iscsi: create a iSCSI poll group for each core

This patch adds a iSCSI poll group for each core,
thus we can poll a group of connections instead of one
by one on each core.

Change-Id: I9cd82c8c0f7f6e7b3ee34034339638199bfca5da
Signed-off-by: Ziye Yang <optimistyzy@gmail.com>
Reviewed-on: https://review.gerrithub.io/399565
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Tested-by: SPDK Automated Test System <sys_sgsw@intel.com>

lib/iscsi/conn.c

@@ -170,6 +170,24 @@ int spdk_initialize_iscsi_conns(void)
 	return 0;
 }
 
+static void
+spdk_iscsi_poll_group_add_conn(struct spdk_iscsi_conn *conn,
+			       spdk_iscsi_conn_fn fn)
+{
+	struct spdk_iscsi_poll_group *poll_group = &g_spdk_iscsi.poll_group[spdk_env_get_current_core()];
+
+	conn->fn = fn;
+	STAILQ_INSERT_TAIL(&poll_group->connections, conn, link);
+}
+
+static void
+spdk_iscsi_poll_group_remove_conn(struct spdk_iscsi_conn *conn)
+{
+	struct spdk_iscsi_poll_group *poll_group = &g_spdk_iscsi.poll_group[spdk_env_get_current_core()];
+
+	STAILQ_REMOVE(&poll_group->connections, conn, spdk_iscsi_conn, link);
+}
+
 /**
  * \brief Create an iSCSI connection from the given parameters and schedule it
  *        on a reactor.
@@ -285,8 +303,8 @@ error_return:
 
 	conn->lcore = spdk_env_get_current_core();
 	__sync_fetch_and_add(&g_num_connections[conn->lcore], 1);
-	conn->poller = spdk_poller_register(spdk_iscsi_conn_login_do_work, conn, 0);
 
+	spdk_iscsi_poll_group_add_conn(conn, spdk_iscsi_conn_login_do_work);
 	return 0;
 }
 
@@ -563,8 +581,9 @@ spdk_iscsi_conn_stop_poller(struct spdk_iscsi_conn *conn)
 		assert(conn->dev != NULL);
 		spdk_scsi_dev_free_io_channels(conn->dev);
 	}
+
 	__sync_fetch_and_sub(&g_num_connections[spdk_env_get_current_core()], 1);
-	spdk_poller_unregister(&conn->poller);
+	spdk_iscsi_poll_group_remove_conn(conn);
 }
 
 void spdk_shutdown_iscsi_conns(void)
@@ -1144,8 +1163,7 @@ spdk_iscsi_conn_full_feature_migrate(void *arg1, void *arg2)
 
 	/* The poller has been unregistered, so now we can re-register it on the new core. */
 	conn->lcore = spdk_env_get_current_core();
-	conn->poller = spdk_poller_register(spdk_iscsi_conn_full_feature_do_work, conn,
-					    0);
+	spdk_iscsi_poll_group_add_conn(conn, spdk_iscsi_conn_full_feature_do_work);
 }
 
 void
@@ -1195,7 +1213,8 @@ spdk_iscsi_conn_login_do_work(void *arg)
 		spdk_iscsi_conn_stop_poller(conn);
 
 		__sync_fetch_and_add(&g_num_connections[lcore], 1);
-		event = spdk_event_allocate(lcore, spdk_iscsi_conn_full_feature_migrate, conn, NULL);
+		event = spdk_event_allocate(lcore, spdk_iscsi_conn_full_feature_migrate,
+					    conn, NULL);
 		spdk_event_call(event);
 	}
 }

lib/iscsi/conn.h

@@ -67,6 +67,7 @@
 #define TRACE_ISCSI_CONN_IDLE		SPDK_TPOINT_ID(TRACE_GROUP_ISCSI, 0x7)
 
 struct spdk_poller;
+typedef void (*spdk_iscsi_conn_fn)(void *arg);
 
 struct spdk_iscsi_conn {
 	int				id;
@@ -159,7 +160,7 @@ struct spdk_iscsi_conn {
 	char *partial_text_parameter;
 
