X-Git-Url: http://xvm.mit.edu/gitweb/invirt/third/libt4.git/blobdiff_plain/5d99dbf06a14904944f5593c63705934bdfdcfb7..e0c49ff6ba44cf5b47ab91d58b67763f5a1c7a58:/paxos.cc?ds=sidebyside

diff --git a/paxos.cc b/paxos.cc
index b39fa5b..c7f2d1d 100644
--- a/paxos.cc
+++ b/paxos.cc
@@ -1,13 +1,17 @@
 #include "paxos.h"
-#include "handle.h"
+
+using namespace std::placeholders;
+
+paxos_change::~paxos_change() {}
 
 bool isamember(const node_t & m, const nodes_t & nodes) {
-    return find(nodes.begin(), nodes.end(), m) != nodes.end();
+    return std::find(nodes.begin(), nodes.end(), m) != nodes.end();
 }
 
 // check if l2 contains a majority of the elements of l1
-bool majority(const nodes_t &l1, const nodes_t &l2) {
-    auto overlap = (size_t)count_if(l1.begin(), l1.end(), bind(isamember, _1, l2));
+bool majority(const nodes_t & l1, const nodes_t & l2) {
+    auto overlap = (size_t)std::count_if(
+            l1.begin(), l1.end(), std::bind(isamember, _1, l2));
     return overlap >= (l1.size() >> 1) + 1;
 }
 
@@ -20,7 +24,7 @@ bool majority(const nodes_t &l1, const nodes_t &l2) {
 // paxos_commit to inform higher layers of the agreed value for this
 // instance.
 
-proposer_acceptor::proposer_acceptor(class paxos_change *_delegate,
+proposer_acceptor::proposer_acceptor(paxos_change *_delegate,
         bool _first, const node_t & _me, const value_t & _value)
     : delegate(_delegate), me (_me)
 {
@@ -39,20 +43,23 @@ proposer_acceptor::proposer_acceptor(class paxos_change *_delegate,
 bool proposer_acceptor::run(unsigned instance, const nodes_t & cur_nodes, const value_t & newv)
 {
     lock ml(proposer_mutex);
-    LOG("initiate paxos for " << cur_nodes << " w. i=" << instance << " v=\"" << newv << "\" stable=" << stable);
+    LOG << "initiate paxos for " << cur_nodes << " w. i=" << instance << " v=\"" << newv << "\" stable=" << stable;
     if (!stable) {  // already running proposer?
-        LOG("paxos proposer already running");
+        LOG << "paxos proposer already running";
         return false;
     }
     stable = false;
     bool r = false;
-    proposal.n = max(promise.n, proposal.n) + 1;
+    proposal.n = std::max(promise.n, proposal.n) + 1;
     nodes_t accepts;
-    value_t v = newv;
+    value_t v;
     if (prepare(instance, accepts, cur_nodes, v)) {
 
         if (majority(cur_nodes, accepts)) {
-            LOG("received a majority of prepare responses");
+            LOG << "received a majority of prepare responses";
+
+            if (!v.size())
+                v = newv;
 
             breakpoint1();
 
@@ -61,20 +68,20 @@ bool proposer_acceptor::run(unsigned instance, const nodes_t & cur_nodes, const
             accept(instance, accepts, nodes, v);
 
             if (majority(cur_nodes, accepts)) {
-                LOG("received a majority of accept responses");
+                LOG << "received a majority of accept responses";
 
                 breakpoint2();
 
                 decide(instance, accepts, v);
                 r = true;
             } else {
-                LOG("no majority of accept responses");
+                LOG << "no majority of accept responses";
             }
         } else {
-            LOG("no majority of prepare responses");
+            LOG << "no majority of prepare responses";
         }
     } else {
-        LOG("prepare is rejected " << stable);
+        LOG << "prepare is rejected " << stable;
     }
     stable = true;
     return r;
@@ -82,28 +89,27 @@ bool proposer_acceptor::run(unsigned instance, const nodes_t & cur_nodes, const
 
