Commit fb641c4b authored by Ben Walker's avatar Ben Walker Committed by Jim Harris
Browse files

iscsi: Assign connections to poll groups instead of lcores. 



This patch binds poll groups to SPDK thread through IO channel and
assigns connections to poll groups instead of cores.

iSCSI subsystem registers iSCSI global object as an IO device, and create
poll groups as context of IO channels of the IO device.

Each portal get and hold portal group on which the corresponding acceptor is
running.

When a connection is constructed, iSCSI subsystem assigns a poll group
to the connection by getting it from the corresponding portal.

When a connection enters full-feature phase, iSCSI subsystem schedules
the connection to a poll group by round-robin.

Then, each connection can know its running SPDK thread directly and can
use SPDK message passing infrastructure instead of SPDK event framework.

By this change, iSCSI connections are binded to SPDK thread, and not
binded to processor core anymore.

Some other changes in this patch are
- core ID is removed from the output of get_iscsi_connections RPC. The
  upcoming patches will change the RPC to use spdk_for_each_channel and can
  access SPDK thread safely, and add SPDK thread ID instead.
- utilize UT multithread framework added by the last patch to test
  iSCSI poll groups by UT.

Change-Id: Iec73c778aa413bcabdb63141cc41d4160911ea0e
Signed-off-by: default avatarBen Walker <benjamin.walker@intel.com>
Signed-off-by: default avatarShuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Reviewed-on: https://review.gerrithub.io/c/spdk/spdk/+/463359


Reviewed-by: default avatarBroadcom SPDK FC-NVMe CI <spdk-ci.pdl@broadcom.com>
Reviewed-by: default avatarJim Harris <james.r.harris@intel.com>
Tested-by: default avatarSPDK CI Jenkins <sys_sgci@intel.com>
parent 566aa11e

app/iscsi_top/iscsi_top.cpp

+5 −4
Original line number Diff line number Diff line
@@ -53,14 +53,15 @@ static void usage(void) 
		" (required)\n");

}



/* Group by poll group */

static bool

conns_compare(struct spdk_iscsi_conn *first, struct spdk_iscsi_conn *second)

{

	if (first->lcore < second->lcore) {

	if ((uintptr_t)first->pg < (uintptr_t)second->pg) {

		return true;

	}



	if (first->lcore > second->lcore) {

	if ((uintptr_t)first->pg > (uintptr_t)second->pg) {

		return false;

	}
@@ -110,8 +111,8 @@ print_connections(void) 
	stable_sort(v.begin(), v.end(), conns_compare);

	for (iter = v.begin(); iter != v.end(); iter++) {

		conn = *iter;

		printf("lcore %2d conn %3d T:%-8s I:%s (%s)\n",

		       conn->lcore, conn->id,

		printf("pg %p conn %3d T:%-8s I:%s (%s)\n",

		       conn->pg, conn->id,

		       conn->target_short_name, conn->initiator_name,

		       conn->initiator_addr);

	}

lib/iscsi/conn.c

+40 −51
Original line number Diff line number Diff line
@@ -70,7 +70,7 @@ static pthread_mutex_t g_conns_mutex = PTHREAD_MUTEX_INITIALIZER; 


static struct spdk_poller *g_shutdown_timer = NULL;



static void iscsi_conn_full_feature_migrate(void *arg1, void *arg2);

static void iscsi_conn_full_feature_migrate(void *arg);

static void iscsi_conn_stop(struct spdk_iscsi_conn *conn);

static void iscsi_conn_sock_cb(void *arg, struct spdk_sock_group *group,

			       struct spdk_sock *sock);
@@ -296,9 +296,12 @@ spdk_iscsi_conn_construct(struct spdk_iscsi_portal *portal, 
	SPDK_DEBUGLOG(SPDK_LOG_ISCSI, "Launching connection on acceptor thread\n");

	conn->pending_task_cnt = 0;



	conn->lcore = spdk_env_get_current_core();

	pg = &g_spdk_iscsi.poll_group[conn->lcore];