 	STAILQ_ENTRY(spdk_iscsi_conn) link;
-	struct spdk_poller	*poller;
+	spdk_iscsi_conn_fn	fn;
 	struct spdk_poller	*flush_poller;
 	TAILQ_HEAD(queued_r2t_tasks, spdk_iscsi_task)	queued_r2t_tasks;
 	TAILQ_HEAD(active_r2t_tasks, spdk_iscsi_task)	active_r2t_tasks;

lib/iscsi/iscsi.h

@@ -39,6 +39,8 @@
 
 #include "spdk/bdev.h"
 #include "spdk/iscsi_spec.h"
+#include "spdk/event.h"
+#include "spdk/io_channel.h"
 
 #include "iscsi/param.h"
 #include "iscsi/tgt_node.h"
@@ -254,6 +256,12 @@ struct spdk_iscsi_sess {
 	uint32_t current_text_itt;
 };
 
+struct spdk_iscsi_poll_group {
+	uint32_t					core;
+	struct spdk_poller				*poller;
+	STAILQ_HEAD(connections, spdk_iscsi_conn)	connections;
+};
+
 struct spdk_iscsi_globals {
 	char *authfile;
 	char *nodebase;
@@ -288,6 +296,7 @@ struct spdk_iscsi_globals {
 	struct spdk_mempool *task_pool;
 
 	struct spdk_iscsi_sess	**session;
+	struct spdk_iscsi_poll_group *poll_group;
 };
 
 #define ISCSI_SECURITY_NEGOTIATION_PHASE	0

lib/iscsi/iscsi_subsystem.c

@@ -818,7 +818,6 @@ spdk_iscsi_app_read_parameters(void)
 	return 0;
 }
 
-
 static void
 spdk_iscsi_init_complete(int rc)
 {
@@ -831,6 +830,52 @@ spdk_iscsi_init_complete(int rc)
 	cb_fn(cb_arg, rc);
 }
 
+static void
+spdk_iscsi_poll_group_poll(void *ctx)
+{
+	struct spdk_iscsi_poll_group *group = ctx;
+	struct spdk_iscsi_conn *conn, *tmp;
+
+	STAILQ_FOREACH_SAFE(conn, &group->connections, link, tmp) {
+		conn->fn(conn);
+	}
+}
+
+static void
+iscsi_create_poll_group_done(void *ctx)
+{
+	spdk_iscsi_init_complete(0);
+}
+
+static void
+iscsi_create_poll_group(void *ctx)
+{
+	struct spdk_iscsi_poll_group *pg;
+
+	pg = &g_spdk_iscsi.poll_group[spdk_env_get_current_core()];
+	pg->core = spdk_env_get_current_core();
+	assert(pg != NULL);
+
+	STAILQ_INIT(&pg->connections);
+	pg->poller = spdk_poller_register(spdk_iscsi_poll_group_poll, pg, 0);
+}
+
+static void
+spdk_initialize_iscsi_poll_group(void)
+{
+	size_t g_num_poll_groups = spdk_env_get_last_core() + 1;
+
+	g_spdk_iscsi.poll_group = calloc(g_num_poll_groups, sizeof(struct spdk_iscsi_poll_group));
+	if (!g_spdk_iscsi.poll_group) {
+		SPDK_ERRLOG("Failed to allocated iscsi poll group\n");
+		spdk_iscsi_init_complete(-1);
+		return;
+	}
+
+	/* Send a message to each thread and create a poll group */
+	spdk_for_each_thread(iscsi_create_poll_group, NULL, iscsi_create_poll_group_done);
+}
+
 void
 spdk_iscsi_init(spdk_iscsi_init_cb cb_fn, void *cb_arg)
 {
@@ -868,7 +913,7 @@ spdk_iscsi_init(spdk_iscsi_init_cb cb_fn, void *cb_arg)
 		return;
 	}
 
-	spdk_iscsi_init_complete(0);
+	spdk_initialize_iscsi_poll_group();
 }
 
 void
@@ -892,6 +937,7 @@ spdk_iscsi_fini_done(void)
 	spdk_iscsi_portal_grp_array_destroy();
 	free(g_spdk_iscsi.authfile);
 	free(g_spdk_iscsi.nodebase);
+	free(g_spdk_iscsi.poll_group);
 
 	pthread_mutex_destroy(&g_spdk_iscsi.mutex);
 	g_fini_cb_fn(g_fini_cb_arg);