src/DiskIO/DiskDaemon/DiskdIOStrategy.h

   1 /*
   2  * DEBUG: section 79    Squid-side DISKD I/O functions.
   3  * AUTHOR: Duane Wessels
   4  *
   5  * SQUID Web Proxy Cache          http://www.squid-cache.org/
   6  * ----------------------------------------------------------
   7  *
   8  *  Squid is the result of efforts by numerous individuals from
   9  *  the Internet community; see the CONTRIBUTORS file for full
  10  *  details.   Many organizations have provided support for Squid's
  11  *  development; see the SPONSORS file for full details.  Squid is
  12  *  Copyrighted (C) 2001 by the Regents of the University of
  13  *  California; see the COPYRIGHT file for full details.  Squid
  14  *  incorporates software developed and/or copyrighted by other
  15  *  sources; see the CREDITS file for full details.
  16  *
  17  *  This program is free software; you can redistribute it and/or modify
  18  *  it under the terms of the GNU General Public License as published by
  19  *  the Free Software Foundation; either version 2 of the License, or
  20  *  (at your option) any later version.
  21  *
  22  *  This program is distributed in the hope that it will be useful,
  23  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  24  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  25  *  GNU General Public License for more details.
  26  *
  27  *  You should have received a copy of the GNU General Public License
  28  *  along with this program; if not, write to the Free Software
  29  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
  30  *
  31  * Copyright (c) 2003, Robert Collins <robertc@squid-cache.org>
  32  */
  33
  34 #ifndef __STORE_DISKDIOSTRATEGY_H__
  35 #define __STORE_DISKDIOSTRATEGY_H__
  36
  37 struct diomsg;
  38
  39 /// \ingroup diskd
  40 class SharedMemory
  41 {
  42
  43 public:
  44     void put(ssize_t);
  45
  46     void *get(ssize_t *);
  47
  48     void init(int ikey, int magic2);
  49
  50     int nbufs;
  51
  52     char *buf;
  53
  54     char *inuse_map;
  55
  56     int id;
  57 };
  58
  59 #include "DiskIO/DiskIOStrategy.h"
  60 #include "StoreIOState.h"
  61
  62 class DiskFile;
  63
  64 class DiskdFile;
  65 class Lock;
  66 class ReadRequest;
  67
  68 /// \ingroup diskd
  69 class DiskdIOStrategy : public DiskIOStrategy
  70 {
  71
  72 public:
  73     DiskdIOStrategy();
  74     virtual bool shedLoad();
  75     virtual int load();
  76     virtual RefCount<DiskFile> newFile(char const *path);
  77     virtual bool unlinkdUseful() const;
  78     virtual void unlinkFile (char const *);
  79     virtual ConfigOption *getOptionTree() const;
  80     virtual void init();
  81     virtual void sync();
  82     virtual int callback();
  83     virtual void statfs(StoreEntry & sentry) const;
  84     int send(int mtype, int id, DiskdFile *theFile, size_t size, off_t offset, ssize_t shm_offset, Lock *requestor);
  85
  86     /** public for accessing return address's */
  87     SharedMemory shm;
  88
  89 private:
  90     static size_t newInstance();
  91     static size_t nextInstanceID;
  92     void openFailed();
  93     bool optionQ1Parse(char const *option, const char *value, int reconfiguring);
  94     void optionQ1Dump(StoreEntry * e) const;
  95     bool optionQ2Parse(char const *option, const char *value, int reconfiguring);
  96     void optionQ2Dump(StoreEntry * e) const;
  97     int send(int mtype, int id, RefCount<StoreIOState> sio, size_t size, off_t offset, ssize_t shm_offset);
  98     int SEND(diomsg * M, int mtype, int id, size_t size, off_t offset, ssize_t shm_offset);
  99     void handle(diomsg * M);
 100     void unlinkDone(diomsg * M);
 101
 102     /**
 103      * magic1 is the number of messages away which we
 104      * stop allowing open/create for.
 105      */
 106     int magic1;
 107
 108     /**
 109      * magic2 is the point at which we start blocking on msgsnd/msgrcv.
 110      * If a queue has magic2 (or more) messages away, then we read the
 111      * queue until the level falls below magic2.  Recommended value
 112      * is 75% of SHMBUFS.
 113      */
 114     int magic2;
 115
 116     int away;
 117     int smsgid;
 118     int rmsgid;
 119     int wfd;
 120     size_t instanceID;
 121 };
 122
 123 /// \ingroup diskd
 124 #define SHMBUF_BLKSZ SM_PAGE_SIZE
 125
 126 /// \ingroup diskd
 127 struct diskd_stats_t {
 128     int open_fail_queue_len;
 129     int block_queue_len;
 130     int max_away;
 131     int max_shmuse;
 132     int shmbuf_count;
 133     int sent_count;
 134     int recv_count;
 135     int sio_id;
 136
 137     struct {
 138         int ops;
 139         int success;
 140         int fail;
 141     }
 142
 143     open, create, close, unlink, read, write;
 144 };
 145
 146 /// \ingroup diskd
 147 extern diskd_stats_t diskd_stats;
 148
 149 #endif