	/* Get the acceptor poll group */

	pg = portal->acceptor_pg;



	assert(spdk_io_channel_get_thread(spdk_io_channel_from_ctx(pg)) == spdk_get_thread());



	conn->pg = pg;

	iscsi_poll_group_add_conn(pg, conn);

	return 0;
@@ -477,15 +480,11 @@ _iscsi_conn_check_shutdown(void *arg) 
static void

_iscsi_conn_destruct(struct spdk_iscsi_conn *conn)

{

	struct spdk_iscsi_poll_group *pg;

	int rc;



	spdk_clear_all_transfer_task(conn, NULL, NULL);



	assert(conn->lcore == spdk_env_get_current_core());

	pg = &g_spdk_iscsi.poll_group[conn->lcore];



	iscsi_poll_group_remove_conn(pg, conn);

	iscsi_poll_group_remove_conn(conn->pg, conn);

	spdk_sock_close(&conn->sock);

	spdk_poller_unregister(&conn->logout_timer);
@@ -610,7 +609,8 @@ iscsi_conn_remove_lun(struct spdk_scsi_lun *lun, void *remove_ctx) 
	struct spdk_iscsi_pdu *pdu, *tmp_pdu;

	struct spdk_iscsi_task *iscsi_task, *tmp_iscsi_task;



	assert(conn->lcore == spdk_env_get_current_core());

	assert(spdk_io_channel_get_thread(spdk_io_channel_from_ctx(conn->pg)) ==

	       spdk_get_thread());



	/* If a connection is already in stating status, just return */

	if (conn->state >= ISCSI_CONN_STATE_EXITING) {
@@ -703,7 +703,8 @@ iscsi_conn_stop(struct spdk_iscsi_conn *conn) 
		iscsi_conn_close_luns(conn);

	}



	assert(conn->lcore == spdk_env_get_current_core());

	assert(spdk_io_channel_get_thread(spdk_io_channel_from_ctx(conn->pg)) ==

	       spdk_get_thread());

}



void
@@ -1393,54 +1394,32 @@ iscsi_conn_sock_cb(void *arg, struct spdk_sock_group *group, struct spdk_sock *s 
}



static void

iscsi_conn_full_feature_migrate(void *arg1, void *arg2)

iscsi_conn_full_feature_migrate(void *arg)

{

	struct spdk_iscsi_conn *conn = arg1;

	struct spdk_iscsi_poll_group *pg;

	struct spdk_iscsi_conn *conn = arg;



	if (conn->sess->session_type == SESSION_TYPE_NORMAL) {

		iscsi_conn_open_luns(conn);

	}



	/* The poller has been unregistered, so now we can re-register it on the new core. */

	conn->lcore = spdk_env_get_current_core();

	pg = &g_spdk_iscsi.poll_group[conn->lcore];

	iscsi_poll_group_add_conn(pg, conn);

	/* Add this connection to the assigned poll group. */

	iscsi_poll_group_add_conn(conn->pg, conn);

}



static uint32_t g_next_core = SPDK_ENV_LCORE_ID_ANY;

static struct spdk_iscsi_poll_group *g_next_pg = NULL;



void

spdk_iscsi_conn_schedule(struct spdk_iscsi_conn *conn)

{

	struct spdk_iscsi_poll_group	*pg;

	struct spdk_event		*event;

	struct spdk_iscsi_tgt_node	*target;

	uint32_t			i;

	uint32_t			lcore;



	lcore = SPDK_ENV_LCORE_ID_ANY;



	if (conn->sess->session_type != SESSION_TYPE_NORMAL) {

		/* Leave all non-normal sessions on the acceptor

		 * thread. */

		return;

	}



	for (i = 0; i < spdk_env_get_core_count(); i++) {

		if (g_next_core > spdk_env_get_last_core()) {

			g_next_core = spdk_env_get_first_core();

		}



		lcore = g_next_core;

		g_next_core = spdk_env_get_next_core(g_next_core);

		break;

	}



	if (i >= spdk_env_get_core_count()) {

		SPDK_ERRLOG("Unable to schedule connection on allowed CPU core. Scheduling on first core instead.\n");

		lcore = spdk_env_get_first_core();

	}

	pthread_mutex_lock(&g_spdk_iscsi.mutex);



	target = conn->sess->target;

	pthread_mutex_lock(&target->mutex);
@@ -1448,29 +1427,39 @@ spdk_iscsi_conn_schedule(struct spdk_iscsi_conn *conn) 
	if (target->num_active_conns == 1) {

		/**

		 * This is the only active connection for this target node.

