Faster bugreports (1/n)

Adds a thread pool to dumpstate.

Bug: 136262402
Test: atest dumpstate_test
Change-Id: I83b48a696c60fafbd4cb0dd62d3acceaa43caabb
Merged-In: I83b48a696c60fafbd4cb0dd62d3acceaa43caabb
(cherry picked from commit 3432b93ad0e423a3bdd0b87fe3f3dabb9d572dae)

4 files changed, 411 insertions, 0 deletions

diff --git a/cmds/dumpstate/Android.bp b/cmds/dumpstate/Android.bp
index 40589345d2..1f055f3be7 100644
--- a/cmds/dumpstate/Android.bp
+++ b/cmds/dumpstate/Android.bp
@@ -105,6 +105,7 @@ cc_binary {
     name: "dumpstate",
     defaults: ["dumpstate_defaults"],
     srcs: [
+        "DumpPool.cpp",
         "dumpstate.cpp",
         "main.cpp",
     ],
@@ -132,6 +133,7 @@ cc_test {
     name: "dumpstate_test",
     defaults: ["dumpstate_defaults"],
     srcs: [
+        "DumpPool.cpp",
         "dumpstate.cpp",
         "tests/dumpstate_test.cpp",
     ],
@@ -148,6 +150,7 @@ cc_test {
     name: "dumpstate_smoke_test",
     defaults: ["dumpstate_defaults"],
     srcs: [
+        "DumpPool.cpp",
         "dumpstate.cpp",
         "tests/dumpstate_smoke_test.cpp",
     ],
diff --git a/cmds/dumpstate/DumpPool.cpp b/cmds/dumpstate/DumpPool.cpp
new file mode 100644
index 0000000000..7324ead7c6
--- /dev/null
+++ b/cmds/dumpstate/DumpPool.cpp
@@ -0,0 +1,171 @@
+/*
+ * Copyright (C) 2020 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_TAG "dumpstate"
+
+#include "DumpPool.h"
+
+#include <array>
+#include <thread>
+
+#include <log/log.h>
+
+#include "dumpstate.h"
+#include "DumpstateInternal.h"
+#include "DumpstateUtil.h"
+
+namespace android {
+namespace os {
+namespace dumpstate {
+
+const std::string DumpPool::PREFIX_TMPFILE_NAME = "dump-tmp.";
+
+DumpPool::DumpPool(const std::string& tmp_root) : tmp_root_(tmp_root), shutdown_(false) {
+    assert(!tmp_root.empty());
+    deleteTempFiles(tmp_root_);
+}
+
+DumpPool::~DumpPool() {
+    shutdown();
+}
+
+void DumpPool::start(int thread_counts) {
+    assert(thread_counts > 0);
+    assert(threads_.empty());
+    if (thread_counts > MAX_THREAD_COUNT) {
+        thread_counts = MAX_THREAD_COUNT;
+    }
+    MYLOGI("Start thread pool:%d", thread_counts);
+    shutdown_ = false;
+    for (int i = 0; i < thread_counts; i++) {
+        threads_.emplace_back(std::thread([=]() {
+            setThreadName(pthread_self(), i + 1);
+            loop();
+        }));
+    }
+}
+
+void DumpPool::shutdown() {
+    std::unique_lock lock(lock_);
+    if (shutdown_ || threads_.empty()) {
+        return;
+    }
+    while (!tasks_.empty()) tasks_.pop();
+    futures_map_.clear();
+
+    shutdown_ = true;
+    condition_variable_.notify_all();
+    lock.unlock();
+
+    for (auto& thread : threads_) {
+        thread.join();
+    }
+    threads_.clear();
+    deleteTempFiles(tmp_root_);
+    MYLOGI("shutdown thread pool");
+}
+
+void DumpPool::waitForTask(const std::string& task_name, const std::string& title,
+        int out_fd) {
+    DurationReporter duration_reporter("Wait for " + task_name, true);
+    auto iterator = futures_map_.find(task_name);
+    if (iterator == futures_map_.end()) {
+        MYLOGW("Task %s does not exist", task_name.c_str());
+        return;
+    }
+    Future future = iterator->second;
+    futures_map_.erase(iterator);
+
+    std::string result = future.get();
+    if (result.empty()) {
+        return;
+    }
+    DumpFileToFd(out_fd, title, result);
+    if (unlink(result.c_str())) {
+        MYLOGE("Failed to unlink (%s): %s\n", result.c_str(), strerror(errno));
+    }
+}
+
+std::unique_ptr<DumpPool::TmpFile> DumpPool::createTempFile() {
+    auto tmp_file_ptr = std::make_unique<TmpFile>();
