include/lttng/health-internal.h

   1 #ifndef HEALTH_INTERNAL_H
   2 #define HEALTH_INTERNAL_H
   3
   4 /*
   5  * Copyright (C) 2012 David Goulet <dgoulet@efficios.com>
   6  * Copyright (C) 2013 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   7  *
   8  * SPDX-License-Identifier: GPL-2.0-only
   9  *
  10  */
  11
  12 #include <assert.h>
  13 #include <common/compat/time.h>
  14 #include <pthread.h>
  15 #include <urcu/tls-compat.h>
  16 #include <urcu/uatomic.h>
  17 #include <urcu/list.h>
  18 #include <lttng/health.h>
  19 #include <common/macros.h>
  20
  21 /*
  22  * These are the value added to the current state depending of the position in
  23  * the thread where is either waiting on a poll() or running in the code.
  24  */
  25 #define HEALTH_POLL_VALUE       (1UL << 0)
  26 #define HEALTH_CODE_VALUE       (1UL << 1)
  27
  28 #define HEALTH_IS_IN_POLL(x)    ((x) & HEALTH_POLL_VALUE)
  29
  30 struct health_app;
  31
  32 enum health_flags {
  33         HEALTH_ERROR                     = (1U << 0),
  34 };
  35
  36 struct health_state {
  37         /*
  38          * last counter and last_time are only read and updated by the health_check
  39          * thread (single updater).
  40          */
  41         unsigned long last;
  42         struct timespec last_time;
  43
  44         /*
  45          * current and flags are updated by multiple threads concurrently.
  46          */
  47         unsigned long current;          /* progress counter, updated atomically */
  48         enum health_flags flags;        /* other flags, updated atomically */
  49         int type;                       /* Indicates the nature of the thread. */
  50         /* Node of the global TLS state list. */
  51         struct cds_list_head node;
  52 };
  53
  54 enum health_cmd {
  55         HEALTH_CMD_CHECK                = 0,
  56 };
  57
  58 struct health_comm_msg {
  59         uint32_t cmd;           /* enum health_cmd */
  60 } LTTNG_PACKED;
  61
  62 struct health_comm_reply {
  63         uint64_t ret_code;      /* bitmask of threads in bad health */
  64 } LTTNG_PACKED;
  65
  66 /* Declare TLS health state. */
  67 extern DECLARE_URCU_TLS(struct health_state, health_state);
  68
  69 /*
  70  * Update current counter by 1 to indicate that the thread entered or left a
  71  * blocking state caused by a poll(). If the counter's value is not an even
  72  * number (meaning a code execution flow), an assert() is raised.
  73  */
  74 static inline void health_poll_entry(void)
  75 {
  76         /* Code MUST be in code execution state which is an even number. */
  77         assert(!(uatomic_read(&URCU_TLS(health_state).current)
  78                                 & HEALTH_POLL_VALUE));
  79
  80         uatomic_add(&URCU_TLS(health_state).current, HEALTH_POLL_VALUE);
  81 }
  82
  83 /*
  84  * Update current counter by 1 indicating the exit of a poll or blocking call.
  85  * If the counter's value is not an odd number (a poll execution), an assert()
  86  * is raised.
  87  */
  88 static inline void health_poll_exit(void)
  89 {
  90         /* Code MUST be in poll execution state which is an odd number. */
  91         assert(uatomic_read(&URCU_TLS(health_state).current)
  92                                 & HEALTH_POLL_VALUE);
  93
  94         uatomic_add(&URCU_TLS(health_state).current, HEALTH_POLL_VALUE);
  95 }
  96
  97 /*
  98  * Update current counter by 2 indicates progress in execution of a
  99  * thread.
 100  */
 101 static inline void health_code_update(void)
 102 {
 103         uatomic_add(&URCU_TLS(health_state).current, HEALTH_CODE_VALUE);
 104 }
 105
 106 /*
 107  * Set health "error" flag.
 108  */
 109 static inline void health_error(void)
 110 {
 111         uatomic_or(&URCU_TLS(health_state).flags, HEALTH_ERROR);
 112 }
 113
 114 struct health_app *health_app_create(int nr_types);
 115 void health_app_destroy(struct health_app *ha);
 116 int health_check_state(struct health_app *ha, int type);
 117 void health_register(struct health_app *ha, int type);
 118 void health_unregister(struct health_app *ha);
 119
 120 #endif /* HEALTH_INTERNAL_H */