-// RPC stubs for clients to talk to lock_server
+// RPC stubs for clients to talk to lock_server, and cache the locks.
#include "lock_client.h"
-#include "rpc.h"
#include <arpa/inet.h>
-#include <sstream>
-#include <iostream>
-#include <stdio.h>
-
-lock_client::lock_client(std::string dst)
-{
- sockaddr_in dstsock;
- make_sockaddr(dst.c_str(), &dstsock);
- cl = new rpcc(dstsock);
- if (cl->bind() < 0) {
- printf("lock_client: call bind\n");
+void lock_state::wait(lock & mutex_lock) {
+ auto self = std::this_thread::get_id();
+ c[self].wait(mutex_lock);
+ c.erase(self);
+}
+
+void lock_state::signal() {
+ // signal anyone
+ if (c.begin() != c.end())
+ c.begin()->second.notify_one();
+}
+
+void lock_state::signal(thread::id who) {
+ if (c.count(who))
+ c[who].notify_one();
+}
+
+typedef map<lock_protocol::lockid_t, lock_state> lock_map;
+
+unsigned int lock_client::last_port = 0;
+
+lock_state & lock_client::get_lock_state(lock_protocol::lockid_t lid) {
+ lock sl(lock_table_lock);
+ return lock_table[lid]; // creates the lock if it doesn't already exist
+}
+
+lock_client::lock_client(string xdst, class lock_release_user *_lu) : lu(_lu), next_xid(0) {
+ cl = new rpcc(xdst);
+ if (cl->bind() < 0)
+ LOG("lock_client: call bind");
+
+ srandom((uint32_t)time(NULL)^last_port);
+ rlock_port = ((random()%32000) | (0x1 << 10));
+ id = "127.0.0.1:" + to_string(rlock_port);
+ last_port = rlock_port;
+ rpcs *rlsrpc = new rpcs(rlock_port);
+ rlsrpc->reg(rlock_protocol::revoke, &lock_client::revoke_handler, this);
+ rlsrpc->reg(rlock_protocol::retry, &lock_client::retry_handler, this);
+ rsmc = new rsm_client(xdst);
+ releaser_thread = thread(&lock_client::releaser, this);
+}
+
+void lock_client::releaser() [[noreturn]] {
+ while (1) {
+ lock_protocol::lockid_t lid;
+ release_fifo.deq(&lid);
+ LOG("Releaser: " << lid);
+
+ lock_state &st = get_lock_state(lid);
+ lock sl(st.m);
+ VERIFY(st.state == lock_state::locked && st.held_by == releaser_thread.get_id());
+ st.state = lock_state::releasing;
+ {
+ sl.unlock();
+ int r;
+ rsmc->call(lock_protocol::release, r, lid, id, st.xid);
+ if (lu)
+ lu->dorelease(lid);
+ sl.lock();
+ }
+ st.state = lock_state::none;
+ LOG("Lock " << lid << ": none");
+ st.signal();
}
}
-int
-lock_client::stat(lock_protocol::lockid_t lid)
-{
+int lock_client::stat(lock_protocol::lockid_t lid) {
+ VERIFY(0);
int r;
- lock_protocol::status ret = cl->call(lock_protocol::stat, cl->id(), lid, r);
+ auto ret = (lock_protocol::status)cl->call(lock_protocol::stat, r, cl->id(), lid);
VERIFY (ret == lock_protocol::OK);
return r;
}
-lock_protocol::status
-lock_client::acquire(lock_protocol::lockid_t lid)
-{
- int r;
- return cl->call(lock_protocol::acquire, cl->id(), lid, r);
+lock_protocol::status lock_client::acquire(lock_protocol::lockid_t lid) {
+ lock_state &st = get_lock_state(lid);
+ lock sl(st.m);
+ auto self = std::this_thread::get_id();
+
+ // check for reentrancy
+ VERIFY(st.state != lock_state::locked || st.held_by != self);
+ VERIFY(find(st.wanted_by.begin(), st.wanted_by.end(), self) == st.wanted_by.end());
+
+ st.wanted_by.push_back(self);
+
+ while (1) {
+ if (st.state != lock_state::free)
+ LOG("Lock " << lid << ": not free");
+
+ if (st.state == lock_state::none || st.state == lock_state::retrying) {
+ if (st.state == lock_state::none) {
+ lock l(xid_mutex);
+ st.xid = next_xid++;
+ }
+ st.state = lock_state::acquiring;
+ LOG("Lock " << lid << ": acquiring");
+ lock_protocol::status result;
+ {
+ sl.unlock();
+ int r;
+ result = (lock_protocol::status)rsmc->call(lock_protocol::acquire, r, lid, id, st.xid);
+ sl.lock();
+ }
+ LOG("acquire returned " << result);
+ if (result == lock_protocol::OK) {
+ st.state = lock_state::free;
+ LOG("Lock " << lid << ": free");
+ }
+ }
+
+ VERIFY(st.wanted_by.size() != 0);
+ if (st.state == lock_state::free) {
+ // is it for me?
