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iscsi-target: Add thread_set->ts_activate_sem + use common deallocate

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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 <nab@linux-iscsi.org>
This commit is contained in:
Nicholas Bellinger 2013-09-05 16:13:41 -07:00
parent d5705c4ab5
commit 5ab41ca467
2 changed files with 59 additions and 85 deletions
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139
drivers/target/iscsi/iscsi_target_tq.c
View file

@ -105,12 +105,11 @@ int iscsi_allocate_thread_sets(u32 thread_pair_count)
ts->status = ISCSI_THREAD_SET_FREE; ts->status = ISCSI_THREAD_SET_FREE;
INIT_LIST_HEAD(&ts->ts_list); INIT_LIST_HEAD(&ts->ts_list);
spin_lock_init(&ts->ts_state_lock); 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->rx_restart_comp);
init_completion(&ts->tx_restart_comp); init_completion(&ts->tx_restart_comp);
init_completion(&ts->rx_start_comp); init_completion(&ts->rx_start_comp);
init_completion(&ts->tx_start_comp); init_completion(&ts->tx_start_comp);
sema_init(&ts->ts_activate_sem, 0);
ts->create_threads = 1; ts->create_threads = 1;
ts->tx_thread = kthread_run(iscsi_target_tx_thread, ts, "%s", 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; return allocated_thread_pair_count;
} }
static void iscsi_deallocate_thread_one(struct iscsi_thread_set *ts)
{
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);
kfree(ts);
}
void iscsi_deallocate_thread_sets(void) void iscsi_deallocate_thread_sets(void)
{ {
u32 released_count = 0;
struct iscsi_thread_set *ts = NULL; struct iscsi_thread_set *ts = NULL;
u32 released_count = 0;
while ((ts = iscsi_get_ts_from_inactive_list())) { while ((ts = iscsi_get_ts_from_inactive_list())) {
spin_lock_bh(&ts->ts_state_lock); iscsi_deallocate_thread_one(ts);
ts->status = ISCSI_THREAD_SET_DIE;
spin_unlock_bh(&ts->ts_state_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);
released_count++; released_count++;
kfree(ts);
} }
if (released_count) if (released_count)
@ -187,38 +195,13 @@ static void iscsi_deallocate_extra_thread_sets(void)
if (!ts) if (!ts)
break; break;
spin_lock_bh(&ts->ts_state_lock); iscsi_deallocate_thread_one(ts);
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);
released_count++; released_count++;
kfree(ts);
} }
if (released_count) { if (released_count)
pr_debug("Stopped %d thread set(s) (%d total threads)." pr_debug("Stopped %d thread set(s) (%d total threads)."
"\n", released_count, released_count * 2); "\n", released_count, released_count * 2);
}
} }
void iscsi_activate_thread_set(struct iscsi_conn *conn, struct iscsi_thread_set *ts) 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); spin_lock_bh(&ts->ts_state_lock);
conn->thread_set = ts; conn->thread_set = ts;
ts->conn = conn; ts->conn = conn;
ts->status = ISCSI_THREAD_SET_ACTIVE;
spin_unlock_bh(&ts->ts_state_lock); 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); 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) struct iscsi_thread_set *iscsi_get_thread_set(void)
@ -267,6 +249,7 @@ struct iscsi_thread_set *iscsi_get_thread_set(void)
ts->thread_count = 2; ts->thread_count = 2;
init_completion(&ts->rx_restart_comp); init_completion(&ts->rx_restart_comp);
init_completion(&ts->tx_restart_comp); init_completion(&ts->tx_restart_comp);
sema_init(&ts->ts_activate_sem, 0);
return ts; return ts;
} }
@ -452,18 +435,19 @@ struct iscsi_conn *iscsi_rx_thread_pre_handler(struct iscsi_thread_set *ts)
if (iscsi_signal_thread_pre_handler(ts) < 0) if (iscsi_signal_thread_pre_handler(ts) < 0)
return NULL; return NULL;
iscsi_check_to_add_additional_sets();
spin_lock_bh(&ts->ts_state_lock);
if (!ts->conn) { if (!ts->conn) {
pr_err("struct iscsi_thread_set->conn is NULL for" pr_err("struct iscsi_thread_set->conn is NULL for"
" thread_id: %d, going back to sleep\n", ts->thread_id); " RX thread_id: %s/%d\n", current->comm, current->pid);
goto sleep; 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; ts->thread_clear |= ISCSI_CLEAR_RX_THREAD;
complete(&ts->tx_start_comp); spin_unlock_bh(&ts->ts_state_lock);
wait_for_completion(&ts->tx_post_start_comp);
up(&ts->ts_activate_sem);
return ts->conn; return ts->conn;
} }
@ -505,27 +489,20 @@ struct iscsi_conn *iscsi_tx_thread_pre_handler(struct iscsi_thread_set *ts)
if (iscsi_signal_thread_pre_handler(ts) < 0) if (iscsi_signal_thread_pre_handler(ts) < 0)
return NULL; 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(); 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); 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); spin_unlock_bh(&ts->ts_state_lock);
up(&ts->ts_activate_sem);
return ts->conn; return ts->conn;
} }

5
drivers/target/iscsi/iscsi_target_tq.h
View file

@ -64,10 +64,6 @@ struct iscsi_thread_set {
struct iscsi_conn *conn; struct iscsi_conn *conn;
/* used for controlling ts state accesses */ /* used for controlling ts state accesses */
spinlock_t ts_state_lock; 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 */ /* used for restarting thread queue */
struct completion rx_restart_comp; struct completion rx_restart_comp;
/* used for restarting thread queue */ /* used for restarting thread queue */
@ -82,6 +78,7 @@ struct iscsi_thread_set {
struct task_struct *tx_thread; struct task_struct *tx_thread;
/* struct iscsi_thread_set in list list head*/ /* struct iscsi_thread_set in list list head*/
struct list_head ts_list; struct list_head ts_list;
struct semaphore ts_activate_sem;
}; };
#endif /*** ISCSI_THREAD_QUEUE_H ***/ #endif /*** ISCSI_THREAD_QUEUE_H ***/