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
  29 #ifdef __cplusplus
  30 extern "C" {
  31 #endif
  32
  33 DECLARE_MTYPE(WORK_QUEUE)
  34
  35 /* Hold time for the initial schedule of a queue run, in  millisec */
  36 #define WORK_QUEUE_DEFAULT_HOLD 50
  37
  38 /* Retry for queue that is 'blocked' or 'retry later' */
  39 #define WORK_QUEUE_DEFAULT_RETRY 0
  40
  41 /* action value, for use by item processor and item error handlers */
  42 typedef enum {
  43         WQ_SUCCESS = 0,
  44         WQ_ERROR,        /* Error, run error handler if provided */
  45         WQ_RETRY_NOW,     /* retry immediately */
  46         WQ_RETRY_LATER,   /* retry later, cease processing work queue */
  47         WQ_REQUEUE,       /* requeue item, continue processing work queue */
  48         WQ_QUEUE_BLOCKED, /* Queue cant be processed at this time.
  49                            * Similar to WQ_RETRY_LATER, but doesn't penalise
  50                            * the particular item.. */
  51 } wq_item_status;
  52
  53 /* A single work queue item, unsurprisingly */
  54 struct work_queue_item {
  55         STAILQ_ENTRY(work_queue_item) wq;
  56         void *data;      /* opaque data */
  57         unsigned short ran; /* # of times item has been run */
  58 };
  59
  60 #define WQ_UNPLUGGED    (1 << 0) /* available for draining */
  61
  62 struct work_queue {
  63         /* Everything but the specification struct is private
  64          * the following may be read
  65          */
  66         struct thread_master *master; /* thread master */
  67         struct thread *thread;  /* thread, if one is active */
  68         char *name;                   /* work queue name */
  69
  70         /* Specification for this work queue.
  71          * Public, must be set before use by caller. May be modified at will.
  72          */
  73         struct {
  74                 /* optional opaque user data, global to the queue. */
  75                 void *data;
  76
  77                 /* work function to process items with:
  78                  * First argument is the workqueue queue.
  79                  * Second argument is the item data
  80                  */
  81                 wq_item_status (*workfunc)(struct work_queue *, void *);
  82
  83                 /* error handling function, optional */
  84                 void (*errorfunc)(struct work_queue *,
  85                                   struct work_queue_item *);
  86
  87                 /* callback to delete user specific item data */
  88                 void (*del_item_data)(struct work_queue *, void *);
  89
  90                 /* completion callback, called when queue is emptied, optional
  91                  */
  92                 void (*completion_func)(struct work_queue *);
  93
  94                 /* max number of retries to make for item that errors */
  95                 unsigned int max_retries;
  96
  97                 unsigned int hold; /* hold time for first run, in ms */
  98
  99                 unsigned long
 100                         yield; /* yield time in us for associated thread */
 101
 102                 uint32_t retry; /* Optional retry timeout if queue is blocked */
 103         } spec;
 104
 105         /* remaining fields should be opaque to users */
 106         STAILQ_HEAD(work_queue_items, work_queue_item)
 107         items;                /* queue item list */
 108         int item_count;       /* queued items */
 109         unsigned long runs;   /* runs count */
 110         unsigned long yields; /* yields count */
 111
 112         struct {
 113                 unsigned int best;
 114                 unsigned int granularity;
 115                 unsigned long total;
 116         } cycles; /* cycle counts */
 117
 118         /* private state */
 119         uint16_t flags; /* user set flag */
 120 };
 121
 122 /* User API */
 123
 124 static inline int work_queue_item_count(struct work_queue *wq)
 125 {
 126         return wq->item_count;
 127 }
 128
 129 static inline bool work_queue_empty(struct work_queue *wq)
 130 {
 131         return (wq->item_count == 0) ? true : false;
 132 }
 133
 134 static inline struct work_queue_item *
 135 work_queue_last_item(struct work_queue *wq)
 136 {
 137         return STAILQ_LAST(&wq->items, work_queue_item, wq);
 138 }
 139
 140 static inline void work_queue_item_enqueue(struct work_queue *wq,
 141                                            struct work_queue_item *item)
 142 {
 143         STAILQ_INSERT_TAIL(&wq->items, item, wq);
 144         wq->item_count++;
 145 }
 146
 147 static inline void work_queue_item_dequeue(struct work_queue *wq,
 148                                            struct work_queue_item *item)
 149 {
 150         assert(wq->item_count > 0);
 151
 152         wq->item_count--;
 153         STAILQ_REMOVE(&wq->items, item, work_queue_item, wq);
 154 }
 155
 156 /* create a new work queue, of given name.
 157  * user must fill in the spec of the returned work queue before adding
 158  * anything to it
 159  */
 160 extern struct work_queue *work_queue_new(struct thread_master *, const char *);
 161
 162 /* destroy work queue */
 163 /*
 164  * The usage of work_queue_free is being transitioned to pass
 165  * in the double pointer to remove use after free's.
 166  */
 167 extern void work_queue_free_and_null(struct work_queue **wqp);
 168
 169 /* Add the supplied data as an item onto the workqueue */
 170 extern void work_queue_add(struct work_queue *wq, void *item);
 171
 172 /* plug the queue, ie prevent it from being drained / processed */
 173 extern void work_queue_plug(struct work_queue *wq);
 174 /* unplug the queue, allow it to be drained again */
 175 extern void work_queue_unplug(struct work_queue *wq);
 176
 177 bool work_queue_is_scheduled(struct work_queue *);
 178
 179 /* Helpers, exported for thread.c and command.c */
 180 extern int work_queue_run(struct thread *);
 181
 182 extern void workqueue_cmd_init(void);
 183
 184 #ifdef __cplusplus
 185 }
 186 #endif
 187
 188 #endif /* _QUAGGA_WORK_QUEUE_H */