/*

 * Copyright (C) 2014 OpenSIPS Solutions

 *

 * This file is part of opensips, a free SIP server.

 *

 * opensips is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * opensips is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.

 *

 *

 * history:

 * ---------

 *  2014-08-23  created (bogdan)

 */

#include <sys/time.h>

#include <sys/resource.h>

#include "io_wait.h"

#include "globals.h"

/* one reactor per process variable */

io_wait_h _worker_io;

/* max number of fds per reactor */

unsigned int reactor_size = 0;

#define FD_MEM_PERCENT  10

int init_reactor_size(void)

{

  struct rlimit lim;

  int n, pc;

  char *mem_type;

  unsigned long mem_size;

#if defined(PKG_MALLOC)

  mem_type = "pkg";

  mem_size = pkg_mem_size;

#else

  mem_type = "system";

  mem_size = 2*1024*1024*1024UL;  // assume 2Gb per process to avoid reaching limits below

#endif

  n = sizeof(struct fd_map) + sizeof(struct pollfd);

  if (open_files_limit > 0) {

    /* the fd limit was explicitly set, so just follow but only warn

     * if too much memory is to consumed by reactor */

    pc = 100 * n * open_files_limit / mem_size;

    if (pc >= 80) {

      LM_ERR("required memory for a %d files reactor is over 80%% of "

           "the configured %s mem (%luMb)\n",

           open_files_limit, mem_type, mem_size/1024/1024);

      LM_ERR("Please consider increasing the %s memory or reduce the "

           "limit of open files...Exiting\n", mem_type);

      return -1;

    } else if (pc >= 50) {

      LM_WARN("required memory for a %d files reactor is over 50%% of "

          "the configured %s mem (%luMb)\n",

          open_files_limit, mem_type, mem_size/1024/1024);

      LM_WARN("%s memory may not be enough at runtime (consider "

          "increasing it), still continuing\n", mem_type);

    }

    /* seems to have enough mem -> size the reactor based on open files */

    reactor_size = open_files_limit;

  } else {

    /* auto detect the limit of open files */

    if (getrlimit(RLIMIT_NOFILE, &lim)<0){

      LM_ERR("cannot get the maximum number of file descriptors: %s\n",

           strerror(errno));

      return -1;

    }

    /* calculate the size to fit into 10% of mem */

    reactor_size = mem_size / n * FD_MEM_PERCENT / 100;

    if (reactor_size < lim.rlim_cur) {

      LM_WARN("shrinking reactor size from %lu (autodetected via rlimit) "

          "to %d (limited by memory of %d%% from %luMb)\n",

          (unsigned long)lim.rlim_cur, reactor_size, FD_MEM_PERCENT, mem_size/1024/1024);

      LM_WARN("use 'open_files_limit' to enforce other limit or "

          "increase %s memory\n", mem_type);

    } else {

      /* enouhg memory, use as limit the fd limit */

      reactor_size = lim.rlim_cur;

    }

  }

  LM_INFO("reactor size %d (using up to %.2fMb of memory per process)\n",

      reactor_size, 1.0 * n * reactor_size / 1024 / 1024);

  return 0;

}