cpuplugd/mem.c

   1 /*
   2  * Copyright IBM Corp 2007
   3  * Author: Hans-Joachim Picht <hans@linux.vnet.ibm.com>
   4  *
   5  * Linux for System z Hotplug Daemon
   6  *
   7  * This program is free software; you can redistribute it and/or modify it
   8  * under the terms of the GNU General Public License as published by the Free
   9  * Software Foundation; either version 2 of the License, or (at your option)
  10  * any later version.
  11  *
  12  * You should have received a copy of the GNU General Public License
  13  * along with this program; if not, write to the Free Software
  14  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  15  */
  16
  17
  18
  19 #include <ctype.h>
  20 #include <getopt.h>
  21 #include <stdio.h>
  22 #include <stdlib.h>
  23 #include <unistd.h>
  24 #include <errno.h>
  25 #include <string.h>
  26 #include <fcntl.h>
  27 #include <sys/stat.h>
  28 #include <sys/wait.h>
  29 #include <sys/types.h>
  30 #include <signal.h>
  31 #include <syslog.h>
  32 #include <pthread.h>
  33 #include <linux/param.h>
  34 #include <assert.h>
  35 #include <fcntl.h>
  36 #include <limits.h>
  37 #include <termios.h>
  38 #include <sys/types.h>
  39 #include <sys/ioctl.h>
  40 #include <sys/dir.h>
  41 #include <dirent.h>
  42 #include "cpuplugd.h"
  43
  44 /*
  45  * return page in and out as well as the page
  46  * swap in and out rate based on /proc/vmstat
  47  */
  48 int get_vmstats(struct vm_info *v)
  49 {
  50         FILE *filp;
  51         size_t bytes_read;
  52         char buffer[2048];
  53         char *match_pgpgout;
  54         char *match_pswpout;
  55         char *match_pgpgin;
  56         char *match_pswpin;
  57         int pgpgout;            /* page out */
  58         int pswpout;            /* page swap out */
  59         int pswpin;             /* page swap in */
  60         int pgpgin;             /* page in */
  61         int rc;
  62
  63         filp = fopen("/proc/vmstat", "r");
  64         if (!filp) {
  65                 fprintf(stderr, "Can not open /proc/vmstat:");
  66                 fprintf(stderr, "%s\n", strerror(errno));
  67                 if (foreground == 0)
  68                         syslog(LOG_ERR, "Can not open /proc/vmstat"
  69                                ":%s\n", strerror(errno));
  70                 rc = -1;
  71                 goto out;
  72         }
  73         bytes_read = fread(buffer, 1, sizeof(buffer), filp);
  74         /*
  75          * Bail if read failed or the buffer isn't big enough
  76          */
  77         if (bytes_read == 0) {
  78                 fprintf(stderr, "Reading /proc/vmstat failed:");
  79                 fprintf(stderr, "%s\n", strerror(errno));
  80                 if (foreground == 0)
  81                         syslog(LOG_ERR, "Reading /proc/vmstat failed"
  82                         ":%s\n", strerror(errno));
  83                 rc = -1;
  84                 goto outc;
  85         }
  86          /*
  87           * NUL-terminate the text
  88           */
  89         buffer[bytes_read] = '\0';
  90         match_pgpgout = strstr(buffer, "pgpgout");
  91         match_pswpout = strstr(buffer, "pswpout");
  92         match_pgpgin = strstr(buffer, "pgpgin");
  93         match_pswpin = strstr(buffer, "pswpin");
  94         if (match_pgpgout == NULL || match_pswpout == NULL ||
  95                 match_pgpgin == NULL || match_pswpin == NULL) {
  96                 rc = -1;
  97                 goto outc;
  98         }
  99         sscanf(match_pgpgout, "pgpgout %d", &pgpgout);
 100         sscanf(match_pswpout, "pswpout %d", &pswpout);
 101         sscanf(match_pgpgin, "pgpgin %d", &pgpgin);
 102         sscanf(match_pswpin, "pswpin %d", &pswpin);
 103         v->pgpgout = pgpgout;
 104         v->pswpout = pswpout;
 105         v->pgpgin = pgpgin;
 106         v->pswpin = pswpin;
 107         rc = 0;
 108 outc:
 109         fclose(filp);
 110 out:
 111         return rc;
 112 }
 113
 114 /*
 115  * The cmm_pages value defines the size of the balloon of blocked memory.
