src/bin/lttng-sessiond/health.c

   1 /*
   2  * Copyright (C) 2012 - David Goulet <dgoulet@efficios.com>
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU General Public License, version 2 only, as
   6  * published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  11  * more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along with
  14  * this program; if not, write to the Free Software Foundation, Inc., 51
  15  * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  16  */
  17
  18 #define _GNU_SOURCE
  19 #include <assert.h>
  20 #include <inttypes.h>
  21 #include <stdio.h>
  22 #include <stdlib.h>
  23
  24 #include <common/error.h>
  25
  26 #include "health.h"
  27
  28 /*
  29  * Check health of a specific health state counter.
  30  *
  31  * Return 0 if health is bad or else 1.
  32  */
  33 int health_check_state(struct health_state *state)
  34 {
  35         unsigned long current, last;
  36         int ret = 1;
  37
  38         assert(state);
  39
  40         last = state->last;
  41         current = uatomic_read(&state->current);
  42
  43         /*
  44          * Here are the conditions for a bad health. Either flag HEALTH_ERROR is
  45          * set, or the progress counter is the same as the last one and we are NOT
  46          * waiting for a poll() call.
  47          */
  48         if ((uatomic_read(&state->flags) & HEALTH_ERROR) ||
  49                         (current == last && !HEALTH_IS_IN_POLL(current))) {
  50                 /* error */
  51                 ret = 0;
  52         }
  53
  54         DBG("Health state current %" PRIu64 ", last %" PRIu64 ", ret %d",
  55                         current, last, ret);
  56
  57         /*
  58          * Update last counter. This value is and MUST be access only in this
  59          * function.
  60          */
  61         state->last = current;
  62
  63         return ret;
  64 }