diff options
Diffstat (limited to 'drivers/staging/lustre/lnet/libcfs/workitem.c')
| -rw-r--r-- | drivers/staging/lustre/lnet/libcfs/workitem.c | 469 |
1 files changed, 469 insertions, 0 deletions
diff --git a/drivers/staging/lustre/lnet/libcfs/workitem.c b/drivers/staging/lustre/lnet/libcfs/workitem.c new file mode 100644 index 000000000000..c72fe00dce8d --- /dev/null +++ b/drivers/staging/lustre/lnet/libcfs/workitem.c @@ -0,0 +1,469 @@ +/* + * 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. + * + * libcfs/libcfs/workitem.c + * + * Author: Isaac Huang <isaac@clusterfs.com> + * Liang Zhen <zhen.liang@sun.com> + */ + +#define DEBUG_SUBSYSTEM S_LNET + +#include "../../include/linux/libcfs/libcfs.h" + +#define CFS_WS_NAME_LEN 16 + +struct cfs_wi_sched { + /* chain on global list */ + struct list_head ws_list; + /** serialised workitems */ + spinlock_t ws_lock; + /** where schedulers sleep */ + wait_queue_head_t ws_waitq; + /** concurrent workitems */ + struct list_head ws_runq; + /** + * rescheduled running-workitems, a workitem can be rescheduled + * while running in wi_action(), but we don't to execute it again + * unless it returns from wi_action(), so we put it on ws_rerunq + * while rescheduling, and move it to runq after it returns + * from wi_action() + */ + struct list_head ws_rerunq; + /** CPT-table for this scheduler */ + struct cfs_cpt_table *ws_cptab; + /** CPT id for affinity */ + int ws_cpt; + /** number of scheduled workitems */ + int ws_nscheduled; + /** started scheduler thread, protected by cfs_wi_data::wi_glock */ + unsigned int ws_nthreads:30; + /** shutting down, protected by cfs_wi_data::wi_glock */ + unsigned int ws_stopping:1; + /** serialize starting thread, protected by cfs_wi_data::wi_glock */ + unsigned int ws_starting:1; + /** scheduler name */ + char ws_name[CFS_WS_NAME_LEN]; +}; + +static struct cfs_workitem_data { + /** serialize */ + spinlock_t wi_glock; + /** list of all schedulers */ + struct list_head wi_scheds; + /** WI module is initialized */ + int wi_init; + /** shutting down the whole WI module */ + int wi_stopping; +} cfs_wi_data; + +static inline int +cfs_wi_sched_cansleep(struct cfs_wi_sched *sched) +{ + spin_lock(&sched->ws_lock); + if (sched->ws_stopping) { + spin_unlock(&sched->ws_lock); + return 0; + } + + if (!list_empty(&sched->ws_runq)) { + spin_unlock(&sched->ws_lock); + return 0; + } + spin_unlock(&sched->ws_lock); + return 1; +} + +/* XXX: + * 0. it only works when called from wi->wi_action. + * 1. when it returns no one shall try to schedule the workitem. + */ +void +cfs_wi_exit(struct cfs_wi_sched *sched, cfs_workitem_t *wi) +{ + LASSERT(!in_interrupt()); /* because we use plain spinlock */ + LASSERT(!sched->ws_stopping); + + spin_lock(&sched->ws_lock); + + LASSERT(wi->wi_running); + if (wi->wi_scheduled) { /* cancel pending schedules */ + LASSERT(!list_empty(&wi->wi_list)); + list_del_init(&wi->wi_list); + + LASSERT(sched->ws_nscheduled > 0); + sched->ws_nscheduled--; + } + + LASSERT(list_empty(&wi->wi_list)); + + wi->wi_scheduled = 1; /* LBUG future schedule attempts */ + spin_unlock(&sched->ws_lock); +} +EXPORT_SYMBOL(cfs_wi_exit); + +/** + * cancel schedule request of workitem \a wi + */ +int +cfs_wi_deschedule(struct cfs_wi_sched *sched, cfs_workitem_t *wi) +{ + int rc; + + LASSERT(!in_interrupt()); /* because we use plain spinlock */ + LASSERT(!sched->ws_stopping); + + /* + * return 0 if it's running already, otherwise return 1, which + * means the workitem will not be scheduled and will not have + * any race with wi_action. + */ + spin_lock(&sched->ws_lock); + + rc = !