 116  * Increasing the value is removing memory from Linux, which is an memunplug.
 117  * Decreasing the value is adding memory back to Linux, which is memplug.
 118  */
 119
 120 /*
 121  *  increase number of pages permanently reserved
 122  */
 123 int memunplug(int size)
 124 {
 125         int old_size, new_size;
 126         FILE *filp;
 127
 128         old_size = get_cmmpages_size();
 129         /*
 130          * new value: previous value + size
 131          */
 132         new_size = old_size + size;
 133         filp = fopen("/proc/sys/vm/cmm_pages", "w");
 134         if (!filp) {
 135                 fprintf(stderr, "Can not open /proc/sys/vm/cmm_pages: %s\n",
 136                                 strerror(errno));
 137                 if (foreground == 0)
 138                         syslog(LOG_ERR, "Can not open /proc/sys/vm/cmm_pages"
 139                                ":%s\n", strerror(errno));
 140                 return -1;
 141         }
 142         fprintf(filp, "%d\n", new_size);
 143         if (debug && foreground == 1)
 144                 printf("changed number of pages permanently reserved "
 145                        "to  %d \n", new_size);
 146         if (debug && foreground == 0)
 147                 syslog(LOG_INFO, "changed number of pages permanently"
 148                                " reserved to %d \n", new_size);
 149         fclose(filp);
 150         return 1;
 151 }
 152
 153 /*
 154  *  decrease number of pages permanently reserved
 155  */
 156 int memplug(int size)
 157 {
 158         int old_size, new_size;
 159         FILE *filp;
 160
 161         old_size = get_cmmpages_size();
 162         /*
 163          * new value: previous value - size
 164          */
 165         new_size = old_size - size;
 166         if (new_size <= 0)
 167                 return -1;
 168         filp = fopen("/proc/sys/vm/cmm_pages", "w");
 169         if (!filp) {
 170                 fprintf(stderr, "Can not open /proc/sys/vm/cmmpages: %s\n",
 171                                 strerror(errno));
 172                 if (foreground == 0)
 173                         syslog(LOG_ERR, "Can not open /proc/sys/vm/cmm_pages"
 174                                ":%s\n", strerror(errno));
 175                 return -1;
 176         }
 177         fprintf(filp, "%d\n", new_size);
 178         if (debug && foreground == 1)
 179                 printf("changed number of pages permanently reserved "
 180                        "to  %d \n", new_size);
 181         if (debug && foreground == 0)
 182                 syslog(LOG_INFO, "changed number of pages permanently"
 183                                 "reserved to %d \n", new_size);
 184         fclose(filp);
 185         return 1;
 186 }
 187
 188 /*
 189  *  override the value of cmm_pages
 190  */
 191 int set_cmm_pages(int size)
 192 {
 193         FILE *filp;
 194
 195         filp = fopen("/proc/sys/vm/cmm_pages", "w");
 196         if (!filp) {
 197                 fprintf(stderr, "Can not open /proc/sys/vm/cmmpages: %s\n",
 198                                 strerror(errno));
 199                 if (foreground == 0)
 200                         syslog(LOG_ERR, "Can not open /proc/sys/vm/cmm_pages"
 201                                ":%s\n", strerror(errno));
 202                 return -1;
 203         }
 204         fprintf(filp, "%d\n", size);
 205         if (debug && foreground == 1)
 206                 printf("changed number of pages permanently reserved "
 207                        "to  %d \n", size);
 208         if (debug && foreground == 0)
 209                 syslog(LOG_INFO, "changed number of pages permanently"
 210                                 "reserved to %d \n", size);
 211         fclose(filp);
 212         return 1;
 213 }
 214 /*
 215  *  read number of pages permanently reserved
 216  */
 217 int get_cmmpages_size()
 218 {
 219         FILE *filp;
 220         int size;
 221         int rc;
 222
 223         filp = fopen("/proc/sys/vm/cmm_pages", "r");
 224         if (!filp) {
 225                 fprintf(stderr, "Can not open /proc/sys/vm/cmm_pages: %s\n",
 226                                 strerror(errno));
 227                 if (foreground == 0)
