Commit d72d827f authored by Mingzhe Zou's avatar Mingzhe Zou Committed by Martin K. Petersen
Browse files

scsi: target: Add iscsi/cpus_allowed_list in configfs 

The RX/TX threads for iSCSI connection can be scheduled to any online CPUs,
and will not be rescheduled.

When binding other heavy load threads along with iSCSI connection RX/TX
thread to the same CPU, the iSCSI performance will be worse.

Add iscsi/cpus_allowed_list in configfs. The available CPU set of iSCSI
connection RX/TX threads is allowed_cpus & online_cpus. If it is modified,
all RX/TX threads will be rescheduled.

Link: https://lore.kernel.org/r/20220301075500.14266-1-mingzhe.zou@easystack.cn


Reviewed-by: default avatarMike Christie <michael.christie@oracle.com>
Signed-off-by: default avatarMingzhe Zou <mingzhe.zou@easystack.cn>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent 095478a6

drivers/target/iscsi/iscsi_target.c

+74 −3
Original line number Diff line number Diff line
@@ -702,13 +702,19 @@ static int __init iscsi_target_init_module(void) 
	if (!iscsit_global->ts_bitmap)

		goto configfs_out;



	if (!zalloc_cpumask_var(&iscsit_global->allowed_cpumask, GFP_KERNEL)) {

		pr_err("Unable to allocate iscsit_global->allowed_cpumask\n");

		goto bitmap_out;

	}

	cpumask_setall(iscsit_global->allowed_cpumask);



	lio_qr_cache = kmem_cache_create("lio_qr_cache",

			sizeof(struct iscsi_queue_req),

			__alignof__(struct iscsi_queue_req), 0, NULL);

	if (!lio_qr_cache) {

		pr_err("Unable to kmem_cache_create() for"

				" lio_qr_cache\n");

		goto bitmap_out;

		goto cpumask_out;

	}



	lio_dr_cache = kmem_cache_create("lio_dr_cache",
@@ -753,6 +759,8 @@ static int __init iscsi_target_init_module(void) 
	kmem_cache_destroy(lio_dr_cache);

qr_out:

	kmem_cache_destroy(lio_qr_cache);

cpumask_out:

	free_cpumask_var(iscsit_global->allowed_cpumask);

bitmap_out:

	vfree(iscsit_global->ts_bitmap);

configfs_out:
@@ -782,6 +790,7 @@ static void __exit iscsi_target_cleanup_module(void) 


	target_unregister_template(&iscsi_ops);



	free_cpumask_var(iscsit_global->allowed_cpumask);

	vfree(iscsit_global->ts_bitmap);

	kfree(iscsit_global);

}
@@ -3587,6 +3596,11 @@ static int iscsit_send_reject( 
void iscsit_thread_get_cpumask(struct iscsi_conn *conn)

{

	int ord, cpu;

	cpumask_t conn_allowed_cpumask;



	cpumask_and(&conn_allowed_cpumask, iscsit_global->allowed_cpumask,

		    cpu_online_mask);



	/*

	 * bitmap_id is assigned from iscsit_global->ts_bitmap from

	 * within iscsit_start_kthreads()
@@ -3595,8 +3609,9 @@ void iscsit_thread_get_cpumask(struct iscsi_conn *conn) 
	 * iSCSI connection's RX/TX threads will be scheduled to

	 * execute upon.

	 */

	ord = conn->bitmap_id % cpumask_weight(cpu_online_mask);

	for_each_online_cpu(cpu) {

	cpumask_clear(conn->conn_cpumask);

	ord = conn->bitmap_id % cpumask_weight(&conn_allowed_cpumask);

	for_each_cpu(cpu, &conn_allowed_cpumask) {

		if (ord-- == 0) {

			cpumask_set_cpu(cpu, conn->conn_cpumask);

			return;
@@ -3609,6 +3624,62 @@ void iscsit_thread_get_cpumask(struct iscsi_conn *conn) 
	cpumask_setall(conn->conn_cpumask);

}



static void iscsit_thread_reschedule(struct iscsi_conn *conn)

{

	/*

	 * If iscsit_global->allowed_cpumask modified, reschedule iSCSI

	 * connection's RX/TX threads update conn->allowed_cpumask.

	 */

	if (!cpumask_equal(iscsit_global->allowed_cpumask,

			   conn->allowed_cpumask)) {

		iscsit_thread_get_cpumask(conn);

		conn->conn_tx_reset_cpumask = 1;

		conn->conn_rx_reset_cpumask = 1;

		cpumask_copy(conn->allowed_cpumask,

			     iscsit_global->allowed_cpumask);

	}

}



void iscsit_thread_check_cpumask(

	struct iscsi_conn *conn,

	struct task_struct *p,

	int mode)

{

	/*

	 * The TX and RX threads maybe call iscsit_thread_check_cpumask()

	 * at the same time. The RX thread might be faster and return from

	 * iscsit_thread_reschedule() with conn_rx_reset_cpumask set to 0.

	 * Then the TX thread sets it back to 1.

	 * The next time the RX thread loops, it sees conn_rx_reset_cpumask

	 * set to 1 and calls set_cpus_allowed_ptr() again and set it to 0.

	 */

	iscsit_thread_reschedule(conn);



	/*

	 * mode == 1 signals iscsi_target_tx_thread() usage.

	 * mode == 0 signals iscsi_target_rx_thread() usage.

