+/* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
+ * vim:expandtab:shiftwidth=8:tabstop=8:
+ *
+ * Copyright (C) 2004 Cluster File Systems, Inc.
+ * Author: Jacob Berkman <jacob@clusterfs.com>
+ *
+ * This file is part of Lustre, http://www.lustre.org.
+ *
+ * Lustre is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ *
+ * Lustre is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Lustre; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#define DEBUG_SUBSYSTEM S_PORTALS
+
+#include <linux/kp30.h>
+#include <linux/libcfs.h>
+#include <linux/portals_compat25.h>
+
+
+
+struct lc_watchdog {
+ struct timer_list lcw_timer; /* kernel timer */
+ struct list_head lcw_list;
+ struct timeval lcw_last_touched;
+ struct task_struct *lcw_task;
+
+ void (*lcw_callback)(struct lc_watchdog *,
+ struct task_struct *,
+ void *data);
+ void *lcw_data;
+
+ int lcw_pid;
+ int lcw_time; /* time until watchdog fires, in ms */
+
+ enum {
+ LC_WATCHDOG_DISABLED,
+ LC_WATCHDOG_ENABLED,
+ LC_WATCHDOG_EXPIRED
+ } lcw_state;
+};
+
+/*
+ * The dispatcher will complete lcw_start_completion when it starts,
+ * and lcw_stop_completion when it exits.
+ * Wake lcw_event_waitq to signal timer callback dispatches.
+ */
+static struct completion lcw_start_completion;
+static struct completion lcw_stop_completion;
+static wait_queue_head_t lcw_event_waitq;
+
+/*
+ * Set this and wake lcw_event_waitq to stop the dispatcher.
+ */
+enum {
+ LCW_FLAG_STOP = 0
+};
+static unsigned long lcw_flags = 0;
+
+/*
+ * Number of outstanding watchdogs.
+ * When it hits 1, we start the dispatcher.
+ * When it hits 0, we stop the distpatcher.
+ */
+static __u32 lcw_refcount = 0;
+static DECLARE_MUTEX(lcw_refcount_sem);
+
+/*
+ * List of timers that have fired that need their callbacks run by the
+ * dispatcher.
+ */
+static spinlock_t lcw_pending_timers_lock = SPIN_LOCK_UNLOCKED;
+static struct list_head lcw_pending_timers = \
+ LIST_HEAD_INIT(lcw_pending_timers);
+
+static struct task_struct *lcw_lookup_task(struct lc_watchdog *lcw)
+{
+ struct task_struct *tsk;
+ unsigned long flags;
+ ENTRY;
+
+ read_lock_irqsave(&tasklist_lock, flags);
+ tsk = find_task_by_pid(lcw->lcw_pid);
+ read_unlock_irqrestore(&tasklist_lock, flags);
+ if (!tsk) {
+ CWARN("Process %d was not found in the task list; "
+ "watchdog callback may be incomplete\n", lcw->lcw_pid);
+ } else if (tsk != lcw->lcw_task) {
+ tsk = NULL;
+ CWARN("The current process %d did not set the watchdog; "
+ "watchdog callback may be incomplete\n", lcw->lcw_pid);
+ }
+
+ RETURN(tsk);
+}
+
+static void lcw_cb(unsigned long data)
+{
+ struct lc_watchdog *lcw = (struct lc_watchdog *)data;
+ struct task_struct *tsk;
+ unsigned long flags;
+
+ ENTRY;
+
+ if (lcw->lcw_state != LC_WATCHDOG_ENABLED) {
+ EXIT;
+ return;
+ }
+
+ lcw->lcw_state = LC_WATCHDOG_EXPIRED;
+
+ CWARN("Watchdog triggered for pid %d: it was inactive for %dus\n",
+ lcw->lcw_pid, (lcw->lcw_time * 1000) / HZ);
+
+ tsk = lcw_lookup_task(lcw);
+ if (tsk != NULL)
+ portals_debug_dumpstack(tsk);
+
+ spin_lock_irqsave(&lcw_pending_timers_lock, flags);
+ if (list_empty(&lcw->lcw_list)) {
+ list_add(&lcw->lcw_list, &lcw_pending_timers);
+ wake_up(&lcw_event_waitq);
