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 DECLARE_MTYPE(WORK_QUEUE)
  28
  29 /* Hold time for the initial schedule of a queue run, in  millisec */
  30 #define WORK_QUEUE_DEFAULT_HOLD  50
  31
  32 /* action value, for use by item processor and item error handlers */
  33 typedef enum
  34 {
  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 {
  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 {
  56   /* Everything but the specification struct is private
  57    * the following may be read
  58    */
  59   struct thread_master *master;       /* thread master */
  60   struct thread *thread;              /* thread, if one is active */
  61   char *name;                         /* work queue name */
  62
  63   /* Specification for this work queue.
  64    * Public, must be set before use by caller. May be modified at will.
  65    */
  66   struct {
  67     /* optional opaque user data, global to the queue. */
  68     void *data;
  69
  70     /* work function to process items with:
  71      * First argument is the workqueue queue.
  72      * Second argument is the item data
  73      */
  74     wq_item_status (*workfunc) (struct work_queue *, void *);
  75
  76     /* error handling function, optional */
  77     void (*errorfunc) (struct work_queue *, 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     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 yield; /* yield time in us for associated thread */
  91   } spec;
  92
  93   /* remaining fields should be opaque to users */
  94   struct list *items;                 /* queue item list */
  95   unsigned long runs;                 /* runs count */
  96   unsigned long yields;               /* yields count */
  97
  98   struct {
  99     unsigned int best;
 100     unsigned int granularity;
 101     unsigned long total;
 102   } cycles;     /* cycle counts */
 103
 104   /* private state */
 105   u_int16_t flags;              /* user set flag */
 106 };
 107
 108 /* User API */
 109
 110 /* create a new work queue, of given name.
 111  * user must fill in the spec of the returned work queue before adding
 112  * anything to it
 113  */
 114 extern struct work_queue *work_queue_new (struct thread_master *,
 115                                           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 */