lib/workqueue.h

   1 /*
   2  * Quagga Work Queues.
   3  *
   4  * Copyright (C) 2005 Sun Microsystems, Inc.
   5  *
   6  * This file is part of Quagga.
   7  *
   8  * Quagga is free software; you can redistribute it and/or modify it
   9  * under the terms of the GNU General Public License as published by the
  10  * Free Software Foundation; either version 2, or (at your option) any
  11  * later version.
  12  *
  13  * Quagga is distributed in the hope that it will be useful, but
  14  * WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License along
  19  * with this program; see the file COPYING; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  21  */
  22
  23 #ifndef _QUAGGA_WORK_QUEUE_H
  24 #define _QUAGGA_WORK_QUEUE_H
  25
  26 #include "memory.h"
  27 #include "queue.h"
  28 DECLARE_MTYPE(WORK_QUEUE)
  29
  30 /* Hold time for the initial schedule of a queue run, in  millisec */
  31 #define WORK_QUEUE_DEFAULT_HOLD  50
  32
  33 /* action value, for use by item processor and item error handlers */
  34 typedef enum {
  35         WQ_SUCCESS = 0,
  36         WQ_ERROR,        /* Error, run error handler if provided */
  37         WQ_RETRY_NOW,     /* retry immediately */
  38         WQ_RETRY_LATER,   /* retry later, cease processing work queue */
  39         WQ_REQUEUE,       /* requeue item, continue processing work queue */
  40         WQ_QUEUE_BLOCKED, /* Queue cant be processed at this time.
  41                            * Similar to WQ_RETRY_LATER, but doesn't penalise
  42                            * the particular item.. */
  43 } wq_item_status;
  44
  45 /* A single work queue item, unsurprisingly */
  46 struct work_queue_item {
  47         STAILQ_ENTRY(work_queue_item) wq;
  48         void *data;      /* opaque data */
  49         unsigned short ran; /* # of times item has been run */
  50 };
  51
  52 #define WQ_UNPLUGGED    (1 << 0) /* available for draining */
  53
  54 struct work_queue {
  55         /* Everything but the specification struct is private
  56          * the following may be read
  57          */
  58         struct thread_master *master; /* thread master */
  59         struct thread *thread;  /* thread, if one is active */
  60         char *name;                   /* work queue name */
  61
  62         /* Specification for this work queue.
  63          * Public, must be set before use by caller. May be modified at will.
  64          */
  65         struct {
  66                 /* optional opaque user data, global to the queue. */
  67                 void *data;
  68
  69                 /* work function to process items with:
  70                  * First argument is the workqueue queue.
  71                  * Second argument is the item data
  72                  */
  73                 wq_item_status (*workfunc)(struct work_queue *, void *);
  74
  75                 /* error handling function, optional */
  76                 void (*errorfunc)(struct work_queue *,
  77                                   struct work_queue_item *);
  78
  79                 /* callback to delete user specific item data */
  80                 void (*del_item_data)(struct work_queue *, void *);
  81
  82                 /* completion callback, called when queue is emptied, optional
  83                  */
  84                 void (*completion_func)(struct work_queue *);
  85
  86                 /* max number of retries to make for item that errors */
  87                 unsigned int max_retries;
  88
  89                 unsigned int hold; /* hold time for first run, in ms */
  90
  91                 unsigned long
  92                         yield; /* yield time in us for associated thread */
  93         } spec;
  94
  95         /* remaining fields should be opaque to users */
  96         STAILQ_HEAD(work_queue_items, work_queue_item)
  97         items;                /* queue item list */
  98         int item_count;       /* queued items */
  99         unsigned long runs;   /* runs count */
 100         unsigned long yields; /* yields count */
 101
 102         struct {
 103                 unsigned int best;
 104                 unsigned int granularity;
 105                 unsigned long total;
 106         } cycles; /* cycle counts */
 107
 108         /* private state */
 109         u_int16_t flags; /* user set flag */
 110 };
 111
 112 /* User API */
 113
 114 static inline int work_queue_item_count(struct work_queue *wq)
 115 {
 116         return wq->item_count;
 117 }
 118
 119 static inline bool work_queue_empty(struct work_queue *wq)
 120 {
 121         return (wq->item_count == 0) ? true : false;
 122 }
 123
 124 static inline struct work_queue_item *
 125 work_queue_last_item(struct work_queue *wq)
 126 {
 127         return STAILQ_LAST(&wq->items, work_queue_item, wq);
 128 }
 129
 130 static inline void work_queue_item_enqueue(struct work_queue *wq,
 131                                            struct work_queue_item *item)
 132 {
 133         STAILQ_INSERT_TAIL(&wq->items, item, wq);
 134         wq->item_count++;
 135 }
 136
 137 static inline void work_queue_item_dequeue(struct work_queue *wq,
 138                                            struct work_queue_item *item)
 139 {
 140         assert(wq->item_count > 0);
 141
 142         wq->item_count--;
 143         STAILQ_REMOVE(&wq->items, item, work_queue_item, wq);
 144 }
 145
 146 /* create a new work queue, of given name.
 147  * user must fill in the spec of the returned work queue before adding
 148  * anything to it
 149  */
 150 extern struct work_queue *work_queue_new(struct thread_master *, const char *);
 151 /* destroy work queue */
 152 extern void work_queue_free(struct work_queue *);
 153
 154 /* Add the supplied data as an item onto the workqueue */
 155 extern void work_queue_add(struct work_queue *, void *);
 156
 157 /* plug the queue, ie prevent it from being drained / processed */
 158 extern void work_queue_plug(struct work_queue *wq);
 159 /* unplug the queue, allow it to be drained again */
 160 extern void work_queue_unplug(struct work_queue *wq);
 161
 162 bool work_queue_is_scheduled(struct work_queue *);
 163
 164 /* Helpers, exported for thread.c and command.c */
 165 extern int work_queue_run(struct thread *);
 166
 167 extern void workqueue_cmd_init(void);
 168
 169 #endif /* _QUAGGA_WORK_QUEUE_H */