+ }
+ spin_unlock_irqrestore(&lcw_pending_timers_lock, flags);
+
+ EXIT;
+}
+
+static int is_watchdog_fired(void)
+{
+ unsigned long flags;
+ int rc;
+
+ if (test_bit(LCW_FLAG_STOP, &lcw_flags))
+ return 1;
+
+ spin_lock_irqsave(&lcw_pending_timers_lock, flags);
+ rc = !list_empty(&lcw_pending_timers);
+ spin_unlock_irqrestore(&lcw_pending_timers_lock, flags);
+ return rc;
+}
+
+static int lcw_dispatch_main(void *data)
+{
+ int rc = 0;
+ unsigned long flags;
+ struct lc_watchdog *lcw;
+ struct task_struct *tsk;
+
+ ENTRY;
+
+ kportal_daemonize("lc_watchdogd");
+
+ SIGNAL_MASK_LOCK(current, flags);
+ sigfillset(¤t->blocked);
+ RECALC_SIGPENDING;
+ SIGNAL_MASK_UNLOCK(current, flags);
+
+ complete(&lcw_start_completion);
+
+ while (1) {
+ wait_event_interruptible(lcw_event_waitq, is_watchdog_fired());
+ CDEBUG(D_INFO, "Watchdog got woken up...\n");
+ if (test_bit(LCW_FLAG_STOP, &lcw_flags)) {
+ CDEBUG(D_INFO, "LCW_FLAG_STOP was set, shutting down...\n");
+
+ spin_lock_irqsave(&lcw_pending_timers_lock, flags);
+ rc = !list_empty(&lcw_pending_timers);
+ spin_unlock_irqrestore(&lcw_pending_timers_lock, flags);
+ if (rc) {
+ CERROR("pending timers list was not empty at "
+ "time of watchdog dispatch shutdown\n");
+ }
+ break;
+ }
+
+ spin_lock_irqsave(&lcw_pending_timers_lock, flags);
+ while (!list_empty(&lcw_pending_timers)) {
+
+ lcw = list_entry(lcw_pending_timers.next,
+ struct lc_watchdog,
+ lcw_list);
+ list_del_init(&lcw->lcw_list);
+ spin_unlock_irqrestore(&lcw_pending_timers_lock, flags);
+
+ CDEBUG(D_INFO, "found lcw for pid %d\n", lcw->lcw_pid);
+
+ if (lcw->lcw_state != LC_WATCHDOG_DISABLED) {
+ /*
+ * sanity check the task against our
+ * watchdog
+ */
+ tsk = lcw_lookup_task(lcw);
+ lcw->lcw_callback(lcw, tsk, lcw->lcw_data);
+ }
+
+ spin_lock_irqsave(&lcw_pending_timers_lock, flags);
+ }
+ spin_unlock_irqrestore(&lcw_pending_timers_lock, flags);
+ }
+
+ complete(&lcw_stop_completion);
+
+ RETURN(rc);
+}
+
+static void lcw_dispatch_start(void)
+{
+ int rc;
+
+ ENTRY;
+ LASSERT(lcw_refcount == 1);
+
+ init_completion(&lcw_stop_completion);
+ init_completion(&lcw_start_completion);
+ init_waitqueue_head(&lcw_event_waitq);
+
+ CDEBUG(D_INFO, "starting dispatch thread\n");
+ rc = kernel_thread(lcw_dispatch_main, NULL, 0);
+ if (rc < 0) {
+ CERROR("error spawning watchdog dispatch thread: %d\n", rc);
+ EXIT;
+ return;
+ }
+ wait_for_completion(&lcw_start_completion);
+ CDEBUG(D_INFO, "watchdog dispatcher initialization complete.\n");
+
+ EXIT;
+}
+
+static void lcw_dispatch_stop(void)
+{
+ ENTRY;
+ LASSERT(lcw_refcount == 0);
+
+ CDEBUG(D_INFO, "trying to stop watchdog dispatcher.\n");
+
+ set_bit(LCW_FLAG_STOP, &lcw_flags);
+ wake_up(&lcw_event_waitq);
+
+ wait_for_completion(&lcw_stop_completion);
+
+ CDEBUG(D_INFO, "watchdog dispatcher has shut down.\n");
+
+ EXIT;
+}
+
+struct lc_watchdog *lc_watchdog_add(int time,
+ void (*callback)(struct lc_watchdog *,
+ struct task_struct *,
+ void *),
+ void *data)
+{
+ struct lc_watchdog *lcw = NULL;
+ ENTRY;
+
+ PORTAL_ALLOC(lcw, sizeof(*lcw));
+ if (!lcw) {
+ CDEBUG(D_INFO, "Could not allocate new lc_watchdog\n");
+ RETURN(ERR_PTR(-ENOMEM));
+ }
+
+ lcw->lcw_task = current;
