Fixed ridiculous CPU usage

src/connections.c

@@ -32,36 +32,28 @@
 #include <responses.h>
 #include <connections.h>
 
-Connection *newConnection(int fd) {
-	Connection *ret = malloc(sizeof(Connection));
-	if (ret == NULL)
-		return NULL;
+int newConnection(int fd, Connection *ret) {
 	ret->fd = fd;
 	ret->progress = RECEIVE_REQUEST;
 
 	ret->currLineAlloc = 30;
 	ret->currLineLen = 0;
 	ret->currLine = malloc(ret->currLineAlloc);
-	if (ret->currLine == NULL) {
-		free(ret);
-		return NULL;
-	}
+	if (ret->currLine == NULL)
+		return 1;
 
 	ret->allocatedFields = 10;
 	ret->fields = malloc(sizeof(Field) * ret->allocatedFields);
 	if (ret->fields == NULL) {
 		free(ret->currLine);
-		free(ret);
-		return NULL;
+		return 1;
 	}
 
 	ret->path = NULL;
 	ret->body = NULL;
 	//pointers to things that are allocated within functions should be
 	//initialized to NULL so that free() doens't fail.
-
-	ret->next = NULL;
-	return ret;
+	return 0;
 }
 
 void resetConnection(Connection *conn) {
@@ -79,7 +71,6 @@ void freeConnection(Connection *conn) {
 	free(conn->path);
 	free(conn->fields);
 	free(conn->body);
-	free(conn);
 }
 
 static int processRequest(Connection *conn) {

src/include/connections.h

@@ -50,8 +50,6 @@ typedef struct Connection {
 	size_t bodylen;
 	size_t receivedBody;
 
-	struct Connection *next;
-
 	char *currLine;
 	//persistent
 	size_t currLineAlloc;
@@ -62,7 +60,7 @@ typedef struct Connection {
 //Ephemeral fields: Things which are freed and reallocated after each new
 //request, path, body
 
-Connection *newConnection(int fd);
+int newConnection(int fd, Connection *ret);
 //returns non-zero on error. creates a new connection bound to fd
 void resetConnection(Connection *conn);
 void freeConnection(Connection *conn);

src/include/runner.h

@@ -27,11 +27,10 @@ typedef struct {
 	int *pending;
 	//pending[thread id] = the number of connections being handled by that
 	//   thread
-	int *schedule;
+	int notify;
 	/*
-	 * schedule[0] = the thread that should take the next connection (-1 if
-	 *    there is no connection).
-	 * schedule[1] = the fd of the connection to be accepted
+	 * When this runner should accept a connection, notify will contain an
+	 * int ready to be read.
 	 */
 	int id;
 } RunnerArgs;

src/main.c

@@ -103,21 +103,20 @@ int main(int argc, char **argv) {
 	}
 
 	int *pending = calloc(processes - 1, sizeof(int));
-	int *schedule = malloc(2 * sizeof(int));
-	if (schedule == NULL)
-		exit(EXIT_FAILURE);
-	schedule[0] = -1;
+	int (*notify)[2] = malloc(sizeof(int[2]) * (processes - 1));
 	pthread_t *threads = malloc(sizeof(pthread_t) * (processes - 1));
 	if (threads == NULL)
 		exit(EXIT_FAILURE);
 
