forked from mirrors/gecko-dev
126bd9e1a4
This patch was generated automatically by the "modeline.py" script, available here: https://github.com/amccreight/moz-source-tools/blob/master/modeline.py For every file that is modified in this patch, the changes are as follows: (1) The patch changes the file to use the exact C++ mode lines from the Mozilla coding style guide, available here: https://developer.mozilla.org/en-US/docs/Mozilla/Developer_guide/Coding_Style#Mode_Line (2) The patch deletes any blank lines between the mode line & the MPL boilerplate comment. (3) If the file previously had the mode lines and MPL boilerplate in a single contiguous C++ comment, then the patch splits them into separate C++ comments, to match the boilerplate in the coding style. MozReview-Commit-ID: 77D61xpSmIl --HG-- extra : rebase_source : c6162fa3cf539a07177a19838324bf368faa162b
102 lines
3.4 KiB
C++
102 lines
3.4 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#include "BufferCache.h"
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#include "MLGDevice.h"
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#include "ShaderDefinitionsMLGPU.h"
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#include "mozilla/MathAlgorithms.h"
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namespace mozilla {
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namespace layers {
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using namespace mlg;
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BufferCache::BufferCache(MLGDevice* aDevice)
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: mDevice(aDevice),
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mFirstSizeClass(CeilingLog2(kConstantBufferElementSize)),
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mFrameNumber(0),
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mNextSizeClassToShrink(0)
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{
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// Create a cache of buffers for each size class, where each size class is a
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// power of 2 between the minimum and maximum size of a constant buffer.
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size_t maxBindSize = mDevice->GetMaxConstantBufferBindSize();
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MOZ_ASSERT(IsPowerOfTwo(maxBindSize));
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size_t lastSizeClass = CeilingLog2(maxBindSize);
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MOZ_ASSERT(lastSizeClass >= mFirstSizeClass);
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mCaches.resize(lastSizeClass - mFirstSizeClass + 1);
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}
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BufferCache::~BufferCache()
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{
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}
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RefPtr<MLGBuffer>
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BufferCache::GetOrCreateBuffer(size_t aBytes)
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{
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size_t sizeClass = CeilingLog2(aBytes);
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size_t sizeClassIndex = sizeClass - mFirstSizeClass;
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if (sizeClassIndex >= mCaches.size()) {
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return mDevice->CreateBuffer(MLGBufferType::Constant, aBytes, MLGUsage::Dynamic, nullptr);
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}
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CachePool& pool = mCaches[sizeClassIndex];
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// See if we've cached a buffer that wasn't used in the past 2 frames. A buffer
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// used this frame could have already been mapped and written to, and a buffer
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// used the previous frame might still be in-use by the GPU. While the latter
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// case is okay, it causes aliasing in the driver. Since content is double
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// buffered we do not let the compositor get more than 1 frames ahead, and a
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// count of 2 frames should ensure the buffer is unused.
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if (!pool.empty() && mFrameNumber >= pool.front().mLastUsedFrame + 2) {
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RefPtr<MLGBuffer> buffer = pool.front().mBuffer;
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pool.pop_front();
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pool.push_back(CacheEntry(mFrameNumber, buffer));
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MOZ_RELEASE_ASSERT(buffer->GetSize() >= aBytes);
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return buffer;
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}
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// Allocate a new buffer and cache it.
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size_t bytes = (size_t(1) << sizeClass);
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MOZ_ASSERT(bytes >= aBytes);
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RefPtr<MLGBuffer> buffer =
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mDevice->CreateBuffer(MLGBufferType::Constant, bytes, MLGUsage::Dynamic, nullptr);
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if (!buffer) {
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return nullptr;
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}
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pool.push_back(CacheEntry(mFrameNumber, buffer));
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return buffer;
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}
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void
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BufferCache::EndFrame()
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{
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// Consider a buffer dead after ~5 seconds assuming 60 fps.
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static size_t kMaxUnusedFrameCount = 60 * 5;
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// At the end of each frame we pick one size class and see if it has any
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// buffers that haven't been used for many frames. If so we clear them.
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// The next frame we'll search the next size class. (This is just to spread
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// work over more than one frame.)
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CachePool& pool = mCaches[mNextSizeClassToShrink];
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while (!pool.empty()) {
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// Since the deque is sorted oldest-to-newest, front-to-back, we can stop
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// searching as soon as a buffer is active.
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if (mFrameNumber - pool.front().mLastUsedFrame < kMaxUnusedFrameCount) {
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break;
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}
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pool.pop_front();
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}
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mNextSizeClassToShrink = (mNextSizeClassToShrink + 1) % mCaches.size();
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mFrameNumber++;
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}
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} // namespace layers
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} // namespace mozilla
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