+ lcw->lcw_pid = current->pid;
+ lcw->lcw_time = (time * HZ) / 1000;
+ lcw->lcw_callback = callback ? callback : lc_watchdog_dumplog;
+ lcw->lcw_data = data;
+ lcw->lcw_state = LC_WATCHDOG_DISABLED;
+
+ INIT_LIST_HEAD(&lcw->lcw_list);
+
+ lcw->lcw_timer.function = lcw_cb;
+ lcw->lcw_timer.data = (unsigned long)lcw;
+ lcw->lcw_timer.expires = jiffies + lcw->lcw_time;
+ init_timer(&lcw->lcw_timer);
+
+ down(&lcw_refcount_sem);
+ if (++lcw_refcount == 1)
+ lcw_dispatch_start();
+ up(&lcw_refcount_sem);
+
+ /* Keep this working in case we enable them by default */
+ if (lcw->lcw_state == LC_WATCHDOG_ENABLED) {
+ do_gettimeofday(&lcw->lcw_last_touched);
+ add_timer(&lcw->lcw_timer);
+ }
+
+ RETURN(lcw);
+}
+EXPORT_SYMBOL(lc_watchdog_add);
+
+static long
+timeval_sub(struct timeval *large, struct timeval *small)
+{
+ return (large->tv_sec - small->tv_sec) * 1000000 +
+ (large->tv_usec - small->tv_usec);
+}
+
+static void lcw_update_time(struct lc_watchdog *lcw, const char *message)
+{
+ struct timeval newtime;
+ unsigned long timediff;
+
+ do_gettimeofday(&newtime);
+ if (lcw->lcw_state == LC_WATCHDOG_EXPIRED) {
+ timediff = timeval_sub(&newtime, &lcw->lcw_last_touched);
+ CWARN("Expired watchdog for pid %d %s after %lu.%.4lus\n",
+ lcw->lcw_pid,
+ message,
+ timediff / 1000000,
+ (timediff % 1000000) / 100);
+ }
+ lcw->lcw_last_touched = newtime;
+}
+
+void lc_watchdog_touch(struct lc_watchdog *lcw)
+{
+ unsigned long flags;
+ ENTRY;
+ LASSERT(lcw != NULL);
+
+ spin_lock_irqsave(&lcw_pending_timers_lock, flags);
+ if (!list_empty(&lcw->lcw_list))
+ list_del_init(&lcw->lcw_list);
+ spin_unlock_irqrestore(&lcw_pending_timers_lock, flags);
+
+ lcw_update_time(lcw, "touched");
+ lcw->lcw_state = LC_WATCHDOG_ENABLED;
+
+ mod_timer(&lcw->lcw_timer, jiffies + lcw->lcw_time);
+
+ EXIT;
+}
+EXPORT_SYMBOL(lc_watchdog_touch);
+
+void lc_watchdog_disable(struct lc_watchdog *lcw)
+{
+ unsigned long flags;
+ ENTRY;
+ LASSERT(lcw != NULL);
+
+ spin_lock_irqsave(&lcw_pending_timers_lock, flags);
+ if (!list_empty(&lcw->lcw_list))
+ list_del_init(&lcw->lcw_list);
+ spin_unlock_irqrestore(&lcw_pending_timers_lock, flags);
+
+ lcw_update_time(lcw, "disabled");
+ lcw->lcw_state = LC_WATCHDOG_DISABLED;
+
+ EXIT;
+}
+EXPORT_SYMBOL(lc_watchdog_disable);
+
+void lc_watchdog_delete(struct lc_watchdog *lcw)
+{
+ unsigned long flags;
+ ENTRY;
+ LASSERT(lcw != NULL);
+
+ del_timer(&lcw->lcw_timer);
+
+ lcw_update_time(lcw, "deleted");
+
+ spin_lock_irqsave(&lcw_pending_timers_lock, flags);
+ if (!list_empty(&lcw->lcw_list))
+ list_del_init(&lcw->lcw_list);
+ spin_unlock_irqrestore(&lcw_pending_timers_lock, flags);
+
+ down(&lcw_refcount_sem);
+ if (--lcw_refcount == 0)
+ lcw_dispatch_stop();
+ up(&lcw_refcount_sem);
+
+ PORTAL_FREE(lcw, sizeof(*lcw));
+
+ EXIT;
+}
+EXPORT_SYMBOL(lc_watchdog_delete);
+
+/*
+ * Provided watchdog handlers
+ */
+
+extern void portals_debug_dumplog_internal(void *arg);
+
+void lc_watchdog_dumplog(struct lc_watchdog *lcw,
+ struct task_struct *tsk,
+ void *data)
+{
+ tsk = tsk ? tsk : current;
+ portals_debug_dumplog_internal((void *)(long)tsk->pid);
+}
+EXPORT_SYMBOL(lc_watchdog_dumplog);
git://git.whamcloud.com / fs / lustre-release.git / commitdiff