-/* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
- * vim:expandtab:shiftwidth=8:tabstop=8:
- *
+/*
* GPL HEADER START
*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
* GPL HEADER END
*/
/*
- * Copyright 2008 Sun Microsystems, Inc. All rights reserved
+ * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
* Use is subject to license terms.
*/
/*
#include "tracefile.h"
struct lc_watchdog {
- cfs_timer_t lcw_timer; /* kernel timer */
- cfs_list_t lcw_list;
- cfs_time_t lcw_last_touched;
- cfs_task_t *lcw_task;
-
- void (*lcw_callback)(pid_t, void *);
- void *lcw_data;
+ cfs_spinlock_t lcw_lock; /* check or change lcw_list */
+ int lcw_refcount; /* must hold lcw_pending_timers_lock */
+ cfs_timer_t lcw_timer; /* kernel timer */
+ cfs_list_t lcw_list; /* chain on pending list */
+ cfs_time_t lcw_last_touched; /* last touched stamp */
+ cfs_task_t *lcw_task; /* owner task */
+ void (*lcw_callback)(pid_t, void *);
+ void *lcw_data;
- pid_t lcw_pid;
+ pid_t lcw_pid;
enum {
LC_WATCHDOG_DISABLED,
/*
* Number of outstanding watchdogs.
* When it hits 1, we start the dispatcher.
- * When it hits 0, we stop the distpatcher.
+ * When it hits 0, we stop the dispatcher.
*/
static __u32 lcw_refcount = 0;
-static CFS_DECLARE_MUTEX(lcw_refcount_sem);
+static CFS_DEFINE_MUTEX(lcw_refcount_mutex);
/*
* List of timers that have fired that need their callbacks run by the
* dispatcher.
*/
/* BH lock! */
-static cfs_spinlock_t lcw_pending_timers_lock = CFS_SPIN_LOCK_UNLOCKED;
-static cfs_list_t lcw_pending_timers = \
- CFS_LIST_HEAD_INIT(lcw_pending_timers);
+static DEFINE_SPINLOCK(lcw_pending_timers_lock);
+static cfs_list_t lcw_pending_timers = CFS_LIST_HEAD_INIT(lcw_pending_timers);
/* Last time a watchdog expired */
static cfs_time_t lcw_last_watchdog_time;
static int lcw_recent_watchdog_count;
-static cfs_spinlock_t lcw_last_watchdog_lock = CFS_SPIN_LOCK_UNLOCKED;
static void
lcw_dump(struct lc_watchdog *lcw)
ENTRY;
#if defined(HAVE_TASKLIST_LOCK)
cfs_read_lock(&tasklist_lock);
-#elif defined(HAVE_TASK_RCU)
- rcu_read_lock();
#else
- CERROR("unable to dump stack because of missing export\n");
- RETURN_EXIT;
+ rcu_read_lock();
#endif
- if (lcw->lcw_task == NULL) {
+ if (lcw->lcw_task == NULL) {
LCONSOLE_WARN("Process " LPPID " was not found in the task "
"list; watchdog callback may be incomplete\n",
(int)lcw->lcw_pid);
#if defined(HAVE_TASKLIST_LOCK)
cfs_read_unlock(&tasklist_lock);
-#elif defined(HAVE_TASK_RCU)
+#else
rcu_read_unlock();
#endif
EXIT;
static void lcw_cb(ulong_ptr_t data)
{
struct lc_watchdog *lcw = (struct lc_watchdog *)data;
- cfs_time_t current_time;
- cfs_duration_t delta_time;
- struct timeval timediff;
-
ENTRY;
if (lcw->lcw_state != LC_WATCHDOG_ENABLED) {
}
lcw->lcw_state = LC_WATCHDOG_EXPIRED;
- current_time = cfs_time_current();
+ cfs_spin_lock_bh(&lcw->lcw_lock);
+ LASSERT(cfs_list_empty(&lcw->lcw_list));
+
+ cfs_spin_lock_bh(&lcw_pending_timers_lock);
+ lcw->lcw_refcount++; /* +1 for pending list */
+ cfs_list_add(&lcw->lcw_list, &lcw_pending_timers);
+ cfs_waitq_signal(&lcw_event_waitq);
+
+ cfs_spin_unlock_bh(&lcw_pending_timers_lock);
+ cfs_spin_unlock_bh(&lcw->lcw_lock);
+ EXIT;
+}
+
+static int is_watchdog_fired(void)
+{
+ int rc;
+
+ if (cfs_test_bit(LCW_FLAG_STOP, &lcw_flags))
+ return 1;
+
+ cfs_spin_lock_bh(&lcw_pending_timers_lock);
+ rc = !cfs_list_empty(&lcw_pending_timers);
+ cfs_spin_unlock_bh(&lcw_pending_timers_lock);
+ return rc;
+}
+
+static void lcw_dump_stack(struct lc_watchdog *lcw)
+{
+ cfs_time_t current_time;
+ cfs_duration_t delta_time;
+ struct timeval timediff;
+
+ current_time = cfs_time_current();
delta_time = cfs_time_sub(current_time, lcw->lcw_last_touched);
cfs_duration_usec(delta_time, &timediff);
- /* Check to see if we should throttle the watchdog timer to avoid
+ /*
+ * Check to see if we should throttle the watchdog timer to avoid
* too many dumps going to the console thus triggering an NMI.
