From 62575d9c4a26eb2fa0bd1a1dbf1580633a886dce Mon Sep 17 00:00:00 2001 From: Ben Blum Date: Thu, 12 Jul 2012 19:52:27 -0400 Subject: [PATCH] Reintroduce linked failure (rust_port locking) This reverts commit a10f52c5793b358a16e3e98db4b16c65ba8e254b. --- src/rt/rust_port.cpp | 28 +++++++++++++++------------- src/rt/rust_port_selector.cpp | 4 ++-- src/rt/rust_port_selector.h | 1 - src/rt/rust_task.cpp | 7 +++---- src/rt/rust_task.h | 6 ++++-- 5 files changed, 24 insertions(+), 22 deletions(-) diff --git a/src/rt/rust_port.cpp b/src/rt/rust_port.cpp index f1a40508acad3..919dadd4044eb 100644 --- a/src/rt/rust_port.cpp +++ b/src/rt/rust_port.cpp @@ -26,9 +26,11 @@ void rust_port::deref() { scoped_lock with(ref_lock); ref_count--; if (!ref_count) { + // The port owner is waiting for the port to be detached (if it + // hasn't already been killed) + scoped_lock with(task->lifecycle_lock); if (task->blocked_on(&detach_cond)) { - // The port owner is waiting for the port to be detached - task->wakeup(&detach_cond); + task->wakeup_inner(&detach_cond); } } } @@ -64,12 +66,15 @@ void rust_port::send(void *sptr) { assert(!buffer.is_empty() && "rust_chan::transmit with nothing to send."); - if (task->blocked_on(this)) { - KLOG(kernel, comm, "dequeued in rendezvous_ptr"); - buffer.dequeue(task->rendezvous_ptr); - task->rendezvous_ptr = 0; - task->wakeup(this); - did_rendezvous = true; + { + scoped_lock with(task->lifecycle_lock); + if (task->blocked_on(this)) { + KLOG(kernel, comm, "dequeued in rendezvous_ptr"); + buffer.dequeue(task->rendezvous_ptr); + task->rendezvous_ptr = 0; + task->wakeup_inner(this); + did_rendezvous = true; + } } } @@ -78,11 +83,8 @@ void rust_port::send(void *sptr) { // it may be waiting on a group of ports rust_port_selector *port_selector = task->get_port_selector(); - // This check is not definitive. The port selector will take a lock - // and check again whether the task is still blocked. - if (task->blocked_on(port_selector)) { - port_selector->msg_sent_on(this); - } + // The port selector will check if the task is blocked, not us. + port_selector->msg_sent_on(this); } } diff --git a/src/rt/rust_port_selector.cpp b/src/rt/rust_port_selector.cpp index 7b3b45788f73b..52f9e0c3a01fd 100644 --- a/src/rt/rust_port_selector.cpp +++ b/src/rt/rust_port_selector.cpp @@ -75,7 +75,7 @@ rust_port_selector::msg_sent_on(rust_port *port) { // Prevent two ports from trying to wake up the task // simultaneously - scoped_lock with(rendezvous_lock); + scoped_lock with(task->lifecycle_lock); if (task->blocked_on(this)) { for (size_t i = 0; i < n_ports; i++) { @@ -85,7 +85,7 @@ rust_port_selector::msg_sent_on(rust_port *port) { n_ports = 0; *task->rendezvous_ptr = (uintptr_t) port; task->rendezvous_ptr = NULL; - task->wakeup(this); + task->wakeup_inner(this); return; } } diff --git a/src/rt/rust_port_selector.h b/src/rt/rust_port_selector.h index 8dbf0c4032932..73f2a9e4a0c35 100644 --- a/src/rt/rust_port_selector.h +++ b/src/rt/rust_port_selector.h @@ -9,7 +9,6 @@ class rust_port_selector : public rust_cond { private: rust_port **ports; size_t n_ports; - lock_and_signal rendezvous_lock; public: rust_port_selector(); diff --git a/src/rt/rust_task.cpp b/src/rt/rust_task.cpp index fa05a71374556..3d88c05b3ff9b 100644 --- a/src/rt/rust_task.cpp +++ b/src/rt/rust_task.cpp @@ -243,7 +243,7 @@ rust_task::must_fail_from_being_killed_inner() { // Only run this on the rust stack void rust_task::yield(bool *killed) { - // FIXME (#2787): clean this up + // FIXME (#2875): clean this up if (must_fail_from_being_killed()) { { scoped_lock with(lifecycle_lock); @@ -346,12 +346,11 @@ void rust_task::assert_is_running() assert(state == task_state_running); } -// FIXME (#2851, #2787): This is only used by rust_port/rust_port selector, -// and is inherently racy. Get rid of it. +// FIXME (#2851) Remove this code when rust_port goes away? bool rust_task::blocked_on(rust_cond *on) { - scoped_lock with(lifecycle_lock); + lifecycle_lock.must_have_lock(); return cond == on; } diff --git a/src/rt/rust_task.h b/src/rt/rust_task.h index ba327822c3751..1d87a0ed56c1b 100644 --- a/src/rt/rust_task.h +++ b/src/rt/rust_task.h @@ -226,8 +226,11 @@ rust_task : public kernel_owned char const *file, size_t line); + friend class rust_port; + friend class rust_port_selector; bool block_inner(rust_cond *on, const char* name); void wakeup_inner(rust_cond *from); + bool blocked_on(rust_cond *cond); public: @@ -243,7 +246,6 @@ rust_task : public kernel_owned void *args); void start(); void assert_is_running(); - bool blocked_on(rust_cond *cond); // FIXME (#2851) Get rid of this. void *malloc(size_t sz, const char *tag, type_desc *td=0); void *realloc(void *data, size_t sz); @@ -435,7 +437,7 @@ rust_task::call_on_rust_stack(void *args, void *fn_ptr) { bool had_reentered_rust_stack = reentered_rust_stack; { - // FIXME (#2787) This must be racy. Figure it out. + // FIXME (#2875) This must be racy. Figure it out. scoped_lock with(lifecycle_lock); reentered_rust_stack = true; }