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 #ifdef __cplusplus
  21 extern "C" {
  22 #endif
  23
  24 /*
  25  * These are the value added to the current state depending of the position in
  26  * the thread where is either waiting on a poll() or running in the code.
  27  */
  28 #define HEALTH_POLL_VALUE       (1UL << 0)
  29 #define HEALTH_CODE_VALUE       (1UL << 1)
  30
  31 #define HEALTH_IS_IN_POLL(x)    ((x) & HEALTH_POLL_VALUE)
  32
  33 struct health_app;
  34
  35 enum health_flags {
  36         HEALTH_ERROR                     = (1U << 0),
  37 };
  38
  39 struct health_state {
  40         /*
  41          * last counter and last_time are only read and updated by the health_check
  42          * thread (single updater).
  43          */
  44         unsigned long last;
  45         struct timespec last_time;
  46
  47         /*
  48          * current and flags are updated by multiple threads concurrently.
  49          */
  50         unsigned long current;          /* progress counter, updated atomically */
  51         enum health_flags flags;        /* other flags, updated atomically */
  52         int type;                       /* Indicates the nature of the thread. */
  53         /* Node of the global TLS state list. */
  54         struct cds_list_head node;
  55 };
  56
  57 enum health_cmd {
  58         HEALTH_CMD_CHECK                = 0,
  59 };
  60
  61 struct health_comm_msg {
  62         uint32_t cmd;           /* enum health_cmd */
  63 } LTTNG_PACKED;
  64
  65 struct health_comm_reply {
  66         uint64_t ret_code;      /* bitmask of threads in bad health */
  67 } LTTNG_PACKED;
  68
  69 /* Declare TLS health state. */
  70 extern DECLARE_URCU_TLS(struct health_state, health_state);
  71
  72 /*
  73  * Update current counter by 1 to indicate that the thread entered or left a
  74  * blocking state caused by a poll(). If the counter's value is not an even
  75  * number (meaning a code execution flow), an LTTNG_ASSERT() is raised.
  76  */
  77 static inline void health_poll_entry(void)
  78 {
  79         /* Code MUST be in code execution state which is an even number. */
  80         LTTNG_ASSERT(!(uatomic_read(&URCU_TLS(health_state).current)
  81                                 & HEALTH_POLL_VALUE));
  82
  83         uatomic_add(&URCU_TLS(health_state).current, HEALTH_POLL_VALUE);
  84 }
  85
  86 /*
  87  * Update current counter by 1 indicating the exit of a poll or blocking call.
  88  * If the counter's value is not an odd number (a poll execution), an LTTNG_ASSERT()
  89  * is raised.
  90  */
  91 static inline void health_poll_exit(void)
  92 {
  93         /* Code MUST be in poll execution state which is an odd number. */
  94         LTTNG_ASSERT(uatomic_read(&URCU_TLS(health_state).current)
  95                                 & HEALTH_POLL_VALUE);
  96
  97         uatomic_add(&URCU_TLS(health_state).current, HEALTH_POLL_VALUE);
  98 }
  99
 100 /*
 101  * Update current counter by 2 indicates progress in execution of a
 102  * thread.
 103  */
 104 static inline void health_code_update(void)
 105 {
 106         uatomic_add(&URCU_TLS(health_state).current, HEALTH_CODE_VALUE);
 107 }
 108
 109 /*
 110  * Set health "error" flag.
 111  */
 112 static inline void health_error(void)
 113 {
 114         uatomic_or(&URCU_TLS(health_state).flags, HEALTH_ERROR);
 115 }
 116
 117 struct health_app *health_app_create(int nr_types);
 118 void health_app_destroy(struct health_app *ha);
 119 int health_check_state(struct health_app *ha, int type);
 120 void health_register(struct health_app *ha, int type);
 121 void health_unregister(struct health_app *ha);
 122
 123 #ifdef __cplusplus
 124 }
 125 #endif
 126
 127 #endif /* HEALTH_INTERNAL_H */