src/DiskIO/DiskDaemon/DiskdIOStrategy.h

   1 /*
   2  * Copyright (C) 1996-2020 The Squid Software Foundation and contributors
   3  *
   4  * Squid software is distributed under GPLv2+ license and includes
   5  * contributions from numerous individuals and organizations.
   6  * Please see the COPYING and CONTRIBUTORS files for details.
   7  */
   8
   9 /* DEBUG: section 79    Squid-side DISKD I/O functions. */
  10
  11 #ifndef __STORE_DISKDIOSTRATEGY_H__
  12 #define __STORE_DISKDIOSTRATEGY_H__
  13
  14 struct diomsg;
  15
  16 /// \ingroup diskd
  17 class SharedMemory
  18 {
  19
  20 public:
  21     void put(ssize_t);
  22     void *get(ssize_t *);
  23     void init(int ikey, int magic2);
  24     SharedMemory() : nbufs(0), buf(nullptr), inuse_map(nullptr), id(0) {}
  25
  26     int nbufs;
  27     char *buf;
  28     char *inuse_map;
  29     int id;
  30 };
  31
  32 #include "DiskIO/DiskIOStrategy.h"
  33 #include "StoreIOState.h"
  34
  35 class DiskFile;
  36
  37 class DiskdFile;
  38 class Lock;
  39 class ReadRequest;
  40
  41 /// \ingroup diskd
  42 class DiskdIOStrategy : public DiskIOStrategy
  43 {
  44
  45 public:
  46     DiskdIOStrategy();
  47     virtual bool shedLoad();
  48     virtual int load();
  49     virtual RefCount<DiskFile> newFile(char const *path);
  50     virtual bool unlinkdUseful() const;
  51     virtual void unlinkFile (char const *);
  52     virtual ConfigOption *getOptionTree() const;
  53     virtual void init();
  54     virtual void sync();
  55     virtual int callback();
  56     virtual void statfs(StoreEntry & sentry) const;
  57     int send(int mtype, int id, DiskdFile *theFile, size_t size, off_t offset, ssize_t shm_offset, Lock *requestor);
  58
  59     /** public for accessing return address's */
  60     SharedMemory shm;
  61
  62 private:
  63     static size_t newInstance();
  64     static size_t nextInstanceID;
  65     void openFailed();
  66     bool optionQ1Parse(char const *option, const char *value, int reconfiguring);
  67     void optionQ1Dump(StoreEntry * e) const;
  68     bool optionQ2Parse(char const *option, const char *value, int reconfiguring);
  69     void optionQ2Dump(StoreEntry * e) const;
  70     int send(int mtype, int id, RefCount<StoreIOState> sio, size_t size, off_t offset, ssize_t shm_offset);
  71     int SEND(diomsg * M, int mtype, int id, size_t size, off_t offset, ssize_t shm_offset);
  72     void handle(diomsg * M);
  73     void unlinkDone(diomsg * M);
  74
  75     /**
  76      * magic1 is the number of messages away which we
  77      * stop allowing open/create for.
  78      */
  79     int magic1;
  80
  81     /**
  82      * magic2 is the point at which we start blocking on msgsnd/msgrcv.
  83      * If a queue has magic2 (or more) messages away, then we read the
  84      * queue until the level falls below magic2.  Recommended value
  85      * is 75% of SHMBUFS.
  86      */
  87     int magic2;
  88
  89     int away;
  90     int smsgid;
  91     int rmsgid;
  92     int wfd;
  93     size_t instanceID;
  94 };
  95
  96 /// \ingroup diskd
  97 #define SHMBUF_BLKSZ SM_PAGE_SIZE
  98
  99 /// \ingroup diskd
 100 struct diskd_stats_t {
 101     int open_fail_queue_len;
 102     int block_queue_len;
 103     int max_away;
 104     int max_shmuse;
 105     int shmbuf_count;
 106     int sent_count;
 107     int recv_count;
 108     int sio_id;
 109
 110     struct {
 111         int ops;
 112         int success;
 113         int fail;
 114     }
 115
 116     open, create, close, unlink, read, write;
 117 };
 118
 119 /// \ingroup diskd
 120 extern diskd_stats_t diskd_stats;
 121
 122 #endif
 123