arch/s390/mm/cmm.c

   1 /*
   2  *  arch/s390/mm/cmm.c
   3  *
   4  *  S390 version
   5  *    Copyright (C) 2003 IBM Deutschland Entwicklung GmbH, IBM Corporation
   6  *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
   7  *
   8  *  Collaborative memory management interface.
   9  */
  10
  11 #include <linux/config.h>
  12 #include <linux/errno.h>
  13 #include <linux/fs.h>
  14 #include <linux/init.h>
  15 #include <linux/module.h>
  16 #include <linux/sched.h>
  17 #include <linux/sysctl.h>
  18 #include <linux/ctype.h>
  19
  20 #include <asm/pgalloc.h>
  21 #include <asm/uaccess.h>
  22
  23 #include "../../../drivers/s390/net/smsgiucv.h"
  24
  25 #define CMM_NR_PAGES ((PAGE_SIZE / sizeof(unsigned long)) - 2)
  26
  27 struct cmm_page_array {
  28         struct cmm_page_array *next;
  29         unsigned long index;
  30         unsigned long pages[CMM_NR_PAGES];
  31 };
  32
  33 static long cmm_pages = 0;
  34 static long cmm_timed_pages = 0;
  35 static volatile long cmm_pages_target = 0;
  36 static volatile long cmm_timed_pages_target = 0;
  37 static long cmm_timeout_pages = 0;
  38 static long cmm_timeout_seconds = 0;
  39
  40 static struct cmm_page_array *cmm_page_list = 0;
  41 static struct cmm_page_array *cmm_timed_page_list = 0;
  42
  43 static unsigned long cmm_thread_active = 0;
  44 static struct work_struct cmm_thread_starter;
  45 static wait_queue_head_t cmm_thread_wait;
  46 static struct timer_list cmm_timer;
  47
  48 static void cmm_timer_fn(unsigned long);
  49 static void cmm_set_timer(void);
  50
  51 static long
  52 cmm_strtoul(const char *cp, char **endp)
  53 {
  54         unsigned int base = 10;
  55
  56         if (*cp == '0') {
  57                 base = 8;
  58                 cp++;
  59                 if ((*cp == 'x' || *cp == 'X') && isxdigit(cp[1])) {
  60                         base = 16;
  61                         cp++;
  62                 }
  63         }
  64         return simple_strtoul(cp, endp, base);
  65 }
  66
  67 static long
  68 cmm_alloc_pages(long pages, long *counter, struct cmm_page_array **list)
  69 {
  70         struct cmm_page_array *pa;
  71         unsigned long page;
  72
  73         pa = *list;
  74         while (pages) {
  75                 page = __get_free_page(GFP_NOIO);
  76                 if (!page)
  77                         break;
  78                 if (!pa || pa->index >= CMM_NR_PAGES) {
  79                         /* Need a new page for the page list. */
  80                         pa = (struct cmm_page_array *)
  81                                 __get_free_page(GFP_NOIO);
  82                         if (!pa) {
  83                                 free_page(page);
  84                                 break;
  85                         }
  86                         pa->next = *list;
  87                         pa->index = 0;
  88                         *list = pa;
  89                 }
  90                 diag10(page);
  91                 pa->pages[pa->index++] = page;
  92                 (*counter)++;
  93                 pages--;
  94         }
  95         return pages;
  96 }
  97
  98 static void
  99 cmm_free_pages(long pages, long *counter, struct cmm_page_array **list)
 100 {
 101         struct cmm_page_array *pa;
 102         unsigned long page;
 103
 104         pa = *list;
 105         while (pages) {
 106                 if (!pa || pa->index <= 0)
 107                         break;
 108                 page = pa->pages[--pa->index];
 109                 if (pa->index == 0) {
 110                         pa = pa->next;
 111                         free_page((unsigned long) *list);
 112                         *list = pa;
 113                 }
 114                 free_page(page);
 115                 (*counter)--;
 116                 pages--;
 117         }
 118 }
 119
 120 static int
 121 cmm_thread(void *dummy)
 122 {
 123         int rc;
 124
 125         daemonize("cmmthread");
 126         while (1) {
 127                 rc = wait_event_interruptible(cmm_thread_wait,
 128                         (cmm_pages != cmm_pages_target ||
 129                          cmm_timed_pages != cmm_timed_pages_target));
 130                 if (rc == -ERESTARTSYS) {
 131                         /* Got kill signal. End thread. */
 132                         clear_bit(0, &cmm_thread_active);
 133                         cmm_pages_target = cmm_pages;
 134                         cmm_timed_pages_target = cmm_timed_pages;
 135                         break;
 136                 }
 137                 if (cmm_pages_target > cmm_pages) {
 138                         if (cmm_alloc_pages(1, &cmm_pages, &cmm_page_list))
 139                                 cmm_pages_target = cmm_pages;