+    std::string file_name_format = "%s/" + PREFIX_TMPFILE_NAME + "XXXXXX";
+    snprintf(tmp_file_ptr->path, sizeof(tmp_file_ptr->path), file_name_format.c_str(),
+             tmp_root_.c_str());
+    tmp_file_ptr->fd.reset(TEMP_FAILURE_RETRY(
+            mkostemp(tmp_file_ptr->path, O_CLOEXEC)));
+    if (tmp_file_ptr->fd.get() == -1) {
+        MYLOGE("open(%s, %s)\n", tmp_file_ptr->path, strerror(errno));
+        tmp_file_ptr = nullptr;
+        return tmp_file_ptr;
+    }
+    return tmp_file_ptr;
+}
+
+void DumpPool::deleteTempFiles(const std::string& folder) {
+    std::unique_ptr<DIR, decltype(&closedir)> dir_ptr(opendir(folder.c_str()),
+            &closedir);
+    if (!dir_ptr) {
+        MYLOGE("Failed to opendir (%s): %s\n", folder.c_str(), strerror(errno));
+        return;
+    }
+    int dir_fd = dirfd(dir_ptr.get());
+    if (dir_fd < 0) {
+        MYLOGE("Failed to get fd of dir (%s): %s\n", folder.c_str(),
+               strerror(errno));
+        return;
+    }
+
+    struct dirent* de;
+    while ((de = readdir(dir_ptr.get()))) {
+        if (de->d_type != DT_REG) {
+            continue;
+        }
+        std::string file_name(de->d_name);
+        if (file_name.find(PREFIX_TMPFILE_NAME) != 0) {
+            continue;
+        }
+        if (unlinkat(dir_fd, file_name.c_str(), 0)) {
+            MYLOGE("Failed to unlink (%s): %s\n", file_name.c_str(),
+                   strerror(errno));
+        }
+    }
+}
+
+void DumpPool::setThreadName(const pthread_t thread, int id) {
+    std::array<char, 15> name;
+    snprintf(name.data(), name.size(), "dumpstate_%d", id);
+    pthread_setname_np(thread, name.data());
+}
+
+void DumpPool::loop() {
+    std::unique_lock lock(lock_);
+    while (!shutdown_) {
+        if (tasks_.empty()) {
+            condition_variable_.wait(lock);
+            continue;
+        } else {
+            std::packaged_task<std::string()> task = std::move(tasks_.front());
+            tasks_.pop();
+            lock.unlock();
+            std::invoke(task);
+            lock.lock();
+        }
+    }
+}
+
+}  // namespace dumpstate
+}  // namespace os
+}  // namespace android
diff --git a/cmds/dumpstate/DumpPool.h b/cmds/dumpstate/DumpPool.h
new file mode 100644
index 0000000000..266d519b6d
--- /dev/null
+++ b/cmds/dumpstate/DumpPool.h
@@ -0,0 +1,161 @@
+/*
+ * Copyright (C) 2020 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.
+ */
+
+#ifndef FRAMEWORK_NATIVE_CMD_DUMPPOOL_H_
+#define FRAMEWORK_NATIVE_CMD_DUMPPOOL_H_
+
+#include <future>
+#include <map>
+#include <queue>
+#include <string>
+
+#include <android-base/file.h>
+#include <android-base/macros.h>
+
+namespace android {
+namespace os {
+namespace dumpstate {
+
+/*
+ * A thread pool with the fixed number of threads to execute multiple dump tasks
+ * simultaneously for the dumpstate. The dump task is a callable function
+ * included a file descriptor as a parameter, and the task could dump results to
+ * that fd. For example:
+ *
+ * void DumpXXXX(int out_fd) {
+ *     dprintf(out_fd, "Dump result to out_fd ...");
+ * }
+ * ...
+ * DumpPool pool(tmp_root);
+ * pool.enqueueTask("TaskName", &DumpXXXX, std::placeholders::_1);
+ * ...
+ * pool.waitForTask("TaskName");
+ *
+ * DumpXXXX is a callable function included a out_fd parameter. Using the
+ * enqueueTask method in DumpPool to enqueue the task to the pool. The
+ * std::placeholders::_1 is placeholder for DumpPool to pass a fd argument.
+ */
+class DumpPool {
+  public:
+    /*
+     * Creates a thread pool.
+     *
+     * |tmp_root| A path to a temporary folder for threads to create temporary
+     * files.
+     */