+ auto front = st.wanted_by.front();
+ if (front == releaser_thread.get_id()) {
+ st.wanted_by.pop_front();
+ st.state = lock_state::locked;
+ st.held_by = releaser_thread.get_id();
+ LOG("Queuing " << lid << " for release");
+ release_fifo.enq(lid);
+ } else if (front == self) {
+ st.wanted_by.pop_front();
+ st.state = lock_state::locked;
+ st.held_by = self;
+ break;
+ } else {
+ st.signal(front);
+ }
+ }
+
+ LOG("waiting...");
+ st.wait(sl);
+ LOG("wait ended");
+ }
+
+ LOG("Lock " << lid << ": locked");
+ return lock_protocol::OK;
}
-lock_protocol::status
-lock_client::release(lock_protocol::lockid_t lid)
-{
- int r;
- return cl->call(lock_protocol::release, cl->id(), lid, r);
+lock_protocol::status lock_client::release(lock_protocol::lockid_t lid) {
+ lock_state &st = get_lock_state(lid);
+ lock sl(st.m);
+ auto self = std::this_thread::get_id();
+ VERIFY(st.state == lock_state::locked && st.held_by == self);
+ st.state = lock_state::free;
+ LOG("Lock " << lid << ": free");
+ if (st.wanted_by.size()) {
+ auto front = st.wanted_by.front();
+ if (front == releaser_thread.get_id()) {
+ st.state = lock_state::locked;
+ st.held_by = releaser_thread.get_id();
+ st.wanted_by.pop_front();
+ LOG("Queuing " << lid << " for release");
+ release_fifo.enq(lid);
+ } else
+ st.signal(front);
+ }
+ LOG("Finished signaling.");
+ return lock_protocol::OK;
+}
+
+rlock_protocol::status lock_client::revoke_handler(int &, lock_protocol::lockid_t lid, lock_protocol::xid_t xid) {
+ LOG("Revoke handler " << lid << " " << xid);
+ lock_state &st = get_lock_state(lid);
+ lock sl(st.m);
+
+ if (st.state == lock_state::releasing || st.state == lock_state::none)
+ return rlock_protocol::OK;
+
+ if (st.state == lock_state::free &&
+ (st.wanted_by.size() == 0 || st.wanted_by.front() == releaser_thread.get_id())) {
+ // gimme
+ st.state = lock_state::locked;
+ st.held_by = releaser_thread.get_id();
+ if (st.wanted_by.size())
+ st.wanted_by.pop_front();
+ release_fifo.enq(lid);
+ } else {
+ // get in line
+ st.wanted_by.push_back(releaser_thread.get_id());
+ }
+ return rlock_protocol::OK;
+}
+
+rlock_protocol::status lock_client::retry_handler(int &, lock_protocol::lockid_t lid, lock_protocol::xid_t) {
+ lock_state &st = get_lock_state(lid);
+ lock sl(st.m);
+ VERIFY(st.state == lock_state::acquiring);
+ st.state = lock_state::retrying;
+ LOG("Lock " << lid << ": none");
+ st.signal(); // only one thread needs to wake up
+ return rlock_protocol::OK;
}
t4_lock_client *t4_lock_client_new(const char *dst) {
}
t4_status t4_lock_client_release(t4_lock_client *client, t4_lockid_t lid) {
- return ((lock_client *)client)->acquire(lid);
+ return ((lock_client *)client)->release(lid);
}
t4_status t4_lock_client_stat(t4_lock_client *client, t4_lockid_t lid) {
return ((lock_client *)client)->stat(lid);
}
-
projects / invirt/third/libt4.git / blobdiff