adb: fdevent: move run queue to fdevent_context. (3f06c2ba) · Commits · e / os / android_system_core

adb/fdevent/fdevent.cpp

+26 −0

Original line number	Diff line number	Diff line
		@@ -49,6 +49,32 @@ std::string dump_fde(const fdevent* fde) {
		state.c_str());
		}

		void fdevent_context::Run(std::function<void()> fn) {
		{
		std::lock_guard<std::mutex> lock(run_queue_mutex_);
		run_queue_.push_back(std::move(fn));
		}

		Interrupt();
		}

		void fdevent_context::FlushRunQueue() {
		// We need to be careful around reentrancy here, since a function we call can queue up another
		// function.
		while (true) {
		std::function<void()> fn;
		{
		std::lock_guard<std::mutex> lock(this->run_queue_mutex_);
		if (this->run_queue_.empty()) {
		break;
		}
		fn = this->run_queue_.front();
		this->run_queue_.pop_front();
		}
		fn();
		}
		}

		static auto& g_ambient_fdevent_context =
		*new std::unique_ptr<fdevent_context>(new fdevent_context_poll());

adb/fdevent/fdevent.h

+18 −1

Original line number	Diff line number	Diff line
		@@ -21,10 +21,14 @@
		#include <stdint.h>

		#include <chrono>
		#include <deque>
		#include <functional>
		#include <mutex>
		#include <optional>
		#include <variant>

		#include <android-base/thread_annotations.h>

		#include "adb_unique_fd.h"

		// Events that may be observed
		@@ -48,6 +52,7 @@ struct fdevent;
		std::string dump_fde(const fdevent* fde);

		struct fdevent_context {
		public:
		virtual ~fdevent_context() = default;

		// Allocate and initialize a new fdevent object.
		@@ -68,17 +73,29 @@ struct fdevent_context {
		virtual void SetTimeout(fdevent* fde, std::optional<std::chrono::milliseconds> timeout) = 0;

		// Loop forever, handling events.
		// Implementations should call FlushRunQueue on every iteration.
		virtual void Loop() = 0;

		// Assert that the caller is running on the context's main thread.
		virtual void CheckMainThread() = 0;

		// Queue an operation to be run on the main thread.
		virtual void Run(std::function<void()> fn) = 0;
		void Run(std::function<void()> fn);

		// Test-only functionality:
		virtual void TerminateLoop() = 0;
		virtual size_t InstalledCount() = 0;

		protected:
		// Interrupt the run loop.
		virtual void Interrupt() = 0;

		// Run all pending functions enqueued via Run().
		void FlushRunQueue() EXCLUDES(run_queue_mutex_);

		private:
		std::mutex run_queue_mutex_;
		std::deque<std::function<void()>> run_queue_ GUARDED_BY(run_queue_mutex_);
		};

		struct fdevent {

adb/fdevent/fdevent_poll.cpp

+44 −79

Original line number	Diff line number	Diff line
		@@ -50,6 +50,35 @@
		#include "fdevent.h"
		#include "sysdeps/chrono.h"

		static void fdevent_interrupt(int fd, unsigned, void*) {
		char buf[BUFSIZ];
		ssize_t rc = TEMP_FAILURE_RETRY(adb_read(fd, buf, sizeof(buf)));
		if (rc == -1) {
		PLOG(FATAL) << "failed to read from fdevent interrupt fd";
		}
		}

		fdevent_context_poll::fdevent_context_poll() {
		int s[2];
		if (adb_socketpair(s) != 0) {
		PLOG(FATAL) << "failed to create fdevent interrupt socketpair";
		}

		if (!set_file_block_mode(s[0], false) \|\| !set_file_block_mode(s[1], false)) {
		PLOG(FATAL) << "failed to make fdevent interrupt socket nonblocking";
		}

		this->interrupt_fd_.reset(s[0]);
		fdevent* fde = this->Create(unique_fd(s[1]), fdevent_interrupt, nullptr);
		CHECK(fde != nullptr);
		this->Add(fde, FDE_READ);
		}

		fdevent_context_poll::~fdevent_context_poll() {
		main_thread_valid_ = false;
		this->Destroy(this->interrupt_fde_);
		}

		void fdevent_context_poll::CheckMainThread() {
		if (main_thread_valid_) {
		CHECK_EQ(main_thread_id_, android::base::GetThreadId());
		@@ -291,79 +320,6 @@ static void fdevent_call_fdfunc(fdevent* fde) {
		fde->func);
		}

		static void fdevent_run_flush(fdevent_context_poll* ctx) EXCLUDES(ctx->run_queue_mutex_) {
		// We need to be careful around reentrancy here, since a function we call can queue up another
		// function.
		while (true) {
		std::function<void()> fn;
		{
		std::lock_guard<std::mutex> lock(ctx->run_queue_mutex_);
		if (ctx->run_queue_.empty()) {
		break;
		}
		fn = ctx->run_queue_.front();
		ctx->run_queue_.pop_front();
		}
		fn();
		}
		}

		static void fdevent_run_func(int fd, unsigned ev, void* data) {
		CHECK_GE(fd, 0);
		CHECK(ev & FDE_READ);

		bool* run_needs_flush = static_cast<bool*>(data);
		char buf[1024];

		// Empty the fd.
		if (adb_read(fd, buf, sizeof(buf)) == -1) {
		PLOG(FATAL) << "failed to empty run queue notify fd";
		}

