Change slot generation for BufferState

BufferState layers now do slot generation with buffer death considered
appropriately.  When a buffer dies, the slot will be pushed onto a stack
of available slots to be reused at the next opportunity.  This should
mimic BufferQueue slot behavior and prevent Composer Resources from
growing too large.

Test: build, boot, manual
Bug: 129351223

Change-Id: Icef9592593cacb0b5c6b12f6679fc2c4dabdcd19

1 files changed, 202 insertions, 0 deletions

diff --git a/services/surfaceflinger/ClientCache.cpp b/services/surfaceflinger/ClientCache.cpp
new file mode 100644
index 0000000000..77f2f5765c
--- /dev/null
+++ b/services/surfaceflinger/ClientCache.cpp
@@ -0,0 +1,202 @@
+/*
+ * Copyright 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+//#define LOG_NDEBUG 0
+#undef LOG_TAG
+#define LOG_TAG "ClientCache"
+#define ATRACE_TAG ATRACE_TAG_GRAPHICS
+
+#include <cinttypes>
+
+#include "ClientCache.h"
+
+namespace android {
+
+ANDROID_SINGLETON_STATIC_INSTANCE(ClientCache);
+
+ClientCache::ClientCache() : mDeathRecipient(new CacheDeathRecipient) {}
+
+bool ClientCache::getBuffer(const client_cache_t& cacheId,
+                            ClientCacheBuffer** outClientCacheBuffer) {
+    auto& [processToken, id] = cacheId;
+    if (processToken == nullptr) {
+        ALOGE("failed to get buffer, invalid (nullptr) process token");
+        return false;
+    }
+    auto it = mBuffers.find(processToken);
+    if (it == mBuffers.end()) {
+        ALOGE("failed to get buffer, invalid process token");
+        return false;
+    }
+
+    auto& processBuffers = it->second;
+
+    auto bufItr = processBuffers.find(id);
+    if (bufItr == processBuffers.end()) {
+        ALOGE("failed to get buffer, invalid buffer id");
+        return false;
+    }
+
+    ClientCacheBuffer& buf = bufItr->second;
+    *outClientCacheBuffer = &buf;
+    return true;
+}
+
+void ClientCache::add(const client_cache_t& cacheId, const sp<GraphicBuffer>& buffer) {
+    auto& [processToken, id] = cacheId;
+    if (processToken == nullptr) {
+        ALOGE("failed to cache buffer: invalid process token");
+        return;
+    }
+
+    if (!buffer) {
+        ALOGE("failed to cache buffer: invalid buffer");
+        return;
+    }
+
+    std::lock_guard lock(mMutex);
+    sp<IBinder> token;
+
+    // If this is a new process token, set a death recipient. If the client process dies, we will
+    // get a callback through binderDied.
+    auto it = mBuffers.find(processToken);
+    if (it == mBuffers.end()) {
+        token = processToken.promote();
+        if (!token) {
+            ALOGE("failed to cache buffer: invalid token");
+            return;
+        }
+
+        status_t err = token->linkToDeath(mDeathRecipient);
+        if (err != NO_ERROR) {
+            ALOGE("failed to cache buffer: could not link to death");
+            return;
+        }
+        auto [itr, success] =
+                mBuffers.emplace(processToken, std::unordered_map<uint64_t, ClientCacheBuffer>());
+        LOG_ALWAYS_FATAL_IF(!success, "failed to insert new process into client cache");
+        it = itr;
+    }
+
+    auto& processBuffers = it->second;
+
+    if (processBuffers.size() > BUFFER_CACHE_MAX_SIZE) {
+        ALOGE("failed to cache buffer: cache is full");
+        return;
+    }
+
+    processBuffers[id].buffer = buffer;
+}
+
+void ClientCache::erase(const client_cache_t& cacheId) {
+    auto& [processToken, id] = cacheId;
+    std::vector<sp<ErasedRecipient>> pendingErase;
+    {
+        std::lock_guard lock(mMutex);
+        ClientCacheBuffer* buf = nullptr;
+        if (!getBuffer(cacheId, &buf)) {
+            ALOGE("failed to erase buffer, could not retrieve buffer");
+            return;
+        }
+
+        for (auto& recipient : buf->recipients) {
+            sp<ErasedRecipient> erasedRecipient = recipient.promote();
+            if (erasedRecipient) {
+                pendingErase.push_back(erasedRecipient);
+            }
+        }
+
+        mBuffers[processToken].erase(id);
+    }
+
+    for (auto& recipient : pendingErase) {
+        recipient->bufferErased(cacheId);
+    }
+}
+
+sp<GraphicBuffer> ClientCache::get(const client_cache_t& cacheId) {
+    std::lock_guard lock(mMutex);
+
+    ClientCacheBuffer* buf = nullptr;
+    if (!getBuffer(cacheId, &buf)) {
+        ALOGE("failed to get buffer, could not retrieve buffer");
+        return nullptr;
+    }
+
+    return buf->buffer;
+}
+
+void ClientCache::registerErasedRecipient(const client_cache_t& cacheId,
+                                          const wp<ErasedRecipient>& recipient) {
+    std::lock_guard lock(mMutex);
+
+    ClientCacheBuffer* buf = nullptr;
+    if (!getBuffer(cacheId, &buf)) {
+        ALOGE("failed to register erased recipient, could not retrieve buffer");
+        return;
+    }
+    buf->recipients.insert(recipient);
+}
+
+void ClientCache::unregisterErasedRecipient(const client_cache_t& cacheId,
+                                            const wp<ErasedRecipient>& recipient) {
+    std::lock_guard lock(mMutex);
+
+    ClientCacheBuffer* buf = nullptr;
+    if (!getBuffer(cacheId, &buf)) {
+        ALOGE("failed to unregister erased recipient");
+        return;
+    }
+
+    buf->recipients.erase(recipient);
+}
+
+void ClientCache::removeProcess(const wp<IBinder>& processToken) {
+    std::vector<std::pair<sp<ErasedRecipient>, client_cache_t>> pendingErase;
+    {
+        if (processToken == nullptr) {
+            ALOGE("failed to remove process, invalid (nullptr) process token");
+            return;
+        }
+        std::lock_guard lock(mMutex);
+        auto itr = mBuffers.find(processToken);
+        if (itr == mBuffers.end()) {
+            ALOGE("failed to remove process, could not find process");
+            return;
+        }
+
+        for (auto& [id, clientCacheBuffer] : itr->second) {
+            client_cache_t cacheId = {processToken, id};
+            for (auto& recipient : clientCacheBuffer.recipients) {
+                sp<ErasedRecipient> erasedRecipient = recipient.promote();
+                if (erasedRecipient) {
+                    pendingErase.emplace_back(erasedRecipient, cacheId);
+                }
+            }
+        }
+        mBuffers.erase(itr);
+    }
+
+    for (auto& [recipient, cacheId] : pendingErase) {
+        recipient->bufferErased(cacheId);
+    }
+}
+
+void ClientCache::CacheDeathRecipient::binderDied(const wp<IBinder>& who) {
+    ClientCache::getInstance().removeProcess(who);
+}
+
+}; // namespace android