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Fixed deadlock by removing channel flushing.

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This commit is contained in:
Michael Bebenita 2010-08-17 23:21:29 -07:00
parent 6e9f0f952d
commit 7ff39ea448
2 changed files with 20 additions and 32 deletions
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13
src/rt/rust_port.cpp
View file

@ -23,6 +23,12 @@ rust_port::~rust_port() {
while (chans.is_empty() == false) {
rust_chan *chan = chans.peek();
chan->disassociate();
if (chan->ref_count == 0) {
task->log(rust_log::COMM,
"chan: 0x%" PRIxPTR " is dormant, freeing", chan);
delete chan;
}
}
delete remote_channel;
@ -33,13 +39,6 @@ bool rust_port::receive(void *dptr) {
rust_chan *chan = chans[i];
if (chan->buffer.is_empty() == false) {
chan->buffer.dequeue(dptr);
if (chan->buffer.is_empty() && chan->task->blocked()) {
task->log(rust_log::COMM,
"chan: 0x%" PRIxPTR
" is flushing, wakeup task: 0x%" PRIxPTR,
chan, chan->task);
chan->task->wakeup(this);
}
task->log(rust_log::COMM, "<=== read data ===");
return true;
}

39
src/rt/rust_upcall.cpp
View file

@ -108,29 +108,7 @@ upcall_new_chan(rust_task *task, rust_port *port) {
extern "C" CDECL void
upcall_flush_chan(rust_task *task, rust_chan *chan) {
LOG_UPCALL_ENTRY(task);
rust_dom *dom = task->dom;
task->log(rust_log::UPCALL | rust_log::COMM,
"flush chan: 0x%" PRIxPTR, chan);
if (chan->buffer.is_empty()) {
return;
}
// We cannot flush if the target port was dropped.
if (chan->is_associated() == false) {
return;
}
A(dom, chan->is_associated(),
"Channel should be associated to a port.");
A(dom, chan->port->is_proxy() == false,
"Channels to remote ports should be flushed automatically.");
// Block on the port until this channel has been completely drained
// by the port.
task->block(chan->port);
task->yield(2);
// Nop.
}
/**
@ -149,8 +127,19 @@ extern "C" CDECL void upcall_del_chan(rust_task *task, rust_chan *chan) {
"Channel's ref count should be zero.");
if (chan->is_associated()) {
A(task->dom, chan->buffer.is_empty(),
"Channel's buffer should be empty.");
// We're trying to delete a channel that another task may be reading
// from. We have two options:
//
// 1. We can flush the channel by blocking in upcall_flush_chan()
// and resuming only when the channel is flushed. The problem
// here is that we can get ourselves in a deadlock if the parent
// task tries to join us.
//
// 2. We can leave the channel in a "dormnat" state by not freeing
// it and letting the receiver task delete it for us instead.
if (chan->buffer.is_empty() == false) {
return;
}
chan->disassociate();
}
delete chan;