adb: fix NonblockingFdConnection's behavior with large writes.
Large opportunistic writes would perform a write without updating
writable_ or waking up the polling thread, which resulted in the worker
thread never polling with POLLOUT.
Test: adb_benchmark
Change-Id: Ifed3b97a4b647b539dcd2df858572fa7da9a22d0
diff --git a/adb/transport_fd.cpp b/adb/transport_fd.cpp
index ec61279..a93e68a 100644
--- a/adb/transport_fd.cpp
+++ b/adb/transport_fd.cpp
@@ -85,18 +85,9 @@
if (pfds[0].revents) {
if ((pfds[0].revents & POLLOUT)) {
std::lock_guard<std::mutex> lock(this->write_mutex_);
- WriteResult result = DispatchWrites();
- switch (result) {
- case WriteResult::Error:
- *error = "write failed";
- return;
-
- case WriteResult::Completed:
- writable_ = true;
- break;
-
- case WriteResult::TryAgain:
- break;
+ if (DispatchWrites() == WriteResult::Error) {
+ *error = "write failed";
+ return;
}
}
@@ -179,13 +170,14 @@
WriteResult DispatchWrites() REQUIRES(write_mutex_) {
CHECK(!write_buffer_.empty());
- if (!writable_) {
- return WriteResult::TryAgain;
- }
-
auto iovs = write_buffer_.iovecs();
ssize_t rc = adb_writev(fd_.get(), iovs.data(), iovs.size());
if (rc == -1) {
+ if (errno == EAGAIN || errno == EWOULDBLOCK) {
+ writable_ = false;
+ return WriteResult::TryAgain;
+ }
+
return WriteResult::Error;
} else if (rc == 0) {
errno = 0;
@@ -194,6 +186,7 @@
// TODO: Implement a more efficient drop_front?
write_buffer_.take_front(rc);
+ writable_ = write_buffer_.empty();
if (write_buffer_.empty()) {
return WriteResult::Completed;
}
@@ -211,7 +204,12 @@
if (!packet->payload.empty()) {
write_buffer_.append(std::make_unique<IOVector::block_type>(std::move(packet->payload)));
}
- return DispatchWrites() != WriteResult::Error;
+
+ WriteResult result = DispatchWrites();
+ if (result == WriteResult::TryAgain) {
+ WakeThread();
+ }
+ return result != WriteResult::Error;
}
std::thread thread_;