[PATCH 10/17] staging: lustre: ptlrpc: use delayed_work in sec_gc

From: NeilBrown
Date: Thu Mar 01 2018 - 18:33:37 EST


The garbage collection for security contexts currently
has a dedicated kthread which wakes up every 30 minutes
to discard old garbage.

Replace this with a simple delayed_work item on the
system work queue.

Signed-off-by: NeilBrown <neilb@xxxxxxxx>
---
drivers/staging/lustre/lustre/ptlrpc/sec_gc.c | 90 ++++++++-----------------
1 file changed, 28 insertions(+), 62 deletions(-)

diff --git a/drivers/staging/lustre/lustre/ptlrpc/sec_gc.c b/drivers/staging/lustre/lustre/ptlrpc/sec_gc.c
index 48f1a72afd77..2c8bad7b7877 100644
--- a/drivers/staging/lustre/lustre/ptlrpc/sec_gc.c
+++ b/drivers/staging/lustre/lustre/ptlrpc/sec_gc.c
@@ -55,7 +55,6 @@ static spinlock_t sec_gc_list_lock;
static LIST_HEAD(sec_gc_ctx_list);
static spinlock_t sec_gc_ctx_list_lock;

-static struct ptlrpc_thread sec_gc_thread;
static atomic_t sec_gc_wait_del = ATOMIC_INIT(0);

void sptlrpc_gc_add_sec(struct ptlrpc_sec *sec)
@@ -139,86 +138,53 @@ static void sec_do_gc(struct ptlrpc_sec *sec)
sec->ps_gc_next = ktime_get_real_seconds() + sec->ps_gc_interval;
}

-static int sec_gc_main(void *arg)
-{
- struct ptlrpc_thread *thread = arg;
-
- unshare_fs_struct();
+static void sec_gc_main(struct work_struct *ws);
+static DECLARE_DELAYED_WORK(sec_gc_work, sec_gc_main);

- /* Record that the thread is running */
- thread_set_flags(thread, SVC_RUNNING);
- wake_up(&thread->t_ctl_waitq);
-
- while (1) {
- struct ptlrpc_sec *sec;
+static void sec_gc_main(struct work_struct *ws)
+{
+ struct ptlrpc_sec *sec;

- sec_process_ctx_list();
+ sec_process_ctx_list();
again:
- /* go through sec list do gc.
- * FIXME here we iterate through the whole list each time which
- * is not optimal. we perhaps want to use balanced binary tree
- * to trace each sec as order of expiry time.
- * another issue here is we wakeup as fixed interval instead of
- * according to each sec's expiry time
+ /* go through sec list do gc.
+ * FIXME here we iterate through the whole list each time which
+ * is not optimal. we perhaps want to use balanced binary tree
+ * to trace each sec as order of expiry time.
+ * another issue here is we wakeup as fixed interval instead of
+ * according to each sec's expiry time
+ */
+ mutex_lock(&sec_gc_mutex);
+ list_for_each_entry(sec, &sec_gc_list, ps_gc_list) {
+ /* if someone is waiting to be deleted, let it
+ * proceed as soon as possible.
*/
- mutex_lock(&sec_gc_mutex);
- list_for_each_entry(sec, &sec_gc_list, ps_gc_list) {
- /* if someone is waiting to be deleted, let it
- * proceed as soon as possible.
- */
- if (atomic_read(&sec_gc_wait_del)) {
- CDEBUG(D_SEC, "deletion pending, start over\n");
- mutex_unlock(&sec_gc_mutex);
- goto again;
- }
-
- sec_do_gc(sec);
+ if (atomic_read(&sec_gc_wait_del)) {
+ CDEBUG(D_SEC, "deletion pending, start over\n");
+ mutex_unlock(&sec_gc_mutex);
+ goto again;
}
- mutex_unlock(&sec_gc_mutex);
-
- /* check ctx list again before sleep */
- sec_process_ctx_list();
- wait_event_idle_timeout(thread->t_ctl_waitq,
- thread_is_stopping(thread),
- SEC_GC_INTERVAL * HZ);

- if (thread_test_and_clear_flags(thread, SVC_STOPPING))
- break;
+ sec_do_gc(sec);
}
+ mutex_unlock(&sec_gc_mutex);

- thread_set_flags(thread, SVC_STOPPED);
- wake_up(&thread->t_ctl_waitq);
- return 0;
+ /* check ctx list again before sleep */
+ sec_process_ctx_list();
+ schedule_delayed_work(&sec_gc_work, SEC_GC_INTERVAL * HZ);
}

int sptlrpc_gc_init(void)
{
- struct task_struct *task;
-
mutex_init(&sec_gc_mutex);
spin_lock_init(&sec_gc_list_lock);
spin_lock_init(&sec_gc_ctx_list_lock);

- /* initialize thread control */
- memset(&sec_gc_thread, 0, sizeof(sec_gc_thread));
- init_waitqueue_head(&sec_gc_thread.t_ctl_waitq);
-
- task = kthread_run(sec_gc_main, &sec_gc_thread, "sptlrpc_gc");
- if (IS_ERR(task)) {
- CERROR("can't start gc thread: %ld\n", PTR_ERR(task));
- return PTR_ERR(task);
- }
-
- wait_event_idle(sec_gc_thread.t_ctl_waitq,
- thread_is_running(&sec_gc_thread));
+ schedule_delayed_work(&sec_gc_work, 0);
return 0;
}

void sptlrpc_gc_fini(void)
{
- thread_set_flags(&sec_gc_thread, SVC_STOPPING);
- wake_up(&sec_gc_thread.t_ctl_waitq);
-
- wait_event_idle(sec_gc_thread.t_ctl_waitq,
- thread_is_stopped(&sec_gc_thread));
+ cancel_delayed_work_sync(&sec_gc_work);
}