src/helper/ChildConfig.h

   1 /*
   2  * Copyright (C) 1996-2014 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 #ifndef _SQUID_SRC_HELPER_CHILDCONFIG_H
  10 #define _SQUID_SRC_HELPER_CHILDCONFIG_H
  11
  12 namespace Helper
  13 {
  14
  15 /**
  16  * Contains statistics of a particular type of child helper.
  17  *
  18  * Some derived from a helper children configuration option,
  19  * some from runtime stats on the currently active children.
  20  */
  21 class ChildConfig
  22 {
  23 public:
  24     explicit ChildConfig(const unsigned int m = 0);
  25
  26     /**
  27      * When new helpers are needed call this to find out how many more
  28      * we are allowed to start.
  29      * \retval 0       No more helpers may be started right now.
  30      * \retval N < 0   Error. No more helpers may be started.
  31      * \retval N       N more helpers may be started immediately.
  32      */
  33     int needNew() const;
  34     void parseConfig();
  35
  36     /**
  37      * Update an existing set of details with new start/max/idle/concurrent limits.
  38      * This is for parsing new child settings into an object incrementally then updating
  39      * the running set without loosing any of the active state or causing races.
  40      */
  41     ChildConfig &updateLimits(const ChildConfig &rhs);
  42
  43     /* values from squid.conf */
  44 public:
  45
  46     /** maximum child process limits. How many of this helper the system can cope with */
  47     unsigned int n_max;
  48
  49     /**
  50      * Number of children to kick off at startup.
  51      * set via the startup=N option.
  52      *
  53      * By default if undefined 1 will be started immediately for use.
  54      * The minimum/idle amount will be scheduled for starting as soon as possible after startup is completed.
  55      */
  56     unsigned int n_startup;
  57
  58     /**
  59      * Number of helper children to keep available as a buffer against sudden bursts of requests.
  60      * set via the idle=N option. May be zero.
  61      *
  62      * The default value for backward compatibility the default for this is the same as maximum children.
  63      * For now the actual number of idle children is only reduced by a reconfigure operation. This may change.
  64      */
  65     unsigned int n_idle;
  66
  67     /**
  68      * How many concurrent requests each child helper may be capable of handling.
  69      * Default: 0  - no concurrency possible.
  70      */
  71     unsigned int concurrency;
  72
  73     /* derived from active operations */
  74
  75     /**
  76      * Total helper children objects currently existing.
  77      * Produced as a side effect of starting children or their stopping.
  78      */
  79     unsigned int n_running;
  80
  81     /**
  82      * Count of helper children active (not shutting down).
  83      * This includes both idle and in-use children.
  84      */
  85     unsigned int n_active;
  86 };
  87
  88 } // namespace Helper
  89
  90 /* Legacy parser interface */
  91 #define parse_HelperChildConfig(c)     (c)->parseConfig()
  92 #define dump_HelperChildConfig(e,n,c)  storeAppendPrintf((e), "\n%s %d startup=%d idle=%d concurrency=%d\n", (n), (c).n_max, (c).n_startup, (c).n_idle, (c).concurrency)
  93 #define free_HelperChildConfig(dummy)  // NO.
  94
  95 #endif /* _SQUID_SRC_HELPER_CHILDCONFIG_H */