 140                 } else if (cmm_pages_target < cmm_pages) {
 141                         cmm_free_pages(1, &cmm_pages, &cmm_page_list);
 142                 }
 143                 if (cmm_timed_pages_target > cmm_timed_pages) {
 144                         if (cmm_alloc_pages(1, &cmm_timed_pages,
 145                                            &cmm_timed_page_list))
 146                                 cmm_timed_pages_target = cmm_timed_pages;
 147                 } else if (cmm_timed_pages_target < cmm_timed_pages) {
 148                         cmm_free_pages(1, &cmm_timed_pages,
 149                                        &cmm_timed_page_list);
 150                 }
 151                 if (cmm_timed_pages > 0 && !timer_pending(&cmm_timer))
 152                         cmm_set_timer();
 153         }
 154         return 0;
 155 }
 156
 157 static void
 158 cmm_start_thread(void)
 159 {
 160         kernel_thread(cmm_thread, 0, 0);
 161 }
 162
 163 static void
 164 cmm_kick_thread(void)
 165 {
 166         if (!test_and_set_bit(0, &cmm_thread_active))
 167                 schedule_work(&cmm_thread_starter);
 168         wake_up(&cmm_thread_wait);
 169 }
 170
 171 static void
 172 cmm_set_timer(void)
 173 {
 174         if (cmm_timed_pages_target <= 0 || cmm_timeout_seconds <= 0) {
 175                 if (timer_pending(&cmm_timer))
 176                         del_timer(&cmm_timer);
 177                 return;
 178         }
 179         if (timer_pending(&cmm_timer)) {
 180                 if (mod_timer(&cmm_timer, jiffies + cmm_timeout_seconds*HZ))
 181                         return;
 182         }
 183         cmm_timer.function = cmm_timer_fn;
 184         cmm_timer.data = 0;
 185         cmm_timer.expires = jiffies + cmm_timeout_seconds*HZ;
 186         add_timer(&cmm_timer);
 187 }
 188
 189 static void
 190 cmm_timer_fn(unsigned long ignored)
 191 {
 192         long pages;
 193
 194         pages = cmm_timed_pages_target - cmm_timeout_pages;
 195         if (pages < 0)
 196                 cmm_timed_pages_target = 0;
 197         else
 198                 cmm_timed_pages_target = pages;
 199         cmm_kick_thread();
 200         cmm_set_timer();
 201 }
 202
 203 void
 204 cmm_set_pages(long pages)
 205 {
 206         cmm_pages_target = pages;
 207         cmm_kick_thread();
 208 }
 209
 210 long
 211 cmm_get_pages(void)
 212 {
 213         return cmm_pages;
 214 }
 215
 216 void
 217 cmm_add_timed_pages(long pages)
 218 {
 219         cmm_timed_pages_target += pages;
 220         cmm_kick_thread();
 221 }
 222
 223 long
 224 cmm_get_timed_pages(void)
 225 {
 226         return cmm_timed_pages;
 227 }
 228
 229 void
 230 cmm_set_timeout(long pages, long seconds)
 231 {
 232         cmm_timeout_pages = pages;
 233         cmm_timeout_seconds = seconds;
 234         cmm_set_timer();
 235 }
 236
 237 static inline int
 238 cmm_skip_blanks(char *cp, char **endp)
 239 {
 240         char *str;
 241
 242         for (str = cp; *str == ' ' || *str == '\t'; str++);
 243         *endp = str;
 244         return str != cp;
 245 }
 246
 247 #ifdef CONFIG_CMM_PROC
 248 /* These will someday get removed. */
 249 #define VM_CMM_PAGES            1111
 250 #define VM_CMM_TIMED_PAGES      1112
 251 #define VM_CMM_TIMEOUT          1113
 252
 253 static struct ctl_table cmm_table[];
 254
 255 static int
 256 cmm_pages_handler(ctl_table *ctl, int write, struct file *filp,
 257                   void *buffer, size_t *lenp, loff_t *ppos)
 258 {
 259         char buf[16], *p;
 260         long pages;
 261         int len;
 262
 263         if (!*lenp || (*ppos && !write)) {
 264                 *lenp = 0;
 265                 return 0;
 266         }
 267
 268         if (write) {
 269                 len = *lenp;
 270                 if (copy_from_user(buf, buffer,
 271                                    len > sizeof(buf) ? sizeof(buf) : len))
 272                         return -EFAULT;
 273                 buf[sizeof(buf) - 1] = '\0';
 274                 cmm_skip_blanks(buf, &p);
 275                 pages = cmm_strtoul(p, &p);
 276                 if (ctl == &cmm_table[0])
 277                         cmm_set_pages(pages);
 278                 else
 279                         cmm_add_timed_pages(pages);
 280         } else {
 281                 if (ctl == &cmm_table[0])
 282                         pages = cmm_get_pages();
 283                 else
 284                         pages = cmm_get_timed_pages();
 285                 len = sprintf(buf, "%ld\n", pages);
 286                 if (len > *lenp)
 287                         len = *lenp;
 288                 if (copy_to_user(buffer, buf, len))
 289                         return -EFAULT;
 290         }
 291         *lenp = len;