 bool proposer_acceptor::prepare(unsigned instance, nodes_t & accepts,
         const nodes_t & nodes, value_t & v) {
-    LOG("sending prepare messages (" << proposal.n << ", " << proposal.m << ", \"" << v << "\")");
+    LOG << "sending prepare messages (" << proposal.n << ", " << proposal.m << ", \"" << v << "\")";
     prepareres res;
     prop_t highest_n_a{0, ""};
     for (auto i : nodes) {
-        handle h(i);
-        rpcc *r = h.safebind();
-        if (!r)
+        auto cl = rpcc::bind_cached(i);
+        if (!cl)
             continue;
-        auto status = (paxos_protocol::status)r->call_timeout(
-                paxos_protocol::preparereq, rpcc::to(1000), res, me, instance, proposal);
+        int status = cl->call_timeout(paxos_protocol::preparereq, milliseconds(100),
+                res, me, instance, proposal);
         if (status == paxos_protocol::OK) {
-            if (res.oldinstance) {
-                LOG("commiting old instance!");
-                commit(instance, res.v_a);
+            LOG << "preparereq response type=" << res.type << " n_a=(" << res.n_a.n
+                << ", " << res.n_a.m << ") " << "v_a=\"" << res.v_a << "\"";
+            if (res.type == prepareres::oldinstance) {
+                LOG << "commiting old instance!";
+                lock ml(acceptor_mutex);
+                commit(instance, res.v_a, ml);
                 return false;
-            }
-            LOG("preparereq responded with oldinstance=" << res.oldinstance << " accept=" << res.accept << " n_a=(" << res.n_a.n << ", " << res.n_a.m << ") " <<
-                    "v_a=\"" << res.v_a << "\"");
-            if (res.accept) {
+            } else if (res.type == prepareres::accept) {
                 accepts.push_back(i);
                 if (res.n_a >= highest_n_a) {
-                    LOG("found a newer accepted proposal, \"" << res.v_a << "\", with number (" << res.n_a.n << ", " << res.n_a.m << ")");
+                    LOG << "found a newer accepted proposal, \"" << res.v_a << "\", with number (" << res.n_a.n << ", " << res.n_a.m << ")";
                     v = res.v_a;
                     highest_n_a = res.n_a;
                 }
@@ -115,52 +121,42 @@ bool proposer_acceptor::prepare(unsigned instance, nodes_t & accepts,
 
 void proposer_acceptor::accept(unsigned instance, nodes_t & accepts,
         const nodes_t & nodes, const value_t & v) {
+    bool accept = false;
     for (auto i : nodes) {
-        handle h(i);
-        rpcc *r = h.safebind();
-        if (!r)
-            continue;
-        bool accept = false;
-        int status = r->call_timeout(
-                paxos_protocol::acceptreq, rpcc::to(1000), accept, me, instance, proposal, v);
-        if (status == paxos_protocol::OK && accept)
-            accepts.push_back(i);
+        if (auto cl = rpcc::bind_cached(i)) {
+            int status = cl->call_timeout(paxos_protocol::acceptreq, milliseconds(100),
+                    accept, me, instance, proposal, v);
+            if (status == paxos_protocol::OK && accept)
+                accepts.push_back(i);
+        }
     }
 }
 
 void proposer_acceptor::decide(unsigned instance, const nodes_t & accepts, const value_t & v) {
-    for (auto i : accepts) {
-        handle h(i);
-        rpcc *r = h.safebind();
-        if (!r)
-            continue;
-        int res = 0;
-        r->call_timeout(paxos_protocol::decidereq, rpcc::to(1000), res, me, instance, v);
-    }
+    int res = 0;
+    for (auto i : accepts)
+        if (auto cl = rpcc::bind_cached(i))
+            cl->call_timeout(paxos_protocol::decidereq, milliseconds(100), res, me, instance, v);
 }
 
 paxos_protocol::status
 proposer_acceptor::preparereq(prepareres & r, const node_t &, unsigned instance, prop_t n) {
-    LOG("instance " << instance << " proposal (" << n.n << ", " << n.m << ")");
+    LOG << "instance " << instance << " proposal (" << n.n << ", " << n.m << ")";
     lock ml(acceptor_mutex);
-    r.oldinstance = false;
-    r.accept = false;
-    r.n_a = accepted;
-    r.v_a = accepted_value;
     if (instance <= instance_h) {
-        LOG("old instance " << instance << " has value " << values[instance]);
-        r.oldinstance = true;
-        r.v_a = values[instance];
+        LOG << "old instance " << instance << " has value " << values[instance];
+        r = prepareres{prepareres::oldinstance, accepted, values[instance]};
     } else if (n > promise) {
-        LOG("looks good to me");
+        LOG << "looks good to me";
         promise = n;
         l.logprop(promise);
-        r.accept = true;
+        r = prepareres{prepareres::accept, accepted, accepted_value};
     } else {
-        LOG("I totally rejected this request.  Ha.");
+        LOG << "I totally rejected this request.  Ha.";
+        r = prepareres{prepareres::reject, accepted, accepted_value};
     }
-    LOG("preparereq is responding with oldinstance=" << r.oldinstance << " accept=" << r.accept << " n_a=(" << r.n_a.n << ", " << r.n_a.m << ") " <<
-        "v_a=\"" << r.v_a << "\"");
+    LOG << "preparereq is responding with oldinstance=" << r.oldinstance << " accept=" << r.accept
+        << " n_a=(" << r.n_a.n << ", " << r.n_a.m << ") " << "v_a=\"" << r.v_a << "\"";
     return paxos_protocol::OK;
 }
 
