Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / drivers / staging / lustre / include / linux / libcfs / libcfs_workitem.h

diff --git a/kernel/drivers/staging/lustre/include/linux/libcfs/libcfs_workitem.h b/kernel/drivers/staging/lustre/include/linux/libcfs/libcfs_workitem.h
new file mode 100644 (file)
index 0000000..5cc64f3
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+++ b/kernel/drivers/staging/lustre/include/linux/libcfs/libcfs_workitem.h
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+/*
+ * 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) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Use is subject to license terms.
+ *
+ * Copyright (c) 2012, Intel Corporation.
+ */
+/*
+ * This file is part of Lustre, http://www.lustre.org/
+ * Lustre is a trademark of Sun Microsystems, Inc.
+ *
+ * libcfs/include/libcfs/libcfs_workitem.h
+ *
+ * Author: Isaac Huang  <he.h.huang@oracle.com>
+ *      Liang Zhen   <zhen.liang@sun.com>
+ *
+ * A workitems is deferred work with these semantics:
+ * - a workitem always runs in thread context.
+ * - a workitem can be concurrent with other workitems but is strictly
+ *   serialized with respect to itself.
+ * - no CPU affinity, a workitem does not necessarily run on the same CPU
+ *   that schedules it. However, this might change in the future.
+ * - if a workitem is scheduled again before it has a chance to run, it
+ *   runs only once.
+ * - if a workitem is scheduled while it runs, it runs again after it
+ *   completes; this ensures that events occurring while other events are
+ *   being processed receive due attention. This behavior also allows a
+ *   workitem to reschedule itself.
+ *
+ * Usage notes:
+ * - a workitem can sleep but it should be aware of how that sleep might
+ *   affect others.
+ * - a workitem runs inside a kernel thread so there's no user space to access.
+ * - do not use a workitem if the scheduling latency can't be tolerated.
+ *
+ * When wi_action returns non-zero, it means the workitem has either been
+ * freed or reused and workitem scheduler won't touch it any more.
+ */
+
+#ifndef __LIBCFS_WORKITEM_H__
+#define __LIBCFS_WORKITEM_H__
+
+struct cfs_wi_sched;
+
+void cfs_wi_sched_destroy(struct cfs_wi_sched *);
+int cfs_wi_sched_create(char *name, struct cfs_cpt_table *cptab, int cpt,
+                       int nthrs, struct cfs_wi_sched **);
+
+struct cfs_workitem;
+
+typedef int (*cfs_wi_action_t) (struct cfs_workitem *);
+typedef struct cfs_workitem {
+       /** chain on runq or rerunq */
+       struct list_head       wi_list;
+       /** working function */
+       cfs_wi_action_t  wi_action;
+       /** arg for working function */
+       void        *wi_data;
+       /** in running */
+       unsigned short   wi_running:1;
+       /** scheduled */
+       unsigned short   wi_scheduled:1;
+} cfs_workitem_t;
+
+static inline void
+cfs_wi_init(cfs_workitem_t *wi, void *data, cfs_wi_action_t action)
+{
+       INIT_LIST_HEAD(&wi->wi_list);
+
+       wi->wi_running   = 0;
+       wi->wi_scheduled = 0;
+       wi->wi_data      = data;
+       wi->wi_action    = action;
+}
+
+void cfs_wi_schedule(struct cfs_wi_sched *sched, cfs_workitem_t *wi);
+int  cfs_wi_deschedule(struct cfs_wi_sched *sched, cfs_workitem_t *wi);
+void cfs_wi_exit(struct cfs_wi_sched *sched, cfs_workitem_t *wi);
+
+int  cfs_wi_startup(void);
+void cfs_wi_shutdown(void);
+
+/** # workitem scheduler loops before reschedule */
+#define CFS_WI_RESCHED    128
+
+#endif /* __LIBCFS_WORKITEM_H__ */