diff options
Diffstat (limited to 'drivers/staging/lustre/lnet/selftest/timer.c')
| -rw-r--r-- | drivers/staging/lustre/lnet/selftest/timer.c | 253 |
1 files changed, 253 insertions, 0 deletions
diff --git a/drivers/staging/lustre/lnet/selftest/timer.c b/drivers/staging/lustre/lnet/selftest/timer.c new file mode 100644 index 000000000000..2c078550277b --- /dev/null +++ b/drivers/staging/lustre/lnet/selftest/timer.c @@ -0,0 +1,253 @@ +/* + * GPL HEADER START + * + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 only, + * as published by the Free Software Foundation. + * + * This program 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 version 2 for more details (a copy is included + * in the LICENSE file that accompanied this code). + * + * You should have received a copy of the GNU General Public License + * version 2 along with this program; If not, see + * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf + * + * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, + * CA 95054 USA or visit www.sun.com if you need additional information or + * have any questions. + * + * GPL HEADER END + */ +/* + * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved. + * Use is subject to license terms. + * + * Copyright (c) 2011, 2012, Intel Corporation. + */ +/* + * This file is part of Lustre, http://www.lustre.org/ + * Lustre is a trademark of Sun Microsystems, Inc. + * + * lnet/selftest/timer.c + * + * Author: Isaac Huang <isaac@clusterfs.com> + */ + +#define DEBUG_SUBSYSTEM S_LNET + +#include "selftest.h" + + +/* + * Timers are implemented as a sorted queue of expiry times. The queue + * is slotted, with each slot holding timers which expire in a + * 2**STTIMER_MINPOLL (8) second period. The timers in each slot are + * sorted by increasing expiry time. The number of slots is 2**7 (128), + * to cover a time period of 1024 seconds into the future before wrapping. + */ +#define STTIMER_MINPOLL 3 /* log2 min poll interval (8 s) */ +#define STTIMER_SLOTTIME (1 << STTIMER_MINPOLL) +#define STTIMER_SLOTTIMEMASK (~(STTIMER_SLOTTIME - 1)) +#define STTIMER_NSLOTS (1 << 7) +#define STTIMER_SLOT(t) (&stt_data.stt_hash[(((t) >> STTIMER_MINPOLL) & \ + (STTIMER_NSLOTS - 1))]) + +struct st_timer_data { + spinlock_t stt_lock; + /* start time of the slot processed previously */ + cfs_time_t stt_prev_slot; + struct list_head stt_hash[STTIMER_NSLOTS]; + int stt_shuttingdown; + wait_queue_head_t stt_waitq; + int stt_nthreads; +} stt_data; + +void +stt_add_timer(stt_timer_t *timer) +{ + struct list_head *pos; + + spin_lock(&stt_data.stt_lock); + + LASSERT (stt_data.stt_nthreads > 0); + LASSERT (!stt_data.stt_shuttingdown); + LASSERT (timer->stt_func != NULL); + LASSERT (list_empty(&timer->stt_list)); + LASSERT (cfs_time_after(timer->stt_expires, cfs_time_current_sec())); + + /* a simple insertion sort */ + list_for_each_prev (pos, STTIMER_SLOT(timer->stt_expires)) { + stt_timer_t *old = list_entry(pos, stt_timer_t, stt_list); + + if (cfs_time_aftereq(timer->stt_expires, old->stt_expires)) + break; + } + list_add(&timer->stt_list, pos); + + spin_unlock(&stt_data.stt_lock); +} + +/* + * The function returns whether it has