- * Normally we would not hold the spin lock over the CWARN but in
- * this case we hold it to ensure non ratelimited lcw_dumps are not
- * interleaved on the console making them hard to read. */
- cfs_spin_lock_bh(&lcw_last_watchdog_lock);
+ */
delta_time = cfs_duration_sec(cfs_time_sub(current_time,
lcw_last_watchdog_time));
lcw_recent_watchdog_count = 0;
}
- /* This warning should appear on the console, but may not get
- * into the logs since we're running in a softirq handler */
LCONSOLE_WARN("Service thread pid %u was inactive for "
"%lu.%.02lus. The thread might be hung, or it "
"might only be slow and will resume later. "
timediff.tv_sec,
timediff.tv_usec / 10000);
lcw_dump(lcw);
- }
-
- cfs_spin_unlock_bh(&lcw_last_watchdog_lock);
- cfs_spin_lock_bh(&lcw_pending_timers_lock);
-
- if (cfs_list_empty(&lcw->lcw_list)) {
- cfs_list_add(&lcw->lcw_list, &lcw_pending_timers);
- cfs_waitq_signal(&lcw_event_waitq);
}
-
- cfs_spin_unlock_bh(&lcw_pending_timers_lock);
-
- EXIT;
-}
-
-static int is_watchdog_fired(void)
-{
- int rc;
-
- if (cfs_test_bit(LCW_FLAG_STOP, &lcw_flags))
- return 1;
-
- cfs_spin_lock_bh(&lcw_pending_timers_lock);
- rc = !cfs_list_empty(&lcw_pending_timers);
- cfs_spin_unlock_bh(&lcw_pending_timers_lock);
- return rc;
}
static int lcw_dispatch_main(void *data)
int rc = 0;
unsigned long flags;
struct lc_watchdog *lcw;
+ CFS_LIST_HEAD (zombies);
ENTRY;
cfs_complete(&lcw_start_completion);
while (1) {
+ int dumplog = 1;
+
cfs_wait_event_interruptible(lcw_event_waitq,
is_watchdog_fired(), rc);
CDEBUG(D_INFO, "Watchdog got woken up...\n");
cfs_spin_lock_bh(&lcw_pending_timers_lock);
while (!cfs_list_empty(&lcw_pending_timers)) {
+ int is_dumplog;
lcw = cfs_list_entry(lcw_pending_timers.next,
- struct lc_watchdog,
- lcw_list);
+ struct lc_watchdog, lcw_list);
+ /* +1 ref for callback to make sure lwc wouldn't be
+ * deleted after releasing lcw_pending_timers_lock */
+ lcw->lcw_refcount++;
+ cfs_spin_unlock_bh(&lcw_pending_timers_lock);
+
+ /* lock ordering */
+ cfs_spin_lock_bh(&lcw->lcw_lock);
+ cfs_spin_lock_bh(&lcw_pending_timers_lock);
+
+ if (cfs_list_empty(&lcw->lcw_list)) {
+ /* already removed from pending list */
+ lcw->lcw_refcount--; /* -1 ref for callback */
+ if (lcw->lcw_refcount == 0)
+ cfs_list_add(&lcw->lcw_list, &zombies);
+ cfs_spin_unlock_bh(&lcw->lcw_lock);
+ /* still hold lcw_pending_timers_lock */
+ continue;
+ }
+
cfs_list_del_init(&lcw->lcw_list);
+ lcw->lcw_refcount--; /* -1 ref for pending list */
+
cfs_spin_unlock_bh(&lcw_pending_timers_lock);
+ cfs_spin_unlock_bh(&lcw->lcw_lock);
- CDEBUG(D_INFO, "found lcw for pid " LPPID "\n", lcw->lcw_pid);
+ CDEBUG(D_INFO, "found lcw for pid " LPPID "\n",
+ lcw->lcw_pid);
+ lcw_dump_stack(lcw);
- if (lcw->lcw_state != LC_WATCHDOG_DISABLED)
+ is_dumplog = lcw->lcw_callback == lc_watchdog_dumplog;
+ if (lcw->lcw_state != LC_WATCHDOG_DISABLED &&
+ (dumplog || !is_dumplog)) {
lcw->lcw_callback(lcw->lcw_pid, lcw->lcw_data);
+ if (dumplog && is_dumplog)
+ dumplog = 0;
+ }
cfs_spin_lock_bh(&lcw_pending_timers_lock);
+ lcw->lcw_refcount--; /* -1 ref for callback */
+ if (lcw->lcw_refcount == 0)
