new_top), "sanity");
     return new_obj;
   } else {
     // If we started from the beginning, we want to know why we can't alloc.
     return NULL;
   }
 }
 void HeapRegionSeq::print_empty_runs() {
   int empty_run = 0;
   int n_empty = 0;
   int empty_run_start;
   for (int i = 0; i < _regions.length(); i++) {
     HeapRegion* r = _regions.at(i);
     if (r->continuesHumongous()) continue;
     if (r->is_empty()) {
       assert(!r->isHumongous(), "H regions should not be empty.");
       if (empty_run == 0) empty_run_start = i;
       empty_run++;
       n_empty++;
     } else {
       if (empty_run > 0) {
         gclog_or_tty->print("  %d:%d", empty_run_start, empty_run);
         empty_run = 0;
       }
     }
   }
   if (empty_run > 0) {
     gclog_or_tty->print(" %d:%d", empty_run_start, empty_run);
   }
   gclog_or_tty->print_cr(" [tot = %d]", n_empty);
 }
 int HeapRegionSeq::find(HeapRegion* hr) {
   // FIXME: optimized for adjacent regions of fixed size.
   int ind = hr->hrs_index();
   if (ind != -1) {
     assert(_regions.at(ind) == hr, "Mismatch");
   }
   return ind;
 }
 // Public methods.
 void HeapRegionSeq::insert(HeapRegion* hr) {
   assert(!_regions.is_full(), "Too many elements in HeapRegionSeq");
   if (_regions.length() == 0
       || _regions.top()->end() <= hr->bottom()) {
     hr->set_hrs_index(_regions.length());
     _regions.append(hr);
   } else {
     _regions.append(hr);
     _regions.sort(orderRegions);
     for (int i = 0; i < _regions.length(); i++) {
       _regions.at(i)->set_hrs_index(i);
     }
   }
   char* bot = (char*)_regions.at(0)->bottom();
   if (_seq_bottom == NULL || bot < _seq_bottom) _seq_bottom = bot;
 }
 size_t HeapRegionSeq::length() {
   return _regions.length();
 }
 size_t HeapRegionSeq::free_suffix() {
   size_t res = 0;
   int first = _regions.length() - 1;
   int cur = first;
   while (cur >= 0 &&
          (_regions.at(cur)->is_empty()
           && (first == cur
               || (_regions.at(cur+1)->bottom() ==
                   _regions.at(cur)->end())))) {
       res++;
       cur--;
   }
   return res;
 }
 HeapWord* HeapRegionSeq::obj_allocate(size_t word_size) {
   int cur = _alloc_search_start;
   // Make sure "cur" is a valid index.
   assert(cur >= 0, "Invariant.");
   HeapWord* res = alloc_obj_from_region_index(cur, word_size);
   if (res == NULL)
     res = alloc_obj_from_region_index(0, word_size);
   return res;
 }
 void HeapRegionSeq::iterate(HeapRegionClosure* blk) {
   iterate_from((HeapRegion*)NULL, blk);
 }
 // The first argument r is the heap region at which iteration begins.
 // This operation runs fastest when r is NULL, or the heap region for
 // which a HeapRegionClosure most recently returned true, or the
 // heap region immediately to its right in the sequence.  In all
 // other cases a linear search is required to find the index of r.
 void HeapRegionSeq::iterate_from(HeapRegion* r, HeapRegionClosure* blk) {
   // :::: FIXME ::::
   // Static cache value is bad, especially when we start doing parallel
   // remembered set update. For now just don't cache anything (the
   // code in the def'd out blocks).
 #if 0
   static int cached_j = 0;
 #endif
   int len = _regions.length();
   int j = 0;
   // Find the index of r.
   if (r != NULL) {
 #if 0
     assert(cached_j >= 0, "Invariant.");
     if ((cached_j < len) && (r == _regions.at(cached_j))) {
       j = cached_j;
     } else if ((cached_j + 1 < len) && (r == _regions.at(cached_j + 1))) {
       j = cached_j + 1;
     } else {
       j = find(r);
 #endif
       if (j < 0) {
         j = 0;
       }
 #if 0
     }
 #endif
   }
   int i;
   for (i = j; i < len; i += 1) {
     int res = blk->doHeapRegion(_regions.at(i));
     if (res) {
 #if 0
       cached_j = i;
 #endif
       blk->incomplete();
       return;
     }
   }
   for (i = 0; i < j; i += 1) {
     int res = blk->doHeapRegion(_regions.at(i));
     if (res) {
 #if 0
       cached_j = i;
 #endif
       blk->incomplete();
       return;
     }
   }
 }
 void HeapRegionSeq::iterate_from(int idx, HeapRegionClosure* blk) {
   int len = _regions.length();
   int i;
   for (i = idx; i < len; i++) {
     if (blk->doHeapRegion(_regions.at(i))) {
       blk->incomplete();
       return;
     }
   }
   for (i = 0; i < idx; i++) {
     if (blk->doHeapRegion(_regions.at(i))) {
       blk->incomplete();
       return;
     }
   }
 }
 MemRegion HeapRegionSeq::shrink_by(size_t shrink_bytes,
                                    size_t& num_regions_deleted) {
   assert(shrink_bytes % os::vm_page_size() == 0, "unaligned");
   assert(shrink_bytes % HeapRegion::GrainBytes == 0, "unaligned");
   if (_regions.length() == 0) {
     num_regions_deleted = 0;
     return MemRegion();
   }
   int j = _regions.length() - 1;
   HeapWord* end = _regions.at(j)->end();
   HeapWord* last_start = end;
   while (j >= 0 && shrink_bytes > 0) {
     HeapRegion* cur = _regions.at(j);
     // We have to leave humongous regions where they are,
     // and work around them.
     if (cur->isHumongous()) {
       return MemRegion(last_start, end);
     }
     assert(cur == _regions.top(), "Should be top");
     if (!cur->is_empty()) break;
     cur->reset_zero_fill();
     shrink_bytes -= cur->capacity();
     num_regions_deleted++;
     _regions.pop();
     last_start = cur->bottom();
     // We need to delete these somehow, but can't currently do so here: if
     // we do, the ZF thread may still access the deleted region.  We'll
     // leave this here as a reminder that we have to do something about
     // this.
     // delete cur;
     j--;
   }
   return MemRegion(last_start, end);
 }
 class PrintHeapRegionClosure : public  HeapRegionClosure {
 public:
   bool doHeapRegion(HeapRegion* r) {
     gclog_or_tty->print(PTR_FORMAT ":", r);
     r->print();
     return false;
   }
 };
 void HeapRegionSeq::print() {
   PrintHeapRegionClosure cl;
   iterate(&cl);
 }

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/gc_implementation/g1/heapRegionSeq.cpp@f95d63e2154a (annotated)

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