staging: lustre: ptlrpc: use workqueue for pinger

lustre has a "Pinger" kthread which periodically pings peers
to ensure all hosts are functioning.

This can more easily be done using a work queue.

As maintaining contact with other peers is import for
keeping the filesystem running, and as the filesystem might
be involved in freeing memory, it is safest to have a
separate WQ_MEM_RECLAIM workqueue.

The SVC_EVENT functionality to wake up the thread can be
replaced with mod_delayed_work().

Also use round_jiffies_up_relative() rather than setting a
minimum of 1 second delay.  The PING_INTERVAL is measured in
seconds so this meets the need is allow the workqueue to
keep wakeups synchronized.

Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
NeilBrown 2018-03-02 10:31:25 +11:00 committed by Greg Kroah-Hartman
parent 236b4fcd5d
commit be3c64da24

View File

@ -217,21 +217,18 @@ static void ptlrpc_pinger_process_import(struct obd_import *imp,
}
}
static int ptlrpc_pinger_main(void *arg)
static struct workqueue_struct *pinger_wq;
static void ptlrpc_pinger_main(struct work_struct *ws);
static DECLARE_DELAYED_WORK(ping_work, ptlrpc_pinger_main);
static void ptlrpc_pinger_main(struct work_struct *ws)
{
struct ptlrpc_thread *thread = arg;
/* Record that the thread is running */
thread_set_flags(thread, SVC_RUNNING);
wake_up(&thread->t_ctl_waitq);
/* And now, loop forever, pinging as needed. */
while (1) {
unsigned long this_ping = cfs_time_current();
long time_to_next_wake;
struct timeout_item *item;
struct obd_import *imp;
unsigned long this_ping = cfs_time_current();
long time_to_next_wake;
struct timeout_item *item;
struct obd_import *imp;
do {
mutex_lock(&pinger_mutex);
list_for_each_entry(item, &timeout_list, ti_chain) {
item->ti_cb(item, item->ti_cb_data);
@ -260,50 +257,24 @@ static int ptlrpc_pinger_main(void *arg)
time_to_next_wake,
cfs_time_add(this_ping,
PING_INTERVAL * HZ));
if (time_to_next_wake > 0) {
wait_event_idle_timeout(thread->t_ctl_waitq,
thread_is_stopping(thread) ||
thread_is_event(thread),
max_t(long, time_to_next_wake, HZ));
if (thread_test_and_clear_flags(thread, SVC_STOPPING))
break;
/* woken after adding import to reset timer */
thread_test_and_clear_flags(thread, SVC_EVENT);
}
}
} while (time_to_next_wake <= 0);
thread_set_flags(thread, SVC_STOPPED);
wake_up(&thread->t_ctl_waitq);
CDEBUG(D_NET, "pinger thread exiting, process %d\n", current_pid());
return 0;
queue_delayed_work(pinger_wq, &ping_work,
round_jiffies_up_relative(time_to_next_wake));
}
static struct ptlrpc_thread pinger_thread;
int ptlrpc_start_pinger(void)
{
struct task_struct *task;
int rc;
if (!thread_is_init(&pinger_thread) &&
!thread_is_stopped(&pinger_thread))
if (pinger_wq)
return -EALREADY;
init_waitqueue_head(&pinger_thread.t_ctl_waitq);
strcpy(pinger_thread.t_name, "ll_ping");
task = kthread_run(ptlrpc_pinger_main, &pinger_thread,
pinger_thread.t_name);
if (IS_ERR(task)) {
rc = PTR_ERR(task);
CERROR("cannot start pinger thread: rc = %d\n", rc);
return rc;
pinger_wq = alloc_workqueue("ptlrpc_pinger", WQ_MEM_RECLAIM, 1);
if (!pinger_wq) {
CERROR("cannot start pinger workqueue\n");
return -ENOMEM;
}
wait_event_idle(pinger_thread.t_ctl_waitq,
thread_is_running(&pinger_thread));
queue_delayed_work(pinger_wq, &ping_work, 0);
return 0;
}
@ -313,16 +284,13 @@ int ptlrpc_stop_pinger(void)
{
int rc = 0;
if (thread_is_init(&pinger_thread) ||
thread_is_stopped(&pinger_thread))
if (!pinger_wq)
return -EALREADY;
ptlrpc_pinger_remove_timeouts();
thread_set_flags(&pinger_thread, SVC_STOPPING);
wake_up(&pinger_thread.t_ctl_waitq);
wait_event_idle(pinger_thread.t_ctl_waitq,
thread_is_stopped(&pinger_thread));
cancel_delayed_work_sync(&ping_work);
destroy_workqueue(pinger_wq);
pinger_wq = NULL;
return rc;
}
@ -505,6 +473,5 @@ static int ptlrpc_pinger_remove_timeouts(void)
void ptlrpc_pinger_wake_up(void)
{
thread_add_flags(&pinger_thread, SVC_EVENT);
wake_up(&pinger_thread.t_ctl_waitq);
mod_delayed_work(pinger_wq, &ping_work, 0);
}