Re: [PATCH v3] target: add iscsi/cpus_allowed_list in configfs

Zou Mingzhe
2022-03-08T08:34:43Z

Hi, christie

Have you started reviewing this patch?

Mingzhe

在 2022/3/1 15:55, mingzhe.zou@easystack.cn 写道:
> From: Mingzhe Zou <mingzhe.zou@easystack.cn>
>
> The RX/TX threads for iSCSI connection can be scheduled to
> any online cpus, and will not be rescheduled.
>
> If bind other heavy load threads with iSCSI connection
> RX/TX thread to the same cpu, the iSCSI performance will
> be worse.
>
> This patch add iscsi/cpus_allowed_list in configfs. The
> available cpus set of iSCSI connection RX/TX threads is
> allowed_cpus & online_cpus. If it is modified, all RX/TX
> threads will be rescheduled.
>
> Signed-off-by: Mingzhe Zou <mingzhe.zou@easystack.cn>
> ---
> drivers/target/iscsi/iscsi_target.c | 77 +++++++++++++++++++-
> drivers/target/iscsi/iscsi_target_configfs.c | 32 ++++++++
> drivers/target/iscsi/iscsi_target_login.c | 8 ++
> include/target/iscsi/iscsi_target_core.h | 31 ++------
> 4 files changed, 120 insertions(+), 28 deletions(-)
>
> diff --git a/drivers/target/iscsi/iscsi_target.c b/drivers/target/iscsi/iscsi_target.c
> index 2c54c5d8412d..6fe6a6bab3f4 100644
> --- a/drivers/target/iscsi/iscsi_target.c
> +++ b/drivers/target/iscsi/iscsi_target.c
> @@ -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)
> {
> diff --git a/drivers/target/iscsi/iscsi_target_configfs.c b/drivers/target/iscsi/iscsi_target_configfs.c
> index 2a9de24a8bbe..0cedcfe207b5 100644
> --- a/drivers/target/iscsi/iscsi_target_configfs.c
> +++ b/drivers/target/iscsi/iscsi_target_configfs.c
> @@ -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,
> };
>
> diff --git a/drivers/target/iscsi/iscsi_target_login.c b/drivers/target/iscsi/iscsi_target_login.c
> index 1a9c50401bdb..9c01fb864585 100644
> --- a/drivers/target/iscsi/iscsi_target_login.c
> +++ b/drivers/target/iscsi/iscsi_target_login.c
> @@ -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);
> diff --git a/include/target/iscsi/iscsi_target_core.h b/include/target/iscsi/iscsi_target_core.h
> index 1eccb2ac7d02..adc87de0362b 100644
> --- a/include/target/iscsi/iscsi_target_core.h
> +++ b/include/target/iscsi/iscsi_target_core.h
> @@ -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,
> - 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);
> -}
> +extern void iscsit_thread_check_cpumask(struct iscsi_conn *conn,
> + struct task_struct *p,
> + int mode);
> +
> #endif /* ISCSI_TARGET_CORE_H */