 	for (int i = 0; i < processes - 1; i++) {
+		if (pipe(notify[i]))
+			exit(EXIT_FAILURE);
 		RunnerArgs *args = malloc(sizeof(RunnerArgs));
 		if (args == NULL)
 			exit(EXIT_FAILURE);
 		args->site = site;
 		args->pending = pending;
-		args->schedule = schedule;
+		args->notify = notify[i][0];
 		args->id = i;
 		pthread_create(threads + i, NULL,
 		               (void*(*)(void*)) runServer, args);
@@ -126,24 +125,23 @@ int main(int argc, char **argv) {
 	for (;;) {
 		fsync(fd);
 		//TODO: Find out why this works
-		if (schedule[0] == -1) {
-			int newfd = accept(fd, (struct sockaddr *) &addr,
-			                       &addrlen);
-			if (newfd < 0)
-				exit(EXIT_FAILURE);
-			int flags = fcntl(newfd, F_GETFL);
-			if (fcntl(newfd, F_SETFL, flags | O_NONBLOCK))
-				exit(EXIT_FAILURE);
-			int lowestThread = 0;
-			int lowestCount = pending[0];
-			for (int i = 1; i < processes - 1; i++) {
-				if (pending[i] < lowestCount) {
-					lowestThread = i;
-					lowestCount = pending[i];
-				}
+		int newfd = accept(fd, (struct sockaddr *) &addr,
+		                       &addrlen);
+		if (newfd < 0)
+			exit(EXIT_FAILURE);
+		int flags = fcntl(newfd, F_GETFL);
+		if (fcntl(newfd, F_SETFL, flags | O_NONBLOCK))
+			exit(EXIT_FAILURE);
+		int lowestThread = 0;
+		int lowestCount = pending[0];
+		for (int i = 1; i < processes - 1; i++) {
+			if (pending[i] < lowestCount) {
+				lowestThread = i;
+				lowestCount = pending[i];
 			}
-			schedule[1] = newfd;
-			schedule[0] = lowestThread;
 		}
+		if (write(notify[lowestThread][1], &newfd, sizeof(newfd))
+		          < sizeof(newfd))
+			exit(EXIT_FAILURE);
 	}
 }

src/runner.c

@@ -22,6 +22,7 @@
 #include <string.h>
 #include <assert.h>
 
+#include <poll.h>
 #include <fcntl.h>
 #include <unistd.h>
 #include <sys/socket.h>
@@ -33,49 +34,56 @@
 void *runServer(RunnerArgs *args) {
 	Sitefile *site = args->site;
 	int *pending = args->pending;
-	int *schedule = args->schedule;
+	int notify = args->notify;
 	int id = args->id;
 
-	Connection *connections = NULL;
-	Connection *last = NULL;
-	//Connections are processed in a queue, which is really just a linked
-	//list where we add to the end and read from the beginning.
+	int allocConns = 100;
+	struct pollfd *fds = malloc(sizeof(struct pollfd) * allocConns);
+	Connection *connections = malloc(sizeof(Connection) * allocConns);
+	assert(fds != NULL);
+	assert(connections != NULL);
+	fds[0].fd = notify;
+	fds[0].events = POLLIN;
+	int connCount = 1;
+	//connections are 1 indexed, this is because fds[0] is the notify fd.
+
 	for (;;) {
-		if (schedule[0] == id) {
-			Connection *newconn = newConnection(schedule[1]);
-			assert(newconn != NULL);
+		poll(fds, connCount, -1);
 
-			if (last == NULL)
-				connections = newconn;
-			else
-				last->next = newconn;
-			last = newconn;
-			pending[id]++;
-			schedule[0] = -1;
-		}
-
-		Connection *prev = NULL;
-		Connection *iter = connections;
-		//I know of the Linus Thorvalds good taste code thing, it just
-		//gets very confusing very fast to think about pointers to
-		//pointers which have pointers.
-		while (iter != NULL) {
-			if (updateConnection(iter, site)) {
-				if (iter == last)
-					last = prev;
-				Connection *old = iter;
-				iter = iter->next;
-				freeConnection(old);
-				if (prev == NULL)
-					connections = iter;
-				else
-					prev->next = iter;
+		for (int i = 1; i < connCount; i++) {
+			if (updateConnection(connections + i, site)) {
+				connCount--;
+				memcpy(fds + i, fds + connCount,
+						sizeof(struct pollfd));
 				pending[id]--;
 			}
-			else {
-				prev = iter;
-				iter = iter->next;
+		}
+
+		if (fds[0].revents == POLLIN) {
+			if (connCount >= allocConns) {
+				allocConns *= 2;
+				struct pollfd *newfds = realloc(fds,
+					sizeof(struct pollfd) * allocConns);
+				if (newfds == NULL)
+					exit(EXIT_FAILURE);
+				fds = newfds;
+
+				Connection *newconns = realloc(connections,
+					sizeof(Connection) * allocConns);
+				if (newconns == NULL)
+					exit(EXIT_FAILURE);
+				connections = newconns;
 			}
+			int newfd;
+			if (read(notify, &newfd, sizeof(newfd)) < sizeof(newfd))
+				exit(EXIT_FAILURE);
+			fds[connCount].fd = newfd;
+			fds[connCount].events = POLLIN;
+
+			if (newConnection(newfd, connections + connCount))
+				exit(EXIT_FAILURE);
+			connCount++;
+			pending[id]++;
 		}
 	}
 	return NULL;