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  * This program is free software; you can redistribute it and/or modify it
   9  * under the terms of the GNU General Public License, version 2 only, as
  10  * published by the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope that it will be useful, but WITHOUT
  13  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  15  * more details.
  16  *
  17  * You should have received a copy of the GNU General Public License along with
  18  * this program; if not, write to the Free Software Foundation, Inc., 51
  19  * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  20  */
  21
  22 #include <assert.h>
  23 #include <time.h>
  24 #include <pthread.h>
  25 #include <urcu/tls-compat.h>
  26 #include <urcu/uatomic.h>
  27 #include <urcu/list.h>
  28 #include <lttng/health.h>
  29
  30 /*
  31  * These are the value added to the current state depending of the position in
  32  * the thread where is either waiting on a poll() or running in the code.
  33  */
  34 #define HEALTH_POLL_VALUE       (1UL << 0)
  35 #define HEALTH_CODE_VALUE       (1UL << 1)
  36
  37 #define HEALTH_IS_IN_POLL(x)    ((x) & HEALTH_POLL_VALUE)
  38
  39 struct health_app;
  40
  41 enum health_flags {
  42         HEALTH_ERROR                     = (1U << 0),
  43 };
  44
  45 struct health_state {
  46         /*
  47          * last counter and last_time are only read and updated by the health_check
  48          * thread (single updater).
  49          */
  50         unsigned long last;
  51         struct timespec last_time;
  52
  53         /*
  54          * current and flags are updated by multiple threads concurrently.
  55          */
  56         unsigned long current;          /* progress counter, updated atomically */
  57         enum health_flags flags;        /* other flags, updated atomically */
  58         int type;                       /* Indicates the nature of the thread. */
  59         /* Node of the global TLS state list. */
  60         struct cds_list_head node;
  61 };
  62
  63 enum health_cmd {
  64         HEALTH_CMD_CHECK                = 0,
  65 };
  66
  67 struct health_comm_msg {
  68         uint32_t component;
  69         uint32_t cmd;           /* enum health_cmd */
  70 } LTTNG_PACKED;
  71
  72 struct health_comm_reply {
  73         uint32_t ret_code;
  74 } LTTNG_PACKED;
  75
  76 /*
  77  * Status returned to lttng clients.
  78  */
  79 struct lttng_health_status {
  80         uint64_t error_threads_bitmask;
  81 };
  82
  83 /* Declare TLS health state. */
  84 extern DECLARE_URCU_TLS(struct health_state, health_state);
  85
  86 /*
  87  * Update current counter by 1 to indicate that the thread entered or left a
  88  * blocking state caused by a poll(). If the counter's value is not an even
  89  * number (meaning a code execution flow), an assert() is raised.
  90  */
  91 static inline void health_poll_entry(void)
  92 {
  93         /* Code MUST be in code execution state which is an even number. */
  94         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 1 indicating the exit of a poll or blocking call.
 102  * If the counter's value is not an odd number (a poll execution), an assert()
 103  * is raised.
 104  */
 105 static inline void health_poll_exit(void)
 106 {
 107         /* Code MUST be in poll execution state which is an odd number. */
 108         assert(uatomic_read(&URCU_TLS(health_state).current)
 109                                 & HEALTH_POLL_VALUE);
 110
 111         uatomic_add(&URCU_TLS(health_state).current, HEALTH_POLL_VALUE);
 112 }
 113
 114 /*
 115  * Update current counter by 2 indicates progress in execution of a
 116  * thread.
 117  */
 118 static inline void health_code_update(void)
 119 {
 120         uatomic_add(&URCU_TLS(health_state).current, HEALTH_CODE_VALUE);
 121 }
 122
 123 /*
 124  * Set health "error" flag.
 125  */
 126 static inline void health_error(void)
 127 {
 128         uatomic_or(&URCU_TLS(health_state).flags, HEALTH_ERROR);
 129 }
 130
 131 struct health_app *health_app_create(int nr_types);
 132 void health_app_destroy(struct health_app *ha);
 133 int health_check_state(struct health_app *ha, int type);
 134 void health_register(struct health_app *ha, int type);
 135 void health_unregister(struct health_app *ha);
 136
 137 #endif /* HEALTH_INTERNAL_H */