X-Git-Url: https://gerrit.opnfv.org/gerrit/gitweb?a=blobdiff_plain;f=kernel%2Fdrivers%2Fstaging%2Flustre%2Flustre%2Flibcfs%2Fworkitem.c;fp=kernel%2Fdrivers%2Fstaging%2Flustre%2Flustre%2Flibcfs%2Fworkitem.c;h=48009b7758456acae626aa1ae576acea5c20078d;hb=9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00;hp=0000000000000000000000000000000000000000;hpb=98260f3884f4a202f9ca5eabed40b1354c489b29;p=kvmfornfv.git

diff --git a/kernel/drivers/staging/lustre/lustre/libcfs/workitem.c b/kernel/drivers/staging/lustre/lustre/libcfs/workitem.c
new file mode 100644
index 000000000..48009b775
--- /dev/null
+++ b/kernel/drivers/staging/lustre/lustre/libcfs/workitem.c
@@ -0,0 +1,479 @@
+/*
+ * 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
+
+typedef struct cfs_wi_sched {
+	struct list_head		ws_list;	/* chain on global 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];
+} cfs_wi_sched_t;
+
+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 void
+cfs_wi_sched_lock(cfs_wi_sched_t *sched)
+{
+	spin_lock(&sched->ws_lock);
+}
+
+static inline void
+cfs_wi_sched_unlock(cfs_wi_sched_t *sched)
+{
+	spin_unlock(&sched->ws_lock);
+}
+
+static inline int
+cfs_wi_sched_cansleep(cfs_wi_sched_t *sched)
+{
+	cfs_wi_sched_lock(sched);
+	if (sched->ws_stopping) {
+		cfs_wi_sched_unlock(sched);
+		return 0;
+	}
+
+	if (!list_empty(&sched->ws_runq)) {
+		cfs_wi_sched_unlock(sched);
+		return 0;
+	}
+	cfs_wi_sched_unlock(sched);
+	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);
+
+	cfs_wi_sched_lock(sched);
+
+	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 */
+	cfs_wi_sched_unlock(sched);
+
+	return;
+}
+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.
+	 */
+	cfs_wi_sched_lock(sched);
+
+	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));
+
+	cfs_wi_sched_unlock(sched);
+	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);
+
+	cfs_wi_sched_lock(sched);
+
+	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));
+	cfs_wi_sched_unlock(sched);
+	return;
+}
+EXPORT_SYMBOL(cfs_wi_schedule);
+
+
+static int
+cfs_wi_scheduler (void *arg)
+{
+	struct cfs_wi_sched	*sched = (cfs_wi_sched_t *)arg;
+
+	cfs_block_allsigs();
+
+	/* CPT affinity scheduler? */
+	if (sched->ws_cptab != NULL)
+		cfs_cpt_bind(sched->ws_cptab, 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);
+
+	cfs_wi_sched_lock(sched);
+
+	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;
+
+
+			cfs_wi_sched_unlock(sched);
+			nloops++;
+
+			rc = (*wi->wi_action) (wi);
+
+			cfs_wi_sched_lock(sched);
+			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)) {
+			cfs_wi_sched_unlock(sched);
+			/* don't sleep because some workitems still
+			 * expect me to come back soon */
+			cond_resched();
+			cfs_wi_sched_lock(sched);
+			continue;
+		}
+
+		cfs_wi_sched_unlock(sched);
+		rc = wait_event_interruptible_exclusive(sched->ws_waitq,
+						!cfs_wi_sched_cansleep(sched));
+		cfs_wi_sched_lock(sched);
+	}
+
+	cfs_wi_sched_unlock(sched);
+
+	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_PO2(++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 == NULL || cpt == CFS_CPT_ANY ||
+		(cpt >= 0 && cpt < cfs_cpt_number(cptab)));
+
+	LIBCFS_ALLOC(sched, sizeof(*sched));
+	if (sched == NULL)
+		return -ENOMEM;
+
+	strncpy(sched->ws_name, name, CFS_WS_NAME_LEN);
+	sched->ws_name[CFS_WS_NAME_LEN - 1] = '\0';
+	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 != NULL && 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;
+
+	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);
+	}
+	while (!list_empty(&cfs_wi_data.wi_scheds)) {
+		sched = list_entry(cfs_wi_data.wi_scheds.next,
+				       struct cfs_wi_sched, ws_list);
+		list_del(&sched->ws_list);
+		LIBCFS_FREE(sched, sizeof(*sched));
+	}
+
+	cfs_wi_data.wi_stopping = 0;
+	cfs_wi_data.wi_init = 0;
+}