	 */

	if (mode == 1) {

		if (!conn->conn_tx_reset_cpumask)

			return;

	} else {

		if (!conn->conn_rx_reset_cpumask)

			return;

	}



	/*

	 * Update the CPU mask for this single kthread so that

	 * both TX and RX kthreads are scheduled to run on the

	 * same CPU.

	 */

	set_cpus_allowed_ptr(p, conn->conn_cpumask);

	if (mode == 1)

		conn->conn_tx_reset_cpumask = 0;

	else

		conn->conn_rx_reset_cpumask = 0;

}

EXPORT_SYMBOL(iscsit_thread_check_cpumask);



int

iscsit_immediate_queue(struct iscsi_conn *conn, struct iscsi_cmd *cmd, int state)

{

drivers/target/iscsi/iscsi_target_configfs.c

+32 −0
Original line number Diff line number Diff line
@@ -1127,8 +1127,40 @@ static ssize_t lio_target_wwn_lio_version_show(struct config_item *item, 


CONFIGFS_ATTR_RO(lio_target_wwn_, lio_version);



static ssize_t lio_target_wwn_cpus_allowed_list_show(

		struct config_item *item, char *page)

{

	return sprintf(page, "%*pbl\n",

		       cpumask_pr_args(iscsit_global->allowed_cpumask));

}



static ssize_t lio_target_wwn_cpus_allowed_list_store(

		struct config_item *item, const char *page, size_t count)

{

	int ret;

	char *orig;

	cpumask_t new_allowed_cpumask;



	orig = kstrdup(page, GFP_KERNEL);

	if (!orig)

		return -ENOMEM;



	cpumask_clear(&new_allowed_cpumask);

	ret = cpulist_parse(orig, &new_allowed_cpumask);



	kfree(orig);

	if (ret != 0)

		return ret;



	cpumask_copy(iscsit_global->allowed_cpumask, &new_allowed_cpumask);

	return count;

}



CONFIGFS_ATTR(lio_target_wwn_, cpus_allowed_list);



static struct configfs_attribute *lio_target_wwn_attrs[] = {

	&lio_target_wwn_attr_lio_version,

	&lio_target_wwn_attr_cpus_allowed_list,

	NULL,

};

drivers/target/iscsi/iscsi_target_login.c

+8 −0
Original line number Diff line number Diff line
@@ -1129,8 +1129,15 @@ static struct iscsi_conn *iscsit_alloc_conn(struct iscsi_np *np) 
		goto free_conn_ops;

	}



	if (!zalloc_cpumask_var(&conn->allowed_cpumask, GFP_KERNEL)) {

		pr_err("Unable to allocate conn->allowed_cpumask\n");

		goto free_conn_cpumask;

	}



	return conn;



free_conn_cpumask:

	free_cpumask_var(conn->conn_cpumask);

free_conn_ops:

	kfree(conn->conn_ops);

put_transport:
@@ -1142,6 +1149,7 @@ static struct iscsi_conn *iscsit_alloc_conn(struct iscsi_np *np) 


void iscsit_free_conn(struct iscsi_conn *conn)

{

	free_cpumask_var(conn->allowed_cpumask);

	free_cpumask_var(conn->conn_cpumask);

	kfree(conn->conn_ops);

	iscsit_put_transport(conn->conn_transport);

include/target/iscsi/iscsi_target_core.h

+6 −25
Original line number Diff line number Diff line
@@ -580,6 +580,7 @@ struct iscsi_conn { 
	struct ahash_request	*conn_tx_hash;

	/* Used for scheduling TX and RX connection kthreads */

	cpumask_var_t		conn_cpumask;

	cpumask_var_t		allowed_cpumask;

	unsigned int		conn_rx_reset_cpumask:1;

	unsigned int		conn_tx_reset_cpumask:1;

	/* list_head of struct iscsi_cmd for this connection */
@@ -878,6 +879,7 @@ struct iscsit_global { 
	/* Thread Set bitmap pointer */

	unsigned long		*ts_bitmap;

	spinlock_t		ts_bitmap_lock;

	cpumask_var_t		allowed_cpumask;

	/* Used for iSCSI discovery session authentication */

	struct iscsi_node_acl	discovery_acl;

	struct iscsi_portal_group	*discovery_tpg;
@@ -898,29 +900,8 @@ static inline u32 session_get_next_ttt(struct iscsi_session *session) 


extern struct iscsi_cmd *iscsit_find_cmd_from_itt(struct iscsi_conn *, itt_t);



static inline void iscsit_thread_check_cpumask(

	struct iscsi_conn *conn,

extern void iscsit_thread_check_cpumask(struct iscsi_conn *conn,

					struct task_struct *p,

	int mode)

{

	/*

	 * mode == 1 signals iscsi_target_tx_thread() usage.

	 * mode == 0 signals iscsi_target_rx_thread() usage.

	 */

	if (mode == 1) {

		if (!conn->conn_tx_reset_cpumask)

			return;

		conn->conn_tx_reset_cpumask = 0;

	} else {

		if (!conn->conn_rx_reset_cpumask)

			return;

		conn->conn_rx_reset_cpumask = 0;

	}

	/*

	 * Update the CPU mask for this single kthread so that

	 * both TX and RX kthreads are scheduled to run on the

	 * same CPU.

	 */

	set_cpus_allowed_ptr(p, conn->conn_cpumask);

}

					int mode);



#endif /* ISCSI_TARGET_CORE_H */