src/common/defaults.c

   1 /*
   2  * Copyright (C) 2012 - Simon Marchi <simon.marchi@polymtl.ca>
   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 _LGPL_SOURCE
  19 #include <stddef.h>
  20 #include <unistd.h>
  21 #include <stdbool.h>
  22 #include <sys/resource.h>
  23 #include <pthread.h>
  24
  25 #include "defaults.h"
  26 #include "macros.h"
  27 #include "align.h"
  28 #include "error.h"
  29
  30 static bool pthread_attr_init_done;
  31 static pthread_attr_t tattr;
  32 static pthread_mutex_t tattr_lock = PTHREAD_MUTEX_INITIALIZER;
  33
  34 LTTNG_HIDDEN
  35 size_t default_get_channel_subbuf_size(void)
  36 {
  37         return max(_DEFAULT_CHANNEL_SUBBUF_SIZE, PAGE_SIZE);
  38 }
  39
  40 LTTNG_HIDDEN
  41 size_t default_get_metadata_subbuf_size(void)
  42 {
  43         return max(DEFAULT_METADATA_SUBBUF_SIZE, PAGE_SIZE);
  44 }
  45
  46 LTTNG_HIDDEN
  47 size_t default_get_kernel_channel_subbuf_size(void)
  48 {
  49         return max(DEFAULT_KERNEL_CHANNEL_SUBBUF_SIZE, PAGE_SIZE);
  50 }
  51
  52 LTTNG_HIDDEN
  53 size_t default_get_ust_pid_channel_subbuf_size(void)
  54 {
  55         return max(DEFAULT_UST_PID_CHANNEL_SUBBUF_SIZE, PAGE_SIZE);
  56 }
  57
  58 LTTNG_HIDDEN
  59 size_t default_get_ust_uid_channel_subbuf_size(void)
  60 {
  61         return max(DEFAULT_UST_UID_CHANNEL_SUBBUF_SIZE, PAGE_SIZE);
  62 }
  63
  64 LTTNG_HIDDEN
  65 pthread_attr_t *default_pthread_attr(void)
  66 {
  67         int ret = 0;
  68         size_t ptstacksize;
  69         struct rlimit rlim;
  70
  71         pthread_mutex_lock(&tattr_lock);
  72
  73         /* Return cached value. */
  74         if (pthread_attr_init_done) {
  75                 goto end;
  76         }
  77
  78         /* Get system stack size limits. */
  79         ret = getrlimit(RLIMIT_STACK, &rlim);
  80         if (ret < 0) {
  81                 PERROR("getrlimit");
  82                 goto error;
  83         }
  84         DBG("Stack size limits: soft %lld, hard %lld bytes",
  85                         (long long) rlim.rlim_cur,
  86                         (long long) rlim.rlim_max);
  87
  88         /* Get pthread default thread stack size. */
  89         ret = pthread_attr_getstacksize(&tattr, &ptstacksize);
  90         if (ret < 0) {
  91                 PERROR("pthread_attr_getstacksize");
  92                 goto error;
  93         }
  94         DBG("Default pthread stack size is %zu bytes", ptstacksize);
  95
  96         /* Check if the default pthread stack size honors ulimits. */
  97         if (ptstacksize < rlim.rlim_cur) {
  98                 DBG("Your libc doesn't honor stack size limits, setting thread stack size to soft limit (%lld bytes)",
  99                                 (long long) rlim.rlim_cur);
 100
 101                 /* Create pthread_attr_t struct with ulimit stack size. */
 102                 ret = pthread_attr_setstacksize(&tattr, rlim.rlim_cur);
 103                 if (ret < 0) {
 104                         PERROR("pthread_attr_setstacksize");
 105                         goto error;
 106                 }
 107         }
 108
 109         /* Enable cached value. */
 110         pthread_attr_init_done = true;
 111 end:
 112         pthread_mutex_unlock(&tattr_lock);
 113         return &tattr;
 114 error:
 115         pthread_mutex_unlock(&tattr_lock);
 116         WARN("Failed to initialize pthread attributes, using libc defaults.");
 117         return NULL;
 118 }