+ cfs_list_add(&lcw->lcw_list, &zombies);
}
cfs_spin_unlock_bh(&lcw_pending_timers_lock);
+
+ while (!cfs_list_empty(&zombies)) {
+ lcw = cfs_list_entry(lcw_pending_timers.next,
+ struct lc_watchdog, lcw_list);
+ cfs_list_del(&lcw->lcw_list);
+ LIBCFS_FREE(lcw, sizeof(*lcw));
+ }
}
cfs_complete(&lcw_stop_completion);
cfs_waitq_init(&lcw_event_waitq);
CDEBUG(D_INFO, "starting dispatch thread\n");
- rc = cfs_kernel_thread(lcw_dispatch_main, NULL, 0);
+ rc = cfs_create_thread(lcw_dispatch_main, NULL, 0);
if (rc < 0) {
CERROR("error spawning watchdog dispatch thread: %d\n", rc);
EXIT;
RETURN(ERR_PTR(-ENOMEM));
}
+ cfs_spin_lock_init(&lcw->lcw_lock);
+ lcw->lcw_refcount = 1; /* refcount for owner */
lcw->lcw_task = cfs_current();
lcw->lcw_pid = cfs_curproc_pid();
lcw->lcw_callback = (callback != NULL) ? callback : lc_watchdog_dumplog;
CFS_INIT_LIST_HEAD(&lcw->lcw_list);
cfs_timer_init(&lcw->lcw_timer, lcw_cb, lcw);
- cfs_down(&lcw_refcount_sem);
+ cfs_mutex_lock(&lcw_refcount_mutex);
if (++lcw_refcount == 1)
lcw_dispatch_start();
- cfs_up(&lcw_refcount_sem);
+ cfs_mutex_unlock(&lcw_refcount_mutex);
/* Keep this working in case we enable them by default */
if (lcw->lcw_state == LC_WATCHDOG_ENABLED) {
lcw->lcw_last_touched = newtime;
}
+static void lc_watchdog_del_pending(struct lc_watchdog *lcw)
+{
+ cfs_spin_lock_bh(&lcw->lcw_lock);
+ if (unlikely(!cfs_list_empty(&lcw->lcw_list))) {
+ cfs_spin_lock_bh(&lcw_pending_timers_lock);
+ cfs_list_del_init(&lcw->lcw_list);
+ lcw->lcw_refcount--; /* -1 ref for pending list */
+ cfs_spin_unlock_bh(&lcw_pending_timers_lock);
+ }
+
+ cfs_spin_unlock_bh(&lcw->lcw_lock);
+}
+
void lc_watchdog_touch(struct lc_watchdog *lcw, int timeout)
{
ENTRY;
LASSERT(lcw != NULL);
- cfs_spin_lock_bh(&lcw_pending_timers_lock);
- cfs_list_del_init(&lcw->lcw_list);
- cfs_spin_unlock_bh(&lcw_pending_timers_lock);
+ lc_watchdog_del_pending(lcw);
lcw_update_time(lcw, "resumed");
lcw->lcw_state = LC_WATCHDOG_ENABLED;
ENTRY;
LASSERT(lcw != NULL);
- cfs_spin_lock_bh(&lcw_pending_timers_lock);
- if (!cfs_list_empty(&lcw->lcw_list))
- cfs_list_del_init(&lcw->lcw_list);
- cfs_spin_unlock_bh(&lcw_pending_timers_lock);
+ lc_watchdog_del_pending(lcw);
lcw_update_time(lcw, "completed");
lcw->lcw_state = LC_WATCHDOG_DISABLED;
void lc_watchdog_delete(struct lc_watchdog *lcw)
{
+ int dead;
+
ENTRY;
LASSERT(lcw != NULL);
lcw_update_time(lcw, "stopped");
+ cfs_spin_lock_bh(&lcw->lcw_lock);
cfs_spin_lock_bh(&lcw_pending_timers_lock);
- if (!cfs_list_empty(&lcw->lcw_list))
+ if (unlikely(!cfs_list_empty(&lcw->lcw_list))) {
cfs_list_del_init(&lcw->lcw_list);
+ lcw->lcw_refcount--; /* -1 ref for pending list */
+ }
+
+ lcw->lcw_refcount--; /* -1 ref for owner */
+ dead = lcw->lcw_refcount == 0;
cfs_spin_unlock_bh(&lcw_pending_timers_lock);
+ cfs_spin_unlock_bh(&lcw->lcw_lock);
- cfs_down(&lcw_refcount_sem);
+ if (dead)
+ LIBCFS_FREE(lcw, sizeof(*lcw));
+
+ cfs_mutex_lock(&lcw_refcount_mutex);
if (--lcw_refcount == 0)
lcw_dispatch_stop();
- cfs_up(&lcw_refcount_sem);
-
- LIBCFS_FREE(lcw, sizeof(*lcw));
+ cfs_mutex_unlock(&lcw_refcount_mutex);
EXIT;
}
git://git.whamcloud.com / fs / lustre-release.git / blobdiff