/src/rt/rust_port.cpp

  1
  2#include "rust_port.h"
  3#include "rust_task.h"
  4
  5rust_port::rust_port(rust_task *task, size_t unit_sz)
  6    : ref_count(1), kernel(task->kernel), task(task),
  7      unit_sz(unit_sz), buffer(kernel, unit_sz) {
  8
  9    LOG(task, comm,
 10        "new rust_port(task=0x%" PRIxPTR ", unit_sz=%d) -> port=0x%"
 11        PRIxPTR, (uintptr_t)task, unit_sz, (uintptr_t)this);
 12
 13    id = kernel->register_port(this);
 14}
 15
 16rust_port::~rust_port() {
 17    LOG(task, comm, "~rust_port 0x%" PRIxPTR, (uintptr_t) this);
 18}
 19
 20void rust_port::ref() {
 21    scoped_lock with(ref_lock);
 22    ref_count++;
 23}
 24
 25void rust_port::deref() {
 26    scoped_lock with(ref_lock);
 27    ref_count--;
 28    if (!ref_count) {
 29        // The port owner is waiting for the port to be detached (if it
 30        // hasn't already been killed)
 31        scoped_lock with(task->lifecycle_lock);
 32        if (task->blocked_on(&detach_cond)) {
 33            task->wakeup_inner(&detach_cond);
 34        }
 35    }
 36}
 37
 38void rust_port::begin_detach(uintptr_t *yield) {
 39    *yield = false;
 40
 41    kernel->release_port_id(id);
 42
 43    scoped_lock with(ref_lock);
 44    ref_count--;
 45
 46    if (ref_count != 0) {
 47        task->block(&detach_cond, "waiting for port detach");
 48        *yield = true;
 49    }
 50}
 51
 52void rust_port::end_detach() {
 53    // Just take the lock to make sure that the thread that signaled
 54    // the detach_cond isn't still holding it
 55    scoped_lock with(ref_lock);
 56    assert(ref_count == 0);
 57}
 58
 59void rust_port::send(void *sptr) {
 60    bool did_rendezvous = false;
 61    {
 62        scoped_lock with(lock);
 63
 64        buffer.enqueue(sptr);
 65
 66        assert(!buffer.is_empty() &&
 67               "rust_chan::transmit with nothing to send.");
 68
 69        {
 70            scoped_lock with(task->lifecycle_lock);
 71            if (task->blocked_on(this)) {
 72                KLOG(kernel, comm, "dequeued in rendezvous_ptr");
 73                buffer.dequeue(task->rendezvous_ptr);
 74                task->rendezvous_ptr = 0;
 75                task->wakeup_inner(this);
 76                did_rendezvous = true;
 77            }
 78        }
 79    }
 80
 81    if (!did_rendezvous) {
 82        // If the task wasn't waiting specifically on this port,
 83        // it may be waiting on a group of ports
 84
 85        rust_port_selector *port_selector = task->get_port_selector();
 86        // The port selector will check if the task is blocked, not us.
 87        port_selector->msg_sent_on(this);
 88    }
 89}
 90
 91void rust_port::receive(void *dptr, uintptr_t *yield) {
 92    LOG(task, comm, "port: 0x%" PRIxPTR ", dptr: 0x%" PRIxPTR
 93        ", size: 0x%" PRIxPTR,
 94        (uintptr_t) this, (uintptr_t) dptr, unit_sz);
 95
 96    scoped_lock with(lock);
 97
 98    *yield = false;
 99
100    if (buffer.is_empty() == false) {
101        buffer.dequeue(dptr);
102        LOG(task, comm, "<=== read data ===");
103        return;
104    }
105    memset(dptr, 0, buffer.unit_sz);
106
107    // No data was buffered on any incoming channel, so block this task on
108    // the port. Remember the rendezvous location so that any sender task
109    // can write to it before waking up this task.
110
111    LOG(task, comm, "<=== waiting for rendezvous data ===");
112    task->rendezvous_ptr = (uintptr_t*) dptr;
113    task->block(this, "waiting for rendezvous data");
114
115    // Blocking the task might fail if the task has already been killed, but
116    // in the event of both failure and success the task needs to yield. On
117    // success, it yields and waits to be unblocked. On failure it yields and
118    // is then fails the task.
119
120    *yield = true;
121}
122
123size_t rust_port::size() {
124    scoped_lock with(lock);
125    return buffer.size();
126}
127
128void rust_port::log_state() {
129    LOG(task, comm,
130        "port size: %d",
131        buffer.size());
132}
133
134//
135// Local Variables:
136// mode: C++
137// fill-column: 78;
138// indent-tabs-mode: nil
139// c-basic-offset: 4
140// buffer-file-coding-system: utf-8-unix
141// compile-command: "make -k -C $RBUILD 2>&1 | sed -e 's/\\/x\\//x:\\//g'";
142// End:
143//