| /* |
| * Copyright (C) 2010 Google Inc. All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions are |
| * met: |
| * |
| * * Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * * Redistributions in binary form must reproduce the above |
| * copyright notice, this list of conditions and the following disclaimer |
| * in the documentation and/or other materials provided with the |
| * distribution. |
| * * Neither the name of Google Inc. nor the names of its |
| * contributors may be used to endorse or promote products derived from |
| * this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| #include "core/timing/MemoryInfo.h" |
| |
| #include "core/frame/LocalFrame.h" |
| #include "core/frame/Settings.h" |
| #include "platform/RuntimeEnabledFeatures.h" |
| #include "wtf/CurrentTime.h" |
| #include "wtf/MathExtras.h" |
| #include "wtf/ThreadSpecific.h" |
| #include <limits> |
| #include <v8.h> |
| |
| namespace blink { |
| |
| static const double TwentyMinutesInSeconds = 20 * 60; |
| |
| static void getHeapSize(HeapInfo& info) |
| { |
| v8::HeapStatistics heapStatistics; |
| v8::Isolate::GetCurrent()->GetHeapStatistics(&heapStatistics); |
| info.usedJSHeapSize = heapStatistics.used_heap_size(); |
| info.totalJSHeapSize = heapStatistics.total_physical_size(); |
| info.jsHeapSizeLimit = heapStatistics.heap_size_limit(); |
| } |
| |
| class HeapSizeCache { |
| WTF_MAKE_NONCOPYABLE(HeapSizeCache); USING_FAST_MALLOC(HeapSizeCache); |
| public: |
| HeapSizeCache() |
| : m_lastUpdateTime(monotonicallyIncreasingTime() - TwentyMinutesInSeconds) |
| { |
| } |
| |
| void getCachedHeapSize(HeapInfo& info) |
| { |
| maybeUpdate(); |
| info = m_info; |
| } |
| |
| static HeapSizeCache& forCurrentThread() |
| { |
| DEFINE_THREAD_SAFE_STATIC_LOCAL(ThreadSpecific<HeapSizeCache>, heapSizeCache, new ThreadSpecific<HeapSizeCache>); |
| return *heapSizeCache; |
| } |
| |
| private: |
| void maybeUpdate() |
| { |
| // We rate-limit queries to once every twenty minutes to make it more difficult |
| // for attackers to compare memory usage before and after some event. |
| double now = monotonicallyIncreasingTime(); |
| if (now - m_lastUpdateTime >= TwentyMinutesInSeconds) { |
| update(); |
| m_lastUpdateTime = now; |
| } |
| } |
| |
| void update() |
| { |
| getHeapSize(m_info); |
| m_info.usedJSHeapSize = quantizeMemorySize(m_info.usedJSHeapSize); |
| m_info.totalJSHeapSize = quantizeMemorySize(m_info.totalJSHeapSize); |
| m_info.jsHeapSizeLimit = quantizeMemorySize(m_info.jsHeapSizeLimit); |
| } |
| |
| double m_lastUpdateTime; |
| |
| HeapInfo m_info; |
| }; |
| |
| // We quantize the sizes to make it more difficult for an attacker to see precise |
| // impact of operations on memory. The values are used for performance tuning, |
| // and hence don't need to be as refined when the value is large, so we threshold |
| // at a list of exponentially separated buckets. |
| size_t quantizeMemorySize(size_t size) |
| { |
| const int numberOfBuckets = 100; |
| DEFINE_STATIC_LOCAL(Vector<size_t>, bucketSizeList, ()); |
| |
| if (bucketSizeList.isEmpty()) { |
| bucketSizeList.resize(numberOfBuckets); |
| |
| float sizeOfNextBucket = 10000000.0; // First bucket size is roughly 10M. |
| const float largestBucketSize = 4000000000.0; // Roughly 4GB. |
| // We scale with the Nth root of the ratio, so that we use all the bucktes. |
| const float scalingFactor = exp(log(largestBucketSize / sizeOfNextBucket) / numberOfBuckets); |
| |
| size_t nextPowerOfTen = static_cast<size_t>(pow(10, floor(log10(sizeOfNextBucket)) + 1) + 0.5); |
| size_t granularity = nextPowerOfTen / 1000; // We want 3 signficant digits. |
| |
| for (int i = 0; i < numberOfBuckets; ++i) { |
| size_t currentBucketSize = static_cast<size_t>(sizeOfNextBucket); |
| bucketSizeList[i] = currentBucketSize - (currentBucketSize % granularity); |
| |
| sizeOfNextBucket *= scalingFactor; |
| if (sizeOfNextBucket >= nextPowerOfTen) { |
| if (std::numeric_limits<size_t>::max() / 10 <= nextPowerOfTen) { |
| nextPowerOfTen = std::numeric_limits<size_t>::max(); |
| } else { |
| nextPowerOfTen *= 10; |
| granularity *= 10; |
| } |
| } |
| |
| // Watch out for overflow, if the range is too large for size_t. |
| if (i > 0 && bucketSizeList[i] < bucketSizeList[i - 1]) |
| bucketSizeList[i] = std::numeric_limits<size_t>::max(); |
| } |
| } |
| |
| for (int i = 0; i < numberOfBuckets; ++i) { |
| if (size <= bucketSizeList[i]) |
| return bucketSizeList[i]; |
| } |
| |
| return bucketSizeList[numberOfBuckets - 1]; |
| } |
| |
| MemoryInfo::MemoryInfo() |
| { |
| if (RuntimeEnabledFeatures::preciseMemoryInfoEnabled()) |
| getHeapSize(m_info); |
| else |
| HeapSizeCache::forCurrentThread().getCachedHeapSize(m_info); |
| } |
| |
| } // namespace blink |