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