		// Mark that we need to flush, and then run it at the end of fdevent_loop.
		*run_needs_flush = true;
		}

		static void fdevent_run_setup(fdevent_context_poll* ctx) {
		{
		std::lock_guard<std::mutex> lock(ctx->run_queue_mutex_);
		CHECK(ctx->run_queue_notify_fd_.get() == -1);
		int s[2];
		if (adb_socketpair(s) != 0) {
		PLOG(FATAL) << "failed to create run queue notify socketpair";
		}

		if (!set_file_block_mode(s[0], false) \|\| !set_file_block_mode(s[1], false)) {
		PLOG(FATAL) << "failed to make run queue notify socket nonblocking";
		}

		ctx->run_queue_notify_fd_.reset(s[0]);
		fdevent* fde = ctx->Create(unique_fd(s[1]), fdevent_run_func, &ctx->run_needs_flush_);
		CHECK(fde != nullptr);
		ctx->Add(fde, FDE_READ);
		}

		fdevent_run_flush(ctx);
		}

		void fdevent_context_poll::Run(std::function<void()> fn) {
		std::lock_guard<std::mutex> lock(run_queue_mutex_);
		run_queue_.push_back(std::move(fn));

		// run_queue_notify_fd could still be -1 if we're called before fdevent has finished setting up.
		// In that case, rely on the setup code to flush the queue without a notification being needed.
		if (run_queue_notify_fd_ != -1) {
		int rc = adb_write(run_queue_notify_fd_.get(), "", 1);

		// It's possible that we get EAGAIN here, if lots of notifications came in while handling.
		if (rc == 0) {
		PLOG(FATAL) << "run queue notify fd was closed?";
		} else if (rc == -1 && errno != EAGAIN) {
		PLOG(FATAL) << "failed to write to run queue notify fd";
		}
		}
		}

		static void fdevent_check_spin(fdevent_context_poll* ctx, uint64_t cycle) {
		// Check to see if we're spinning because we forgot about an fdevent
		// by keeping track of how long fdevents have been continuously pending.
		@@ -424,7 +380,6 @@ static void fdevent_check_spin(fdevent_context_poll* ctx, uint64_t cycle) {
		void fdevent_context_poll::Loop() {
		this->main_thread_id_ = android::base::GetThreadId();
		this->main_thread_valid_ = true;
		fdevent_run_setup(this);

		uint64_t cycle = 0;
		while (true) {
		@@ -444,17 +399,27 @@ void fdevent_context_poll::Loop() {
		fdevent_call_fdfunc(fde);
		}

		if (run_needs_flush_) {
		fdevent_run_flush(this);
		run_needs_flush_ = false;
		}
		this->FlushRunQueue();
		}
		}

		void fdevent_context_poll::TerminateLoop() {
		terminate_loop_ = true;
		Interrupt();
		}

		size_t fdevent_context_poll::InstalledCount() {
		return poll_node_map_.size();
		// We always have an installed fde for interrupt.
		return poll_node_map_.size() - 1;
		}

		void fdevent_context_poll::Interrupt() {
		int rc = adb_write(this->interrupt_fd_, "", 1);

		// It's possible that we get EAGAIN here, if lots of notifications came in while handling.
		if (rc == 0) {
		PLOG(FATAL) << "fdevent interrupt fd was closed?";
		} else if (rc == -1 && errno != EAGAIN) {
		PLOG(FATAL) << "failed to write to fdevent interrupt fd";
		}
		}

adb/fdevent/fdevent_poll.h

+9 −8

Original line number	Diff line number	Diff line
		@@ -25,6 +25,7 @@

		#include <android-base/thread_annotations.h>

		#include "adb_unique_fd.h"
		#include "fdevent.h"

		struct PollNode {
		@@ -44,7 +45,8 @@ struct PollNode {
		};

		struct fdevent_context_poll : public fdevent_context {
		virtual ~fdevent_context_poll() = default;
		fdevent_context_poll();
		virtual ~fdevent_context_poll();

		virtual fdevent* Create(unique_fd fd, std::variant<fd_func, fd_func2> func, void* arg) final;
		virtual unique_fd Destroy(fdevent* fde) final;
		@@ -58,11 +60,13 @@ struct fdevent_context_poll : public fdevent_context {

		virtual void CheckMainThread() final;

		virtual void Run(std::function<void()> fn) final;

		virtual void TerminateLoop() final;
		virtual size_t InstalledCount() final;

		protected:
		virtual void Interrupt() final;

		public:
		// All operations to fdevent should happen only in the main thread.
		// That's why we don't need a lock for fdevent.
		std::unordered_map<int, PollNode> poll_node_map_;
		@@ -71,10 +75,7 @@ struct fdevent_context_poll : public fdevent_context {
		uint64_t main_thread_id_ = 0;
		uint64_t fdevent_id_ = 0;

		bool run_needs_flush_ = false;
		unique_fd run_queue_notify_fd_;
		std::mutex run_queue_mutex_;
		std::deque<std::function<void()>> run_queue_ GUARDED_BY(run_queue_mutex_);

		unique_fd interrupt_fd_;
		fdevent* interrupt_fde_ = nullptr;
		std::atomic<bool> terminate_loop_ = false;
		};

adb/fdevent/fdevent_test.h

+2 −2

Original line number	Diff line number	Diff line
		@@ -78,8 +78,8 @@ class FdeventTest : public ::testing::Test {
		}

		size_t GetAdditionalLocalSocketCount() {
		// dummy socket installed in PrepareThread() + fdevent_run_on_main_thread socket
		return 2;
		// dummy socket installed in PrepareThread()
		return 1;
		}

		void TerminateThread() {