deactivated a pending timer or not. + * (ie. del_timer() of an inactive timer returns 0, del_timer() of an + * active timer returns 1.) + * + * CAVEAT EMPTOR: + * When 0 is returned, it is possible that timer->stt_func _is_ running on + * another CPU. + */ +int +stt_del_timer (stt_timer_t *timer) +{ + int ret = 0; + + spin_lock(&stt_data.stt_lock); + + LASSERT (stt_data.stt_nthreads > 0); + LASSERT (!stt_data.stt_shuttingdown); + + if (!list_empty(&timer->stt_list)) { + ret = 1; + list_del_init(&timer->stt_list); + } + + spin_unlock(&stt_data.stt_lock); + return ret; +} + +/* called with stt_data.stt_lock held */ +int +stt_expire_list (struct list_head *slot, cfs_time_t now) +{ + int expired = 0; + stt_timer_t *timer; + + while (!list_empty(slot)) { + timer = list_entry(slot->next, stt_timer_t, stt_list); + + if (cfs_time_after(timer->stt_expires, now)) + break; + + list_del_init(&timer->stt_list); + spin_unlock(&stt_data.stt_lock); + + expired++; + (*timer->stt_func) (timer->stt_data); + + spin_lock(&stt_data.stt_lock); + } + + return expired; +} + +int +stt_check_timers (cfs_time_t *last) +{ + int expired = 0; + cfs_time_t now; + cfs_time_t this_slot; + + now = cfs_time_current_sec(); + this_slot = now & STTIMER_SLOTTIMEMASK; + + spin_lock(&stt_data.stt_lock); + + while (cfs_time_aftereq(this_slot, *last)) { + expired += stt_expire_list(STTIMER_SLOT(this_slot), now); + this_slot = cfs_time_sub(this_slot, STTIMER_SLOTTIME); + } + + *last = now & STTIMER_SLOTTIMEMASK; + spin_unlock(&stt_data.stt_lock); + return expired; +} + + +int +stt_timer_main (void *arg) +{ + int rc = 0; + UNUSED(arg); + + SET_BUT_UNUSED(rc); + + cfs_block_allsigs(); + + while (!stt_data.stt_shuttingdown) { + stt_check_timers(&stt_data.stt_prev_slot); + + rc = wait_event_timeout(stt_data.stt_waitq, + stt_data.stt_shuttingdown, + cfs_time_seconds(STTIMER_SLOTTIME)); + } + + spin_lock(&stt_data.stt_lock); + stt_data.stt_nthreads--; + spin_unlock(&stt_data.stt_lock); + return 0; +} + +int +stt_start_timer_thread (void) +{ + task_t *task; + + LASSERT(!stt_data.stt_shuttingdown); + + task = kthread_run(stt_timer_main, NULL, "st_timer"); + if (IS_ERR(task)) + return PTR_ERR(task); + + spin_lock(&stt_data.stt_lock); + stt_data.stt_nthreads++; + spin_unlock(&stt_data.stt_lock); + return 0; +} + + +int +stt_startup (void) +{ + int rc = 0; + int i; + + stt_data.stt_shuttingdown = 0; + stt_data.stt_prev_slot = cfs_time_current_sec() & STTIMER_SLOTTIMEMASK; + + spin_lock_init(&stt_data.stt_lock); + for (i = 0; i < STTIMER_NSLOTS; i++) + INIT_LIST_HEAD(&stt_data.stt_hash[i]); + + stt_data.stt_nthreads = 0; + init_waitqueue_head(&stt_data.stt_waitq); + rc = stt_start_timer_thread(); + if (rc != 0) + CERROR ("Can't spawn timer thread: %d\n", rc); + + return rc; +} + +void +stt_shutdown (void) +{ + int i; + + spin_lock(&stt_data.stt_lock); + + for (i = 0; i < STTIMER_NSLOTS; i++) + LASSERT (list_empty(&stt_data.stt_hash[i])); + + stt_data.stt_shuttingdown = 1; + + wake_up(&stt_data.stt_waitq); + lst_wait_until(stt_data.stt_nthreads == 0, stt_data.stt_lock, + "waiting for %d threads to terminate\n", + stt_data.stt_nthreads); + + spin_unlock(&stt_data.stt_lock); +} |