iscsi: Enable the sock fd group polling mechanism

This patch is used to implement the sock fd event group
polling mechanism if there are incoming data from network
(read event in SPDK iSCSI target side) , thus we can awake
many connections one time, and it can reduce the system call
overhead.

Change-Id: I76c26a89ef9365d7e1ccec616985e7435253896b
Signed-off-by: Ziye Yang <optimistyzy@gmail.com>
Reviewed-on: https://review.gerrithub.io/399796
Tested-by: SPDK Automated Test System <sys_sgsw@intel.com>
Reviewed-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>

lib/iscsi/conn.c

@@ -81,6 +81,8 @@ void spdk_iscsi_conn_full_feature_do_work(void *arg);
 
 static void spdk_iscsi_conn_full_feature_migrate(void *arg1, void *arg2);
 static void spdk_iscsi_conn_stop(struct spdk_iscsi_conn *conn);
+static void spdk_iscsi_conn_sock_cb(void *arg, struct spdk_sock_group *group,
+				    struct spdk_sock *sock);
 
 static struct spdk_iscsi_conn *
 allocate_conn(void)
@@ -170,6 +172,30 @@ int spdk_initialize_iscsi_conns(void)
 	return 0;
 }
 
+static void
+spdk_iscsi_poll_group_add_conn_sock(struct spdk_iscsi_conn *conn)
+{
+	struct spdk_iscsi_poll_group *poll_group = &g_spdk_iscsi.poll_group[spdk_env_get_current_core()];
+	int rc;
+
+	rc = spdk_sock_group_add_sock(poll_group->sock_group, conn->sock, spdk_iscsi_conn_sock_cb, conn);
+	if (rc < 0) {
+		SPDK_ERRLOG("Failed to add sock=%p of conn=%p\n", conn->sock, conn);
+	}
+}
+
+static void
+spdk_iscsi_poll_group_remove_conn_sock(struct spdk_iscsi_conn *conn)
+{
+	struct spdk_iscsi_poll_group *poll_group = &g_spdk_iscsi.poll_group[spdk_env_get_current_core()];
+	int rc;
+
+	rc = spdk_sock_group_remove_sock(poll_group->sock_group, conn->sock);
+	if (rc < 0) {
+		SPDK_ERRLOG("Failed to remove sock=%p of conn=%p\n", conn->sock, conn);
+	}
+}
+
 static void
 spdk_iscsi_poll_group_add_conn(struct spdk_iscsi_conn *conn,
 			       spdk_iscsi_conn_fn fn)
@@ -178,6 +204,7 @@ spdk_iscsi_poll_group_add_conn(struct spdk_iscsi_conn *conn,
 
 	conn->fn = fn;
 	STAILQ_INSERT_TAIL(&poll_group->connections, conn, link);
+	spdk_iscsi_poll_group_add_conn_sock(conn);
 }
 
 static void
@@ -500,6 +527,7 @@ void spdk_iscsi_conn_destruct(struct spdk_iscsi_conn *conn)
 	}
 
 	spdk_clear_all_transfer_task(conn, NULL);
+	spdk_iscsi_poll_group_remove_conn_sock(conn);
 	spdk_sock_close(&conn->sock);
 	spdk_poller_unregister(&conn->logout_timer);
 	spdk_poller_unregister(&conn->flush_poller);
@@ -1106,11 +1134,26 @@ spdk_iscsi_conn_handle_incoming_pdus(struct spdk_iscsi_conn *conn)
 	return i;
 }
 
+static void
+spdk_iscsi_conn_sock_cb(void *arg, struct spdk_sock_group *group, struct spdk_sock *sock)
+{
+	struct spdk_iscsi_conn *conn = arg;
+	int rc;
+
+	assert(conn != NULL);
+
+	/* Handle incoming PDUs */
+	rc = spdk_iscsi_conn_handle_incoming_pdus(conn);
+	if (rc < 0) {
+		conn->state = ISCSI_CONN_STATE_EXITING;
+		spdk_iscsi_conn_flush_pdus(conn);
+	}
+}
+
 static int
 spdk_iscsi_conn_execute(struct spdk_iscsi_conn *conn)
 {
 	int				rc = 0;
-	bool				conn_active = false;
 
 	if (conn->state == ISCSI_CONN_STATE_EXITED) {
 		return -1;
@@ -1126,22 +1169,8 @@ spdk_iscsi_conn_execute(struct spdk_iscsi_conn *conn)
 		goto conn_exit;
 	}
 
