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 {
  36   WQ_SUCCESS = 0,
  37   WQ_ERROR,             /* Error, run error handler if provided */
  38   WQ_RETRY_NOW,         /* retry immediately */
  39   WQ_RETRY_LATER,       /* retry later, cease processing work queue */
  40   WQ_REQUEUE,           /* requeue item, continue processing work queue */
  41   WQ_QUEUE_BLOCKED,     /* Queue cant be processed at this time.
  42                          * Similar to WQ_RETRY_LATER, but doesn't penalise
  43                          * the particular item.. */
  44 } wq_item_status;
  45
  46 /* A single work queue item, unsurprisingly */
  47 struct work_queue_item
  48 {
  49   void *data;                           /* opaque data */
  50   unsigned short ran;                   /* # of times item has been run */
  51 };
  52
  53 #define WQ_UNPLUGGED    (1 << 0) /* available for draining */
  54
  55 struct work_queue
  56 {
  57   /* Everything but the specification struct is private
  58    * the following may be read
  59    */
  60   struct thread_master *master;       /* thread master */
  61   struct thread *thread;              /* thread, if one is active */
  62   char *name;                         /* work queue name */
  63
  64   /* Specification for this work queue.
  65    * Public, must be set before use by caller. May be modified at will.
  66    */
  67   struct {
  68     /* optional opaque user data, global to the queue. */
  69     void *data;
  70
  71     /* work function to process items with:
  72      * First argument is the workqueue queue.
  73      * Second argument is the item data
  74      */
  75     wq_item_status (*workfunc) (struct work_queue *, void *);
  76
  77     /* error handling function, optional */
  78     void (*errorfunc) (struct work_queue *, struct work_queue_item *);
  79
  80     /* callback to delete user specific item data */
  81     void (*del_item_data) (struct work_queue *, void *);
  82
  83     /* completion callback, called when queue is emptied, optional */
  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 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 *,
 116                                           const char *);
 117 /* destroy work queue */
 118 extern void work_queue_free (struct work_queue *);
 119
 120 /* Add the supplied data as an item onto the workqueue */
 121 extern void work_queue_add (struct work_queue *, void *);
 122
 123 /* plug the queue, ie prevent it from being drained / processed */
 124 extern void work_queue_plug (struct work_queue *wq);
 125 /* unplug the queue, allow it to be drained again */
 126 extern void work_queue_unplug (struct work_queue *wq);
 127
 128 bool work_queue_is_scheduled (struct work_queue *);
 129
 130 /* Helpers, exported for thread.c and command.c */
 131 extern int work_queue_run (struct thread *);
 132
 133 extern void workqueue_cmd_init (void);
 134
 135 #endif /* _QUAGGA_WORK_QUEUE_H */