From 5ab41ca467546d18dc793195a7c9f8e307311dbf Mon Sep 17 00:00:00 2001 From: Nicholas Bellinger Date: Thu, 5 Sep 2013 16:13:41 -0700 Subject: iscsi-target: Add thread_set->ts_activate_sem + use common deallocate This patch removes the iscsi_thread_set->[rx,tx]_post_start_comp that was originally used synchronize startup between rx and tx threads within a single thread_set. Instead, use a single ->ts_activate_sem in iscsi_activate_thread_set() to wait for both processes to awake in the RX/TX pre handlers. Also, go ahead and refactor thread_set deallocate code into a common iscsi_deallocate_thread_one(), and update iscsi_deallocate_thread_sets() and iscsi_deallocate_extra_thread_sets() use this code v3 changes: - Make iscsi_deallocate_thread_one defined as static (Fengguang) v2 changes: - Set ISCSI_THREAD_SET_ACTIVE before calling complete in iscsi_activate_thread_set - Protect ts->conn sanity checks with ->ts_state_lock in RX/TX pre handlers - Add ->ts_activate_sem to save extra context switches per iscsi_activate_thread_set() call. - Refactor thread_set shutdown into iscsi_deallocate_thread_one() Signed-off-by: Nicholas Bellinger --- drivers/target/iscsi/iscsi_target_tq.c | 139 ++++++++++++++------------------- drivers/target/iscsi/iscsi_target_tq.h | 5 +- 2 files changed, 59 insertions(+), 85 deletions(-) (limited to 'drivers/target') diff --git a/drivers/target/iscsi/iscsi_target_tq.c b/drivers/target/iscsi/iscsi_target_tq.c index 1a5bbec03f3e..ba0ac41889af 100644 --- a/drivers/target/iscsi/iscsi_target_tq.c +++ b/drivers/target/iscsi/iscsi_target_tq.c @@ -105,12 +105,11 @@ int iscsi_allocate_thread_sets(u32 thread_pair_count) ts->status = ISCSI_THREAD_SET_FREE; INIT_LIST_HEAD(&ts->ts_list); spin_lock_init(&ts->ts_state_lock); - init_completion(&ts->rx_post_start_comp); - init_completion(&ts->tx_post_start_comp); init_completion(&ts->rx_restart_comp); init_completion(&ts->tx_restart_comp); init_completion(&ts->rx_start_comp); init_completion(&ts->tx_start_comp); + sema_init(&ts->ts_activate_sem, 0); ts->create_threads = 1; ts->tx_thread = kthread_run(iscsi_target_tx_thread, ts, "%s", @@ -139,35 +138,44 @@ int iscsi_allocate_thread_sets(u32 thread_pair_count) return allocated_thread_pair_count; } -void iscsi_deallocate_thread_sets(void) +static void iscsi_deallocate_thread_one(struct iscsi_thread_set *ts) { - u32 released_count = 0; - struct iscsi_thread_set *ts = NULL; - - while ((ts = iscsi_get_ts_from_inactive_list())) { + spin_lock_bh(&ts->ts_state_lock); + ts->status = ISCSI_THREAD_SET_DIE; + if (ts->rx_thread) { + complete(&ts->rx_start_comp); + spin_unlock_bh(&ts->ts_state_lock); + kthread_stop(ts->rx_thread); spin_lock_bh(&ts->ts_state_lock); - ts->status = ISCSI_THREAD_SET_DIE; + } + if (ts->tx_thread) { + complete(&ts->tx_start_comp); spin_unlock_bh(&ts->ts_state_lock); + kthread_stop(ts->tx_thread); + spin_lock_bh(&ts->ts_state_lock); + } + spin_unlock_bh(&ts->ts_state_lock); + /* + * Release this thread_id in the thread_set_bitmap + */ + spin_lock(&ts_bitmap_lock); + bitmap_release_region(iscsit_global->ts_bitmap, + ts->thread_id, get_order(1)); + spin_unlock(&ts_bitmap_lock); - if (ts->rx_thread) { - send_sig(SIGINT, ts->rx_thread, 1); - kthread_stop(ts->rx_thread); - } - if (ts->tx_thread) { - send_sig(SIGINT, ts->tx_thread, 1); - kthread_stop(ts->tx_thread); - } - /* - * Release this thread_id in the thread_set_bitmap - */ - spin_lock(&ts_bitmap_lock); - bitmap_release_region(iscsit_global->ts_bitmap, - ts->thread_id, get_order(1)); - spin_unlock(&ts_bitmap_lock); + kfree(ts); +} + +void iscsi_deallocate_thread_sets(void) +{ + struct iscsi_thread_set *ts = NULL; + u32 released_count = 0; + while ((ts = iscsi_get_ts_from_inactive_list())) { + + iscsi_deallocate_thread_one(ts); released_count++; - kfree(ts); } if (released_count) @@ -187,38 +195,13 @@ static void iscsi_deallocate_extra_thread_sets(void) if (!ts) break; - spin_lock_bh(&ts->ts_state_lock); - ts->status = ISCSI_THREAD_SET_DIE; - - if (ts->rx_thread) { - complete(&ts->rx_start_comp); - spin_unlock_bh(&ts->ts_state_lock); - kthread_stop(ts->rx_thread); - spin_lock_bh(&ts->ts_state_lock); - } - if (ts->tx_thread) { - complete(&ts->tx_start_comp); - spin_unlock_bh(&ts->ts_state_lock); - kthread_stop(ts->tx_thread); - spin_lock_bh(&ts->ts_state_lock); - } - spin_unlock_bh(&ts->ts_state_lock); - /* - * Release this thread_id in the thread_set_bitmap - */ - spin_lock(&ts_bitmap_lock); - bitmap_release_region(iscsit_global->ts_bitmap, - ts->thread_id, get_order(1)); - spin_unlock(&ts_bitmap_lock); - + iscsi_deallocate_thread_one(ts); released_count++; - kfree(ts); } - if (released_count) { + if (released_count) pr_debug("Stopped %d thread set(s) (%d total threads)." "\n", released_count, released_count * 2); - } } void iscsi_activate_thread_set(struct iscsi_conn *conn, struct iscsi_thread_set *ts) @@ -228,14 +211,13 @@ void iscsi_activate_thread_set(struct iscsi_conn *conn, struct iscsi_thread_set spin_lock_bh(&ts->ts_state_lock); conn->thread_set = ts; ts->conn = conn; + ts->status = ISCSI_THREAD_SET_ACTIVE; spin_unlock_bh(&ts->ts_state_lock); - /* - * Start up the RX thread and wait on rx_post_start_comp. The RX - * Thread will then do the same for the TX Thread in - * iscsi_rx_thread_pre_handler(). - */ + complete(&ts->rx_start_comp); - wait_for_completion(&ts->rx_post_start_comp); + complete(&ts->tx_start_comp); + + down(&ts->ts_activate_sem); } struct iscsi_thread_set *iscsi_get_thread_set(void) @@ -267,6 +249,7 @@ get_set: ts->thread_count = 2; init_completion(&ts->rx_restart_comp); init_completion(&ts->tx_restart_comp); + sema_init(&ts->ts_activate_sem, 0); return ts; } @@ -452,18 +435,19 @@ sleep: if (iscsi_signal_thread_pre_handler(ts) < 0) return NULL; + iscsi_check_to_add_additional_sets(); + + spin_lock_bh(&ts->ts_state_lock); if (!ts->conn) { pr_err("struct iscsi_thread_set->conn is NULL for" - " thread_id: %d, going back to sleep\n", ts->thread_id); - goto sleep; + " RX thread_id: %s/%d\n", current->comm, current->pid); + spin_unlock_bh(&ts->ts_state_lock); + return NULL; } - iscsi_check_to_add_additional_sets(); - /* - * The RX Thread starts up the TX Thread and sleeps. - */ ts->thread_clear |= ISCSI_CLEAR_RX_THREAD; - complete(&ts->tx_start_comp); - wait_for_completion(&ts->tx_post_start_comp); + spin_unlock_bh(&ts->ts_state_lock); + + up(&ts->ts_activate_sem); return ts->conn; } @@ -505,27 +489,20 @@ sleep: if (iscsi_signal_thread_pre_handler(ts) < 0) return NULL; - if (!ts->conn) { - pr_err("struct iscsi_thread_set->conn is NULL for " - " thread_id: %d, going back to sleep\n", - ts->thread_id); - goto sleep; - } - iscsi_check_to_add_additional_sets(); - /* - * From the TX thread, up the tx_post_start_comp that the RX Thread is - * sleeping on in iscsi_rx_thread_pre_handler(), then up the - * rx_post_start_comp that iscsi_activate_thread_set() is sleeping on. - */ - ts->thread_clear |= ISCSI_CLEAR_TX_THREAD; - complete(&ts->tx_post_start_comp); - complete(&ts->rx_post_start_comp); spin_lock_bh(&ts->ts_state_lock); - ts->status = ISCSI_THREAD_SET_ACTIVE; + if (!ts->conn) { + pr_err("struct iscsi_thread_set->conn is NULL for" + " TX thread_id: %s/%d\n", current->comm, current->pid); + spin_unlock_bh(&ts->ts_state_lock); + return NULL; + } + ts->thread_clear |= ISCSI_CLEAR_TX_THREAD; spin_unlock_bh(&ts->ts_state_lock); + up(&ts->ts_activate_sem); + return ts->conn; } diff --git a/drivers/target/iscsi/iscsi_target_tq.h b/drivers/target/iscsi/iscsi_target_tq.h index 547d11831282..cc1eede5ab3a 100644 --- a/drivers/target/iscsi/iscsi_target_tq.h +++ b/drivers/target/iscsi/iscsi_target_tq.h @@ -64,10 +64,6 @@ struct iscsi_thread_set { struct iscsi_conn *conn; /* used for controlling ts state accesses */ spinlock_t ts_state_lock; - /* Used for rx side post startup */ - struct completion rx_post_start_comp; - /* Used for tx side post startup */ - struct completion tx_post_start_comp; /* used for restarting thread queue */ struct completion rx_restart_comp; /* used for restarting thread queue */ @@ -82,6 +78,7 @@ struct iscsi_thread_set { struct task_struct *tx_thread; /* struct iscsi_thread_set in list list head*/ struct list_head ts_list; + struct semaphore ts_activate_sem; }; #endif /*** ISCSI_THREAD_QUEUE_H ***/ -- cgit v1.2.3-59-g8ed1b