(wi->wi_running); + + if (wi->wi_scheduled) { /* cancel pending schedules */ + LASSERT(!list_empty(&wi->wi_list)); + list_del_init(&wi->wi_list); + + LASSERT(sched->ws_nscheduled > 0); + sched->ws_nscheduled--; + + wi->wi_scheduled = 0; + } + + LASSERT(list_empty(&wi->wi_list)); + + spin_unlock(&sched->ws_lock); + return rc; +} +EXPORT_SYMBOL(cfs_wi_deschedule); + +/* + * Workitem scheduled with (serial == 1) is strictly serialised not only with + * itself, but also with others scheduled this way. + * + * Now there's only one static serialised queue, but in the future more might + * be added, and even dynamic creation of serialised queues might be supported. + */ +void +cfs_wi_schedule(struct cfs_wi_sched *sched, cfs_workitem_t *wi) +{ + LASSERT(!in_interrupt()); /* because we use plain spinlock */ + LASSERT(!sched->ws_stopping); + + spin_lock(&sched->ws_lock); + + if (!wi->wi_scheduled) { + LASSERT(list_empty(&wi->wi_list)); + + wi->wi_scheduled = 1; + sched->ws_nscheduled++; + if (!wi->wi_running) { + list_add_tail(&wi->wi_list, &sched->ws_runq); + wake_up(&sched->ws_waitq); + } else { + list_add(&wi->wi_list, &sched->ws_rerunq); + } + } + + LASSERT(!list_empty(&wi->wi_list)); + spin_unlock(&sched->ws_lock); +} +EXPORT_SYMBOL(cfs_wi_schedule); + +static int cfs_wi_scheduler(void *arg) +{ + struct cfs_wi_sched *sched = (struct cfs_wi_sched *)arg; + + cfs_block_allsigs(); + + /* CPT affinity scheduler? */ + if (sched->ws_cptab) + if (cfs_cpt_bind(sched->ws_cptab, sched->ws_cpt) != 0) + CWARN("Failed to bind %s on CPT %d\n", + sched->ws_name, sched->ws_cpt); + + spin_lock(&cfs_wi_data.wi_glock); + + LASSERT(sched->ws_starting == 1); + sched->ws_starting--; + sched->ws_nthreads++; + + spin_unlock(&cfs_wi_data.wi_glock); + + spin_lock(&sched->ws_lock); + + while (!sched->ws_stopping) { + int nloops = 0; + int rc; + cfs_workitem_t *wi; + + while (!list_empty(&sched->ws_runq) && + nloops < CFS_WI_RESCHED) { + wi = list_entry(sched->ws_runq.next, cfs_workitem_t, + wi_list); + LASSERT(wi->wi_scheduled && !wi->wi_running); + + list_del_init(&wi->wi_list); + + LASSERT(sched->ws_nscheduled > 0); + sched->ws_nscheduled--; + + wi->wi_running = 1; + wi->wi_scheduled = 0; + + spin_unlock(&sched->ws_lock); + nloops++; + + rc = (*wi->wi_action) (wi); + + spin_lock(&sched->ws_lock); + if (rc != 0) /* WI should be dead, even be freed! */ + continue; + + wi->wi_running = 0; + if (list_empty(&wi->wi_list)) + continue; + + LASSERT(wi->wi_scheduled); + /* wi is rescheduled, should be on rerunq now, we + * move it to runq so it can run action now + */ + list_move_tail(&wi->wi_list, &sched->ws_runq); + } + + if (!list_empty(&sched->ws_runq)) { + spin_unlock(&sched->ws_lock); + /* don't sleep because some workitems still + * expect me to come back soon + */ + cond_resched(); + spin_lock(&sched->ws_lock); + continue; + } + + spin_unlock(&sched->ws_lock); + rc = wait_event_interruptible_exclusive(sched->ws_waitq, + !cfs_wi_sched_cansleep(sched)); + spin_lock(&sched->ws_lock); + } + + spin_unlock(&sched->ws_lock); + + spin_lock(&cfs_wi_data.wi_glock); + sched->ws_nthreads--; + spin_unlock(&cfs_wi_data.wi_glock); + + return 0; +} + +void +cfs_wi_sched_destroy(struct cfs_wi_sched *sched) +{ + int i; + + LASSERT(cfs_wi_data.wi_init); + LASSERT(!cfs_wi_data.wi_stopping); + + spin_lock(&cfs_wi_data.wi_glock); + if (sched->ws_stopping) { + CDEBUG(D_INFO, "%s is in progress of stopping\n", + sched->ws_name); + spin_unlock(&cfs_wi_data.wi_glock); + return; + } + + LASSERT(!list_empty(&sched->ws_list)); + sched->ws_stopping = 1; + + spin_unlock(&cfs_wi_data.wi_glock); + + i = 2; + wake_up_all(&sched->ws_waitq); + + spin_lock(&cfs_wi_data.wi_glock); + while (sched->ws_nthreads > 