+    explicit DumpPool(const std::string& tmp_root);
+    ~DumpPool();
+
+    /*
+     * Starts the threads in the pool.
+     *
+     * |thread_counts| the number of threads to start.
+     */
+    void start(int thread_counts = MAX_THREAD_COUNT);
+
+    /*
+     * Requests to shutdown the pool and waits until all threads exit the loop.
+     */
+    void shutdown();
+
+    /*
+     * Adds a task with a task name into the queue of the thread pool.
+     *
+     * |task_name| The name of the task.
+     * |f| Callable function to execute the task. This function must
+     *     include a parameter of file descriptor to output dump result.
+     * |args| A list of arguments.
+     */
+    template<class F, class... Args> void enqueueTask(const std::string& task_name,
+            F&& f, Args&&... args) {
+        auto func = std::bind(std::forward<F>(f), std::forward<Args>(args)...);
+        futures_map_[task_name] = post(func);
+        if (threads_.empty()) {
+            start();
+        }
+    }
+
+    /*
+     * Waits until the task is finished. Dumps the task results to the STDOUT_FILENO.
+     */
+    void waitForTask(const std::string& task_name) {
+        waitForTask(task_name, "", STDOUT_FILENO);
+    }
+
+    /*
+     * Waits until the task is finished. Dumps the task results to the specified
+     * out_fd.
+     *
+     * |task_name| The name of the task.
+     * |title| Dump title string to the out_fd, an empty string for nothing.
+     * |out_fd| The target file to dump the result from the task.
+     */
+    void waitForTask(const std::string& task_name, const std::string& title, int out_fd);
+
+    static const std::string PREFIX_TMPFILE_NAME;
+
+  private:
+    using Task = std::packaged_task<std::string()>;
+    using Future = std::shared_future<std::string>;
+
+    template<class T> Future post(T dump_func) {
+        Task packaged_task([=]() {
+            std::unique_ptr<TmpFile> tmp_file_ptr = createTempFile();
+            if (!tmp_file_ptr) {
+                return std::string("");
+            }
+            std::invoke(dump_func, tmp_file_ptr->fd.get());
+            fsync(tmp_file_ptr->fd.get());
+            return std::string(tmp_file_ptr->path);
+        });
+        std::unique_lock lock(lock_);
+        auto future = packaged_task.get_future().share();
+        tasks_.push(std::move(packaged_task));
+        condition_variable_.notify_one();
+        return future;
+    }
+
+    typedef struct {
+      android::base::unique_fd fd;
+      char path[1024];
+    } TmpFile;
+
+    std::unique_ptr<TmpFile> createTempFile();
+    void deleteTempFiles(const std::string& folder);
+    void setThreadName(const pthread_t thread, int id);
+    void loop();
+
+  private:
+    static const int MAX_THREAD_COUNT = 4;
+
+    /* A path to a temporary folder for threads to create temporary files. */
+    std::string tmp_root_;
+    bool shutdown_;
+    std::mutex lock_;  // A lock for the tasks_.
+    std::condition_variable condition_variable_;
+
+    std::vector<std::thread> threads_;
+    std::queue<Task> tasks_;
+    std::map<std::string, Future> futures_map_;
+
+    DISALLOW_COPY_AND_ASSIGN(DumpPool);
+};
+
+}  // namespace dumpstate
+}  // namespace os
+}  // namespace android
+
+#endif //FRAMEWORK_NATIVE_CMD_DUMPPOOL_H_
diff --git a/cmds/dumpstate/tests/dumpstate_test.cpp b/cmds/dumpstate/tests/dumpstate_test.cpp
index c7df1bb6a3..d0a48266f2 100644
--- a/cmds/dumpstate/tests/dumpstate_test.cpp
+++ b/cmds/dumpstate/tests/dumpstate_test.cpp
@@ -21,6 +21,7 @@
 #include "DumpstateService.h"
 #include "android/os/BnDumpstate.h"
 #include "dumpstate.h"
+#include "DumpPool.h"
 
