RTR Server: Clean up clients array after every poll

This was a pending optimization from commit
23478fdff80e8ceeaeeaffc71880f950b3c71104.

In truth, this data structure should technically be a linked list.
But I'm not sure if sacrificing cache locality for faster removal is
worth the tradeoff.

diff --git a/src/rtr/rtr.c b/src/rtr/rtr.c
index 61560567fc7e4466d1496dd758ed80b237437bab..3058e1badfda5520cd93e099bae9041eaaafda1f 100644 (file)
--- a/src/rtr/rtr.c
+++ b/src/rtr/rtr.c
@@ -23,7 +23,6 @@ static volatile bool stop_server_thread;
 
 STATIC_ARRAY_LIST(server_arraylist, struct rtr_server);
 STATIC_ARRAY_LIST(client_arraylist, struct rtr_client);
-STATIC_ARRAY_LIST(pollfd_arraylist, struct pollfd);
 
 static struct server_arraylist servers;
 static struct client_arraylist clients;
@@ -570,7 +569,23 @@ print_poll_failure(struct pollfd *pfd, char const *what, char const *addr)
 }
 
 static void
-apply_pollfds(struct pollfd_arraylist *pollfds, unsigned int nclients)
+delete_dead_clients(void)
+{
+       unsigned int src;
+       unsigned int dst;
+
+       for (src = 0, dst = 0; src < clients.len; src++) {
+               if (clients.array[src].fd != -1) {
+                       clients.array[dst] = clients.array[src];
+                       dst++;
+               }
+       }
+
+       clients.len = dst;
+}
+
+static void
+apply_pollfds(struct pollfd *pollfds, unsigned int nclients)
 {
        struct pollfd *pfd;
        struct rtr_server *server;
@@ -578,7 +593,7 @@ apply_pollfds(struct pollfd_arraylist *pollfds, unsigned int nclients)
        unsigned int i;
 
        for (i = 0; i < servers.len; i++) {
-               pfd = &pollfds->array[i];
+               pfd = &pollfds[i];
                server = &servers.array[i];
 
                /* PR_DEBUG_MSG("pfd:%d server:%d", pfd->fd, server->fd); */
@@ -591,7 +606,7 @@ apply_pollfds(struct pollfd_arraylist *pollfds, unsigned int nclients)
        }
 
        for (i = 0; i < nclients; i++) {
-               pfd = &pollfds->array[servers.len + i];
+               pfd = &pollfds[servers.len + i];
                client = &clients.array[i];
 
                /* PR_DEBUG_MSG("pfd:%d client:%d", pfd->fd, client->fd); */
@@ -603,13 +618,13 @@ apply_pollfds(struct pollfd_arraylist *pollfds, unsigned int nclients)
                }
        }
 
-       /* TODO clean up client array */
+       delete_dead_clients();
 }
 
 static enum poll_verdict
 fddb_poll(void)
 {
-       struct pollfd_arraylist pollfds;
+       struct pollfd *pollfds; /* array */
 
        struct rtr_server *server;
        struct rtr_client *client;
@@ -619,22 +634,18 @@ fddb_poll(void)
        unsigned int i;
        int error;
 
-       pollfd_arraylist_init(&pollfds);
-
-       pollfds.len = servers.len + clients.len;
-       pollfds.capacity = pollfds.len;
-       pollfds.array = calloc(pollfds.len, sizeof(struct pollfd));
-       if (pollfds.array == NULL) {
+       pollfds = calloc(servers.len + clients.len, sizeof(struct pollfd));
+       if (pollfds == NULL) {
                pr_enomem();
                return PV_RETRY;
        }
 
        ARRAYLIST_FOREACH(&servers, server, i)
-               init_pollfd(&pollfds.array[i], server->fd);
+               init_pollfd(&pollfds[i], server->fd);
        ARRAYLIST_FOREACH(&clients, client, i)
-               init_pollfd(&pollfds.array[servers.len + i], client->fd);
+               init_pollfd(&pollfds[servers.len + i], client->fd);
 
-       error = poll(pollfds.array, pollfds.len, 1000);
+       error = poll(pollfds, servers.len + clients.len, 1000);
 
        if (stop_server_thread)
                goto stop;
@@ -665,7 +676,7 @@ fddb_poll(void)
        /* New connections */
        for (i = 0; i < servers.len; i++) {
                /* This fd is a listening socket. */
-               fd = &pollfds.array[i];
+               fd = &pollfds[i];
 
                /* PR_DEBUG_MSG("Server %u: fd:%d revents:%x",
                    i, fd->fd, fd->revents); */
@@ -690,7 +701,7 @@ fddb_poll(void)
        /* Client requests */
        for (i = 0; i < nclients; i++) {
                /* This fd is a client handler socket. */
-               fd = &pollfds.array[servers.len + i];
+               fd = &pollfds[servers.len + i];
 
                /* PR_DEBUG_MSG("Client %u: fd:%d revents:%x", i, fd->fd,
                    fd->revents); */
@@ -707,18 +718,18 @@ fddb_poll(void)
        }
 
        lock_mutex();
-       apply_pollfds(&pollfds, nclients);
+       apply_pollfds(pollfds, nclients);
        unlock_mutex();
        /* Fall through */
 
 success:
-       pollfd_arraylist_cleanup(&pollfds, NULL);
+       free(pollfds);
        return PV_CONTINUE;
 retry:
-       pollfd_arraylist_cleanup(&pollfds, NULL);
+       free(pollfds);
        return PV_RETRY;
 stop:
-       pollfd_arraylist_cleanup(&pollfds, NULL);
+       free(pollfds);
        return PV_STOP;
 }