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 #include <common/macros.h>
  30
  31 /*
  32  * These are the value added to the current state depending of the position in
  33  * the thread where is either waiting on a poll() or running in the code.
  34  */
  35 #define HEALTH_POLL_VALUE       (1UL << 0)
  36 #define HEALTH_CODE_VALUE       (1UL << 1)
  37
  38 #define HEALTH_IS_IN_POLL(x)    ((x) & HEALTH_POLL_VALUE)
  39
  40 struct health_app;
  41
  42 enum health_flags {
  43         HEALTH_ERROR                     = (1U << 0),
  44 };
  45
  46 struct health_state {
  47         /*
  48          * last counter and last_time are only read and updated by the health_check
  49          * thread (single updater).
  50          */
  51         unsigned long last;
  52         struct timespec last_time;
  53
  54         /*
  55          * current and flags are updated by multiple threads concurrently.
  56          */
  57         unsigned long current;          /* progress counter, updated atomically */
  58         enum health_flags flags;        /* other flags, updated atomically */
  59         int type;                       /* Indicates the nature of the thread. */
  60         /* Node of the global TLS state list. */
  61         struct cds_list_head node;
  62 };
  63
  64 enum health_cmd {
  65         HEALTH_CMD_CHECK                = 0,
  66 };
  67
  68 struct health_comm_msg {
  69         uint32_t cmd;           /* enum health_cmd */
  70 } LTTNG_PACKED;
  71
  72 struct health_comm_reply {
  73         uint64_t ret_code;      /* bitmask of threads in bad health */
  74 } LTTNG_PACKED;
  75
  76 /* Declare TLS health state. */
  77 extern DECLARE_URCU_TLS(struct health_state, health_state);
  78
  79 /*
  80  * Update current counter by 1 to indicate that the thread entered or left a
  81  * blocking state caused by a poll(). If the counter's value is not an even
  82  * number (meaning a code execution flow), an assert() is raised.
  83  */
  84 static inline void health_poll_entry(void)
  85 {
  86         /* Code MUST be in code execution state which is an even number. */
  87         assert(!(uatomic_read(&URCU_TLS(health_state).current)
  88                                 & HEALTH_POLL_VALUE));
  89
  90         uatomic_add(&URCU_TLS(health_state).current, HEALTH_POLL_VALUE);
  91 }
  92
  93 /*
  94  * Update current counter by 1 indicating the exit of a poll or blocking call.
  95  * If the counter's value is not an odd number (a poll execution), an assert()
  96  * is raised.
  97  */
  98 static inline void health_poll_exit(void)
  99 {
 100         /* Code MUST be in poll execution state which is an odd number. */
 101         assert(uatomic_read(&URCU_TLS(health_state).current)
 102                                 & HEALTH_POLL_VALUE);
 103
 104         uatomic_add(&URCU_TLS(health_state).current, HEALTH_POLL_VALUE);
 105 }
 106
 107 /*
 108  * Update current counter by 2 indicates progress in execution of a
 109  * thread.
 110  */
 111 static inline void health_code_update(void)
 112 {
 113         uatomic_add(&URCU_TLS(health_state).current, HEALTH_CODE_VALUE);
 114 }
 115
 116 /*
 117  * Set health "error" flag.
 118  */
 119 static inline void health_error(void)
 120 {
 121         uatomic_or(&URCU_TLS(health_state).flags, HEALTH_ERROR);
 122 }
 123
 124 struct health_app *health_app_create(int nr_types);
 125 void health_app_destroy(struct health_app *ha);
 126 int health_check_state(struct health_app *ha, int type);
 127 void health_register(struct health_app *ha, int type);
 128 void health_unregister(struct health_app *ha);
 129
 130 #endif /* HEALTH_INTERNAL_H */