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
  19  * along with Quagga; see the file COPYING.  If not, write to the Free
  20  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  21  * 02111-1307, USA.
  22  */
  23
  24 #ifndef _QUAGGA_WORK_QUEUE_H
  25 #define _QUAGGA_WORK_QUEUE_H
  26
  27 #include "memory.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         void *data;      /* opaque data */
  48         unsigned short ran; /* # of times item has been run */
  49 };
  50
  51 #define WQ_UNPLUGGED    (1 << 0) /* available for draining */
  52
  53 struct work_queue {
  54         /* Everything but the specification struct is private
  55          * the following may be read
  56          */
  57         struct thread_master *master; /* thread master */
  58         struct thread *thread;  /* thread, if one is active */
  59         char *name;                   /* work queue name */
  60
  61         /* Specification for this work queue.
  62          * Public, must be set before use by caller. May be modified at will.
  63          */
  64         struct {
  65                 /* optional opaque user data, global to the queue. */
  66                 void *data;
  67
  68                 /* work function to process items with:
  69                  * First argument is the workqueue queue.
  70                  * Second argument is the item data
  71                  */
  72                 wq_item_status (*workfunc)(struct work_queue *, void *);
  73
  74                 /* error handling function, optional */
  75                 void (*errorfunc)(struct work_queue *,
  76                                   struct work_queue_item *);
  77
  78                 /* callback to delete user specific item data */
  79                 void (*del_item_data)(struct work_queue *, void *);
  80
  81                 /* completion callback, called when queue is emptied, optional
  82                  */
  83                 void (*completion_func)(struct work_queue *);
  84
  85                 /* max number of retries to make for item that errors */
  86                 unsigned int max_retries;
  87
  88                 unsigned int hold; /* hold time for first run, in ms */
  89
  90                 unsigned long
  91                         yield; /* yield time in us for associated thread */
  92         } spec;
  93
  94         /* remaining fields should be opaque to users */
  95         struct list *items;   /* queue item list */
  96         unsigned long runs;   /* runs count */
  97         unsigned long yields; /* yields count */
  98
  99         struct {
 100                 unsigned int best;
 101                 unsigned int granularity;
 102                 unsigned long total;
 103         } cycles; /* cycle counts */
 104
 105         /* private state */
 106         u_int16_t flags; /* user set flag */
 107 };
 108
 109 /* User API */
 110
 111 /* create a new work queue, of given name.
 112  * user must fill in the spec of the returned work queue before adding
 113  * anything to it
 114  */
 115 extern struct work_queue *work_queue_new(struct thread_master *, const char *);
 116 /* destroy work queue */
 117 extern void work_queue_free(struct work_queue *);
 118
 119 /* Add the supplied data as an item onto the workqueue */
 120 extern void work_queue_add(struct work_queue *, void *);
 121
 122 /* plug the queue, ie prevent it from being drained / processed */
 123 extern void work_queue_plug(struct work_queue *wq);
 124 /* unplug the queue, allow it to be drained again */
 125 extern void work_queue_unplug(struct work_queue *wq);
 126
 127 bool work_queue_is_scheduled(struct work_queue *);
 128
 129 /* Helpers, exported for thread.c and command.c */
 130 extern int work_queue_run(struct thread *);
 131
 132 extern void workqueue_cmd_init(void);
 133
 134 #endif /* _QUAGGA_WORK_QUEUE_H */