0) { + CDEBUG(is_power_of_2(++i) ? D_WARNING : D_NET, + "waiting for %d threads of WI sched[%s] to terminate\n", + sched->ws_nthreads, sched->ws_name); + + spin_unlock(&cfs_wi_data.wi_glock); + set_current_state(TASK_UNINTERRUPTIBLE); + schedule_timeout(cfs_time_seconds(1) / 20); + spin_lock(&cfs_wi_data.wi_glock); + } + + list_del(&sched->ws_list); + + spin_unlock(&cfs_wi_data.wi_glock); + LASSERT(sched->ws_nscheduled == 0); + + LIBCFS_FREE(sched, sizeof(*sched)); +} +EXPORT_SYMBOL(cfs_wi_sched_destroy); + +int +cfs_wi_sched_create(char *name, struct cfs_cpt_table *cptab, + int cpt, int nthrs, struct cfs_wi_sched **sched_pp) +{ + struct cfs_wi_sched *sched; + int rc; + + LASSERT(cfs_wi_data.wi_init); + LASSERT(!cfs_wi_data.wi_stopping); + LASSERT(!cptab || cpt == CFS_CPT_ANY || + (cpt >= 0 && cpt < cfs_cpt_number(cptab))); + + LIBCFS_ALLOC(sched, sizeof(*sched)); + if (!sched) + return -ENOMEM; + + if (strlen(name) > sizeof(sched->ws_name) - 1) { + LIBCFS_FREE(sched, sizeof(*sched)); + return -E2BIG; + } + strncpy(sched->ws_name, name, sizeof(sched->ws_name)); + + sched->ws_cptab = cptab; + sched->ws_cpt = cpt; + + spin_lock_init(&sched->ws_lock); + init_waitqueue_head(&sched->ws_waitq); + INIT_LIST_HEAD(&sched->ws_runq); + INIT_LIST_HEAD(&sched->ws_rerunq); + INIT_LIST_HEAD(&sched->ws_list); + + rc = 0; + while (nthrs > 0) { + char name[16]; + struct task_struct *task; + + spin_lock(&cfs_wi_data.wi_glock); + while (sched->ws_starting > 0) { + spin_unlock(&cfs_wi_data.wi_glock); + schedule(); + spin_lock(&cfs_wi_data.wi_glock); + } + + sched->ws_starting++; + spin_unlock(&cfs_wi_data.wi_glock); + + if (sched->ws_cptab && sched->ws_cpt >= 0) { + snprintf(name, sizeof(name), "%s_%02d_%02u", + sched->ws_name, sched->ws_cpt, + sched->ws_nthreads); + } else { + snprintf(name, sizeof(name), "%s_%02u", + sched->ws_name, sched->ws_nthreads); + } + + task = kthread_run(cfs_wi_scheduler, sched, "%s", name); + if (!IS_ERR(task)) { + nthrs--; + continue; + } + rc = PTR_ERR(task); + + CERROR("Failed to create thread for WI scheduler %s: %d\n", + name, rc); + + spin_lock(&cfs_wi_data.wi_glock); + + /* make up for cfs_wi_sched_destroy */ + list_add(&sched->ws_list, &cfs_wi_data.wi_scheds); + sched->ws_starting--; + + spin_unlock(&cfs_wi_data.wi_glock); + + cfs_wi_sched_destroy(sched); + return rc; + } + spin_lock(&cfs_wi_data.wi_glock); + list_add(&sched->ws_list, &cfs_wi_data.wi_scheds); + spin_unlock(&cfs_wi_data.wi_glock); + + *sched_pp = sched; + return 0; +} +EXPORT_SYMBOL(cfs_wi_sched_create); + +int +cfs_wi_startup(void) +{ + memset(&cfs_wi_data, 0, sizeof(cfs_wi_data)); + + spin_lock_init(&cfs_wi_data.wi_glock); + INIT_LIST_HEAD(&cfs_wi_data.wi_scheds); + cfs_wi_data.wi_init = 1; + + return 0; +} + +void +cfs_wi_shutdown(void) +{ + struct cfs_wi_sched *sched; + struct cfs_wi_sched *temp; + + spin_lock(&cfs_wi_data.wi_glock); + cfs_wi_data.wi_stopping = 1; + spin_unlock(&cfs_wi_data.wi_glock); + + /* nobody should contend on this list */ + list_for_each_entry(sched, &cfs_wi_data.wi_scheds, ws_list) { + sched->ws_stopping = 1; + wake_up_all(&sched->ws_waitq); + } + + list_for_each_entry(sched, &cfs_wi_data.wi_scheds, ws_list) { + spin_lock(&cfs_wi_data.wi_glock); + + while (sched->ws_nthreads != 0) { + spin_unlock(&cfs_wi_data.wi_glock); + set_current_state(TASK_UNINTERRUPTIBLE); + schedule_timeout(cfs_time_seconds(1) / 20); + spin_lock(&cfs_wi_data.wi_glock); + } + spin_unlock(&cfs_wi_data.wi_glock); + } + list_for_each_entry_safe(sched, temp, &cfs_wi_data.wi_scheds, ws_list) { + list_del(&sched->ws_list); + LIBCFS_FREE(sched, sizeof(*sched)); + } + + cfs_wi_data.wi_stopping = 0; + cfs_wi_data.wi_init = 0; +} |