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      1 /*
      2  * Copyright (C) 2015 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #include "immune_spaces.h"
     18 
     19 #include <tuple>
     20 #include <vector>
     21 
     22 #include "base/logging.h"  // For VLOG.
     23 #include "gc/space/space-inl.h"
     24 #include "mirror/object.h"
     25 #include "oat_file.h"
     26 
     27 namespace art {
     28 namespace gc {
     29 namespace collector {
     30 
     31 void ImmuneSpaces::Reset() {
     32   spaces_.clear();
     33   largest_immune_region_.Reset();
     34 }
     35 
     36 void ImmuneSpaces::CreateLargestImmuneRegion() {
     37   uintptr_t best_begin = 0u;
     38   uintptr_t best_end = 0u;
     39   uintptr_t best_heap_size = 0u;
     40   uintptr_t cur_begin = 0u;
     41   uintptr_t cur_end = 0u;
     42   uintptr_t cur_heap_size = 0u;
     43   using Interval = std::tuple</*start*/uintptr_t, /*end*/uintptr_t, /*is_heap*/bool>;
     44   std::vector<Interval> intervals;
     45   for (space::ContinuousSpace* space : GetSpaces()) {
     46     uintptr_t space_begin = reinterpret_cast<uintptr_t>(space->Begin());
     47     uintptr_t space_end = reinterpret_cast<uintptr_t>(space->Limit());
     48     if (space->IsImageSpace()) {
     49       // For the boot image, the boot oat file is always directly after. For app images it may not
     50       // be if the app image was mapped at a random address.
     51       space::ImageSpace* image_space = space->AsImageSpace();
     52       // Update the end to include the other non-heap sections.
     53       space_end = RoundUp(reinterpret_cast<uintptr_t>(image_space->GetImageEnd()), kPageSize);
     54       // For the app image case, GetOatFileBegin is where the oat file was mapped during image
     55       // creation, the actual oat file could be somewhere else.
     56       const OatFile* const image_oat_file = image_space->GetOatFile();
     57       if (image_oat_file != nullptr) {
     58         intervals.push_back(Interval(reinterpret_cast<uintptr_t>(image_oat_file->Begin()),
     59                                      reinterpret_cast<uintptr_t>(image_oat_file->End()),
     60                                      /*image*/false));
     61       }
     62     }
     63     intervals.push_back(Interval(space_begin, space_end, /*is_heap*/true));
     64   }
     65   std::sort(intervals.begin(), intervals.end());
     66   // Intervals are already sorted by begin, if a new interval begins at the end of the current
     67   // region then we append, otherwise we restart the current interval. To prevent starting an
     68   // interval on an oat file, ignore oat files that are not extending an existing interval.
     69   // If the total number of image bytes in the current interval is larger than the current best
     70   // one, then we set the best one to be the current one.
     71   for (const Interval& interval : intervals) {
     72     const uintptr_t begin = std::get<0>(interval);
     73     const uintptr_t end = std::get<1>(interval);
     74     const bool is_heap = std::get<2>(interval);
     75     VLOG(collector) << "Interval " << reinterpret_cast<const void*>(begin) << "-"
     76                     << reinterpret_cast<const void*>(end) << " is_heap=" << is_heap;
     77     DCHECK_GE(end, begin);
     78     DCHECK_GE(begin, cur_end);
     79     // New interval is not at the end of the current one, start a new interval if we are a heap
     80     // interval. Otherwise continue since we never start a new region with non image intervals.
     81     if (begin != cur_end) {
     82       if (!is_heap) {
     83         continue;
     84       }
     85       // Not extending, reset the region.
     86       cur_begin = begin;
     87       cur_heap_size = 0;
     88     }
     89     cur_end = end;
     90     if (is_heap) {
     91       // Only update if the total number of image bytes is greater than the current best one.
     92       // We don't want to count the oat file bytes since these contain no java objects.
     93       cur_heap_size += end - begin;
     94       if (cur_heap_size > best_heap_size) {
     95         best_begin = cur_begin;
     96         best_end = cur_end;
     97         best_heap_size = cur_heap_size;
     98       }
     99     }
    100   }
    101   largest_immune_region_.SetBegin(reinterpret_cast<mirror::Object*>(best_begin));
    102   largest_immune_region_.SetEnd(reinterpret_cast<mirror::Object*>(best_end));
    103   VLOG(collector) << "Immune region " << largest_immune_region_.Begin() << "-"
    104                   << largest_immune_region_.End();
    105 }
    106 
    107 void ImmuneSpaces::AddSpace(space::ContinuousSpace* space) {
    108   DCHECK(spaces_.find(space) == spaces_.end()) << *space;
    109   // Bind live to mark bitmap if necessary.
    110   if (space->GetLiveBitmap() != space->GetMarkBitmap()) {
    111     CHECK(space->IsContinuousMemMapAllocSpace());
    112     space->AsContinuousMemMapAllocSpace()->BindLiveToMarkBitmap();
    113   }
    114   spaces_.insert(space);
    115   CreateLargestImmuneRegion();
    116 }
    117 
    118 bool ImmuneSpaces::CompareByBegin::operator()(space::ContinuousSpace* a, space::ContinuousSpace* b)
    119     const {
    120   return a->Begin() < b->Begin();
    121 }
    122 
    123 bool ImmuneSpaces::ContainsSpace(space::ContinuousSpace* space) const {
    124   return spaces_.find(space) != spaces_.end();
    125 }
    126 
    127 }  // namespace collector
    128 }  // namespace gc
    129 }  // namespace art
    130