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adb: fix NonblockingFdConnection's behavior with large writes.

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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
This commit is contained in:
Josh Gao 2018-11-12 12:38:59 -08:00
parent 10d079a37b
commit bc4dbfafb1
1 changed files with 15 additions and 17 deletions
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32
adb/transport_fd.cpp
View file

@ -85,18 +85,9 @@ struct NonblockingFdConnection : public Connection {
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 @@ struct NonblockingFdConnection : public Connection {
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 @@ struct NonblockingFdConnection : public Connection {
// 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 @@ struct NonblockingFdConnection : public Connection {
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_;