 #include <gmock/gmock.h>
 #include <gtest/gtest.h>
@@ -46,6 +47,7 @@ namespace dumpstate {
 
 using ::android::hardware::dumpstate::V1_1::DumpstateMode;
 using ::testing::EndsWith;
+using ::testing::Eq;
 using ::testing::HasSubstr;
 using ::testing::IsEmpty;
 using ::testing::IsNull;
@@ -1618,6 +1620,80 @@ TEST_F(DumpstateUtilTest, DumpFileOnDryRun) {
     EXPECT_THAT(out, EndsWith("skipped on dry run\n"));
 }
 
+class DumpPoolTest : public DumpstateBaseTest {
+  public:
+    void SetUp() {
+        DumpstateBaseTest::SetUp();
+        CreateOutputFile();
+    }
+
+    void CreateOutputFile() {
+        out_path_ = kTestDataPath + "out.txt";
+        out_fd_.reset(TEMP_FAILURE_RETRY(open(out_path_.c_str(),
+                O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC | O_NOFOLLOW,
+                S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH)));
+        ASSERT_GE(out_fd_.get(), 0) << "could not create FD for path "
+                << out_path_;
+    }
+
+    int getTempFileCounts(const std::string& folder) {
+        int count = 0;
+        std::unique_ptr<DIR, decltype(&closedir)> dir_ptr(opendir(folder.c_str()),
+                &closedir);
+        if (!dir_ptr) {
+            return -1;
+        }
+        int dir_fd = dirfd(dir_ptr.get());
+        if (dir_fd < 0) {
+            return -1;
+        }
+
+        struct dirent* de;
+        while ((de = readdir(dir_ptr.get()))) {
+            if (de->d_type != DT_REG) {
+                continue;
+            }
+            std::string file_name(de->d_name);
+            if (file_name.find(DumpPool::PREFIX_TMPFILE_NAME) != 0) {
+                continue;
+            }
+            count++;
+        }
+        return count;
+    }
+
+    android::base::unique_fd out_fd_;
+    std::string out_path_;
+};
+
+TEST_F(DumpPoolTest, EnqueueTask) {
+    DumpPool pool(kTestDataPath);
+    auto dump_func_1 = [](int out_fd) {
+        dprintf(out_fd, "A");
+    };
+    auto dump_func_2 = [](int out_fd) {
+        dprintf(out_fd, "B");
+        sleep(1);
+    };
+    auto dump_func_3 = [](int out_fd) {
+        dprintf(out_fd, "C");
+    };
+    pool.enqueueTask(/* task_name = */"1", dump_func_1, std::placeholders::_1);
+    pool.enqueueTask(/* task_name = */"2", dump_func_2, std::placeholders::_1);
+    pool.enqueueTask(/* task_name = */"3", dump_func_3, std::placeholders::_1);
+
+    pool.waitForTask("1", "", out_fd_.get());
+    pool.waitForTask("2", "", out_fd_.get());
+    pool.waitForTask("3", "", out_fd_.get());
+
+    std::string result;
+    ReadFileToString(out_path_, &result);
+    EXPECT_THAT(result, StrEq("A\nB\nC\n"));
+    EXPECT_THAT(getTempFileCounts(kTestDataPath), Eq(0));
+    pool.shutdown();
+}
+
+
 }  // namespace dumpstate
 }  // namespace os
 }  // namespace android