@@ -168,26 +164,24 @@ paxos_protocol::status
 proposer_acceptor::acceptreq(bool & r, const node_t &, unsigned instance, prop_t n, const value_t & v) {
     lock ml(acceptor_mutex);
     r = false;
-    if (instance == instance_h + 1) {
-        if (n >= promise) {
-            accepted = n;
-            accepted_value = v;
-            l.logaccept(accepted, accepted_value);
-            r = true;
-        }
-        return paxos_protocol::OK;
-    } else {
+    if (instance != instance_h + 1)
         return paxos_protocol::ERR;
+    if (n >= promise) {
+        accepted = n;
+        accepted_value = v;
+        l.logaccept(accepted, accepted_value);
+        r = true;
     }
+    return paxos_protocol::OK;
 }
 
 paxos_protocol::status
 proposer_acceptor::decidereq(int &, const node_t &, unsigned instance, const value_t & v) {
     lock ml(acceptor_mutex);
-    LOG("decidereq for accepted instance " << instance << " (my instance " << instance_h << ") v=" << accepted_value);
+    LOG << "decidereq for accepted instance " << instance << " (my instance " << instance_h << ") v=" << accepted_value;
     if (instance == instance_h + 1) {
         VERIFY(accepted_value == v);
-        commit(instance, accepted_value, ml);
+        commit(instance, v, ml);
     } else if (instance <= instance_h) {
         // we are ahead; ignore.
     } else {
@@ -197,24 +191,21 @@ proposer_acceptor::decidereq(int &, const node_t &, unsigned instance, const val
     return paxos_protocol::OK;
 }
 
-void proposer_acceptor::commit(unsigned instance, const value_t & value) {
-    lock ml(acceptor_mutex);
-    commit(instance, value, ml);
-}
-
-void proposer_acceptor::commit(unsigned instance, const value_t & value, lock & pxs_mutex_lock) {
-    LOG("acceptor::commit: instance=" << instance << " has v=" << value);
+void proposer_acceptor::commit(unsigned instance, const value_t & value, lock & acceptor_mutex_lock) {
+    VERIFY(&value != &accepted_value); // eited by aliasing?
+    VERIFY(acceptor_mutex_lock);
+    LOG << "instance=" << instance << " has v=" << value;
     if (instance > instance_h) {
-        LOG("commit: highestacceptedinstance = " << instance);
+        LOG << "highestacceptedinstance = " << instance;
         values[instance] = value;
         l.loginstance(instance, value);
         instance_h = instance;
         accepted = promise = {0, me};
         accepted_value.clear();
         if (delegate) {
-            pxs_mutex_lock.unlock();
+            acceptor_mutex_lock.unlock();
             delegate->paxos_commit(instance, value);
-            pxs_mutex_lock.lock();
+            acceptor_mutex_lock.lock();
         }
     }
 }
@@ -222,24 +213,24 @@ void proposer_acceptor::commit(unsigned instance, const value_t & value, lock &
 // For testing purposes
 void proposer_acceptor::breakpoint1() {
     if (break1) {
-        LOG("Dying at breakpoint 1!");
+        LOG << "Dying at breakpoint 1!";
         exit(1);
     }
 }
 
 void proposer_acceptor::breakpoint2() {
     if (break2) {
-        LOG("Dying at breakpoint 2!");
+        LOG << "Dying at breakpoint 2!";
         exit(1);
     }
 }
 
 void proposer_acceptor::breakpoint(int b) {
     if (b == 3) {
-        LOG("Proposer: breakpoint 1");
+        LOG << "breakpoint 1";
         break1 = true;
     } else if (b == 4) {
-        LOG("Proposer: breakpoint 2");
+        LOG << "breakpoint 2";
         break2 = true;
     }
 }