include/lttng/health-internal.hpp

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