		 *  Save the lcore in the target node so it can be used for

		 *  any other connections to this target node.

		 *  Pick a poll group using round-robin.

		 */

		target->lcore = lcore;

		if (g_next_pg == NULL) {

			g_next_pg = TAILQ_FIRST(&g_spdk_iscsi.poll_group_head);

			assert(g_next_pg != NULL);

		}



		pg = g_next_pg;

		g_next_pg = TAILQ_NEXT(g_next_pg, link);



		/* Save the pg in the target node so it can be used for any other connections to this target node. */

		target->pg = pg;

	} else {

		/**

		 * There are other active connections for this target node.

		 *  Ignore the lcore specified by the allocator and use the

		 *  the target node's lcore to ensure this connection runs on

		 *  the same lcore as other connections for this target node.

		 */

		lcore = target->lcore;

		pg = target->pg;

	}



	pthread_mutex_unlock(&target->mutex);

	pthread_mutex_unlock(&g_spdk_iscsi.mutex);



	assert(conn->lcore == spdk_env_get_current_core());

	pg = &g_spdk_iscsi.poll_group[conn->lcore];

	iscsi_poll_group_remove_conn(pg, conn);

	assert(spdk_io_channel_get_thread(spdk_io_channel_from_ctx(conn->pg)) ==

	       spdk_get_thread());



	/* Remove this connection from the previous poll group */

	iscsi_poll_group_remove_conn(conn->pg, conn);



	conn->last_nopin = spdk_get_ticks();

	event = spdk_event_allocate(lcore, iscsi_conn_full_feature_migrate,

				    conn, NULL);

	spdk_event_call(event);

	conn->pg = pg;



	spdk_thread_send_msg(spdk_io_channel_get_thread(spdk_io_channel_from_ctx(pg)),

			     iscsi_conn_full_feature_migrate, conn);

}



static int

lib/iscsi/conn.h

+1 −1
Original line number Diff line number Diff line
@@ -82,7 +82,7 @@ struct spdk_iscsi_conn { 
	int				pg_tag;

	char				*portal_host;

	char				*portal_port;

	uint32_t			lcore;

	struct spdk_iscsi_poll_group	*pg;

	struct spdk_sock		*sock;

	struct spdk_iscsi_sess		*sess;

lib/iscsi/iscsi.c

+1 −0
Original line number Diff line number Diff line
@@ -73,6 +73,7 @@ struct spdk_iscsi_globals g_spdk_iscsi = { 
	.ig_head = TAILQ_HEAD_INITIALIZER(g_spdk_iscsi.ig_head),

	.target_head = TAILQ_HEAD_INITIALIZER(g_spdk_iscsi.target_head),

	.auth_group_head = TAILQ_HEAD_INITIALIZER(g_spdk_iscsi.auth_group_head),

	.poll_group_head = TAILQ_HEAD_INITIALIZER(g_spdk_iscsi.poll_group_head),

};



/* random value generation */

lib/iscsi/iscsi.h

+2 −2
Original line number Diff line number Diff line
@@ -280,11 +280,11 @@ struct spdk_iscsi_sess { 
};



struct spdk_iscsi_poll_group {

	uint32_t					core;

	struct spdk_poller				*poller;

	struct spdk_poller				*nop_poller;

	STAILQ_HEAD(connections, spdk_iscsi_conn)	connections;

	struct spdk_sock_group				*sock_group;

	TAILQ_ENTRY(spdk_iscsi_poll_group)		link;

};



struct spdk_iscsi_opts {
@@ -318,6 +318,7 @@ struct spdk_iscsi_globals { 
	TAILQ_HEAD(, spdk_iscsi_init_grp)	ig_head;

	TAILQ_HEAD(, spdk_iscsi_tgt_node)	target_head;

	TAILQ_HEAD(, spdk_iscsi_auth_group)	auth_group_head;

	TAILQ_HEAD(, spdk_iscsi_poll_group)	poll_group_head;



	int32_t timeout;

	int32_t nopininterval;
@@ -344,7 +345,6 @@ 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