 228                         syslog(LOG_ERR, "Can not open /proc/sys/vm/cmm_pages"
 229                                ":%s\n", strerror(errno));
 230                 return -1;
 231         }
 232         rc = fscanf(filp, "%d", &size);
 233         if (rc != 0) {
 234                 fprintf(stderr, "Can not read /proc/sys/vm/cmm_pages: %s\n",
 235                                 strerror(errno));
 236                 if (foreground == 0)
 237                         syslog(LOG_ERR, "Can not read /proc/sys/vm/cmm_pages"
 238                                ":%s\n", strerror(errno));
 239                 return -1;
 240         }
 241         fclose(filp);
 242         return size;
 243 }
 244
 245
 246
 247 /*
 248  *  reset cmm pagesize to value we found prior to daemon startup
 249  */
 250 int cleanup_cmm()
 251 {
 252         FILE *filp;
 253
 254         filp = fopen("/proc/sys/vm/cmm_pages", "w");
 255         if (!filp) {
 256                 fprintf(stderr, "Can not open /proc/sys/vm/cmm_pages: %s\n",
 257                                 strerror(errno));
 258                 if (foreground == 0)
 259                         syslog(LOG_ERR, "Can not open /proc/sys/vm/cmm_pages"
 260                                ":%s\n", strerror(errno));
 261                 return -1;
 262         }
 263         fprintf(filp, "%d", cmm_pagesize_start);
 264         if (debug && foreground == 1)
 265                 printf("changed number of pages permanently reserved"
 266                        " to  %d \n", cmm_pagesize_start);
 267         if (debug && foreground == 0)
 268                 syslog(LOG_INFO, "changed number of pages permanently "
 269                                  " reserved to %d \n",
 270                                 cmm_pagesize_start);
 271         fclose(filp);
 272         return 1;
 273 }
 274
 275
 276
 277
 278 /*
 279  *  function to check if the cmm kernel module is loaded and the required
 280  *  files below /proc exit
 281  */
 282 int check_cmmfiles(void)
 283 {
 284         FILE *filp;
 285
 286         filp = fopen("/proc/sys/vm/cmm_pages", "r");
 287         if (!filp)
 288                 return -1;
 289         fclose(filp);
 290         return 0;
 291 }
 292
 293
 294 /*
 295  * return amount of *free* memory as reported by
 296  * /proc/meminfo
 297  */
 298 int get_free_memsize()
 299 {
 300         int size;
 301         int rc;
 302         FILE *filp;
 303         size_t bytes_read;
 304         char buffer[2048];
 305         char *match;
 306
 307         size = 1;
 308         rc = 1;
 309         filp = fopen("/proc/meminfo", "r");
 310         if (!filp) {
 311                 fprintf(stderr, "%s\n", strerror(errno));
 312                 if (foreground == 0)
 313                         syslog(LOG_ERR, "Can not open /proc/meminfo"
 314                                ":%s\n", strerror(errno));
 315                 clean_up();
 316         }
 317         bytes_read = fread(buffer, 1, sizeof(buffer), filp);
 318         /*
 319          * Bail if read failed or the buffer isn't big enough
 320          */
 321         if (bytes_read == 0) {
 322                 fprintf(stderr, "Reading /proc/meminfo failed:");
 323                 fprintf(stderr, "%s\n", strerror(errno));
 324                 if (foreground == 0)
 325                         syslog(LOG_ERR, "Reading /proc/meminfo failed"
 326                         ":%s\n", strerror(errno));
 327                 clean_up();
 328         }
 329         buffer[bytes_read] = '\0';
 330         /*
 331          * Locate the line that starts with
 332          * "MemTotal".
 333          */
 334         match = strstr(buffer, "MemFree");
 335         if (match == NULL) {
 336                 fprintf(stderr, "No MemFree entry found in /proc/meminfo\n");
 337                 clean_up();
 338         } else {
 339                 /*
 340                  * Parse the line to extract
 341                  * the amount of memory
 342                  */
 343                 rc = sscanf(match, "MemFree : %d", &size);
 344         }
 345         fclose(filp);
 346         /* KB to MB */
 347         if (rc == 1)
 348                 return size / 1024;
 349         else
 350                 return -1;
 351 }
 352
 353
 354
 355