-	/* Handle incoming PDUs */
-	rc = spdk_iscsi_conn_handle_incoming_pdus(conn);
-	if (rc < 0) {
-		conn->state = ISCSI_CONN_STATE_EXITING;
-		spdk_iscsi_conn_flush_pdus(conn);
-		goto conn_exit;
-	} else if (rc > 0) {
-		conn_active = true;
-	}
-
 	spdk_iscsi_conn_handle_queued_datain_tasks(conn);
 
-	if (conn_active) {
-		return 1;
-	}
-
 conn_exit:
 	if (conn->state == ISCSI_CONN_STATE_EXITING) {
 		spdk_iscsi_conn_destruct(conn);
@@ -1210,6 +1239,7 @@ spdk_iscsi_conn_login_do_work(void *arg)
 			pthread_mutex_unlock(&target->mutex);
 		}
 
+		spdk_iscsi_poll_group_remove_conn_sock(conn);
 		spdk_iscsi_conn_stop(conn);
 
 		__sync_fetch_and_add(&g_num_connections[lcore], 1);

lib/iscsi/iscsi.h

@@ -260,6 +260,7 @@ struct spdk_iscsi_poll_group {
 	uint32_t					core;
 	struct spdk_poller				*poller;
 	STAILQ_HEAD(connections, spdk_iscsi_conn)	connections;
+	struct spdk_sock_group				*sock_group;
 };
 
 struct spdk_iscsi_globals {

lib/iscsi/iscsi_subsystem.c

@@ -35,6 +35,7 @@
 #include "spdk/stdinc.h"
 #include "spdk/env.h"
 #include "spdk/string.h"
+#include "spdk/sock.h"
 
 #include "iscsi/iscsi.h"
 #include "iscsi/init_grp.h"
@@ -835,6 +836,14 @@ spdk_iscsi_poll_group_poll(void *ctx)
 {
 	struct spdk_iscsi_poll_group *group = ctx;
 	struct spdk_iscsi_conn *conn, *tmp;
+	int rc;
+
+	if (!STAILQ_EMPTY(&group->connections)) {
+		rc = spdk_sock_group_poll(group->sock_group);
+		if (rc < 0) {
+			SPDK_ERRLOG("Failed to poll sock_group=%p\n", group->sock_group);
+		}
+	}
 
 	STAILQ_FOREACH_SAFE(conn, &group->connections, link, tmp) {
 		conn->fn(conn);
@@ -857,6 +866,9 @@ iscsi_create_poll_group(void *ctx)
 	assert(pg != NULL);
 
 	STAILQ_INIT(&pg->connections);
+	pg->sock_group = spdk_sock_group_create();
+	assert(pg->sock_group != NULL);
+
 	pg->poller = spdk_poller_register(spdk_iscsi_poll_group_poll, pg, 0);
 }
 
@@ -868,7 +880,9 @@ iscsi_unregister_poll_group(void *ctx)
 	pg = &g_spdk_iscsi.poll_group[spdk_env_get_current_core()];
 	assert(pg != NULL);
 	assert(pg->poller != NULL);
+	assert(pg->sock_group != NULL);
 
+	spdk_sock_group_close(&pg->sock_group);
 	spdk_poller_unregister(&pg->poller);
 }
 

test/unit/lib/iscsi/conn.c/conn_ut.c

@@ -139,6 +139,19 @@ spdk_sock_set_sendbuf(struct spdk_sock *sock, int sz)
 	return 0;
 }
 
+int
+spdk_sock_group_add_sock(struct spdk_sock_group *group, struct spdk_sock *sock,
+			 spdk_sock_cb cb_fn, void *cb_arg)
+{
+	return 0;
+}
+
+int
+spdk_sock_group_remove_sock(struct spdk_sock_group *group, struct spdk_sock *sock)
+{
+	return 0;
+}
+
 void
 spdk_scsi_task_put(struct spdk_scsi_task *task)
 {