 292         *ppos += len;
 293         return 0;
 294 }
 295
 296 static int
 297 cmm_timeout_handler(ctl_table *ctl, int write, struct file *filp,
 298                     void *buffer, size_t *lenp, loff_t *ppos)
 299 {
 300         char buf[64], *p;
 301         long pages, seconds;
 302         int len;
 303
 304         if (!*lenp || (*ppos && !write)) {
 305                 *lenp = 0;
 306                 return 0;
 307         }
 308
 309         if (write) {
 310                 len = *lenp;
 311                 if (copy_from_user(buf, buffer,
 312                                    len > sizeof(buf) ? sizeof(buf) : len))
 313                         return -EFAULT;
 314                 buf[sizeof(buf) - 1] = '\0';
 315                 cmm_skip_blanks(buf, &p);
 316                 pages = cmm_strtoul(p, &p);
 317                 cmm_skip_blanks(p, &p);
 318                 seconds = cmm_strtoul(p, &p);
 319                 cmm_set_timeout(pages, seconds);
 320         } else {
 321                 len = sprintf(buf, "%ld %ld\n",
 322                               cmm_timeout_pages, cmm_timeout_seconds);
 323                 if (len > *lenp)
 324                         len = *lenp;
 325                 if (copy_to_user(buffer, buf, len))
 326                         return -EFAULT;
 327         }
 328         *lenp = len;
 329         *ppos += len;
 330         return 0;
 331 }
 332
 333 static struct ctl_table cmm_table[] = {
 334         {
 335                 .ctl_name       = VM_CMM_PAGES,
 336                 .procname       = "cmm_pages",
 337                 .mode           = 0600,
 338                 .proc_handler   = &cmm_pages_handler,
 339         },
 340         {
 341                 .ctl_name       = VM_CMM_TIMED_PAGES,
 342                 .procname       = "cmm_timed_pages",
 343                 .mode           = 0600,
 344                 .proc_handler   = &cmm_pages_handler,
 345         },
 346         {
 347                 .ctl_name       = VM_CMM_TIMEOUT,
 348                 .procname       = "cmm_timeout",
 349                 .mode           = 0600,
 350                 .proc_handler   = &cmm_timeout_handler,
 351         },
 352         { .ctl_name = 0 }
 353 };
 354
 355 static struct ctl_table cmm_dir_table[] = {
 356         {
 357                 .ctl_name       = CTL_VM,
 358                 .procname       = "vm",
 359                 .maxlen         = 0,
 360                 .mode           = 0555,
 361                 .child          = cmm_table,
 362         },
 363         { .ctl_name = 0 }
 364 };
 365 #endif
 366
 367 #ifdef CONFIG_CMM_IUCV
 368 #define SMSG_PREFIX "CMM"
 369 static void
 370 cmm_smsg_target(char *msg)
 371 {
 372         long pages, seconds;
 373
 374         if (!cmm_skip_blanks(msg + strlen(SMSG_PREFIX), &msg))
 375                 return;
 376         if (strncmp(msg, "SHRINK", 6) == 0) {
 377                 if (!cmm_skip_blanks(msg + 6, &msg))
 378                         return;
 379                 pages = cmm_strtoul(msg, &msg);
 380                 cmm_skip_blanks(msg, &msg);
 381                 if (*msg == '\0')
 382                         cmm_set_pages(pages);
 383         } else if (strncmp(msg, "RELEASE", 7) == 0) {
 384                 if (!cmm_skip_blanks(msg + 7, &msg))
 385                         return;
 386                 pages = cmm_strtoul(msg, &msg);
 387                 cmm_skip_blanks(msg, &msg);
 388                 if (*msg == '\0')
 389                         cmm_add_timed_pages(pages);
 390         } else if (strncmp(msg, "REUSE", 5) == 0) {
 391                 if (!cmm_skip_blanks(msg + 5, &msg))
 392                         return;
 393                 pages = cmm_strtoul(msg, &msg);
 394                 if (!cmm_skip_blanks(msg, &msg))
 395                         return;
 396                 seconds = cmm_strtoul(msg, &msg);
 397                 cmm_skip_blanks(msg, &msg);
 398                 if (*msg == '\0')
 399                         cmm_set_timeout(pages, seconds);
 400         }
 401 }
 402 #endif
 403
 404 struct ctl_table_header *cmm_sysctl_header;
 405
 406 static int
 407 cmm_init (void)
 408 {
 409 #ifdef CONFIG_CMM_PROC
 410         cmm_sysctl_header = register_sysctl_table(cmm_dir_table, 1);
 411 #endif
 412 #ifdef CONFIG_CMM_IUCV
 413         smsg_register_callback(SMSG_PREFIX, cmm_smsg_target);
 414 #endif
 415         INIT_WORK(&cmm_thread_starter, (void *) cmm_start_thread, 0);
 416         init_waitqueue_head(&cmm_thread_wait);
 417         init_timer(&cmm_timer);
 418         return 0;
 419 }
 420
 421 static void
 422 cmm_exit(void)
 423 {
 424         cmm_free_pages(cmm_pages, &cmm_pages, &cmm_page_list);
 425         cmm_free_pages(cmm_timed_pages, &cmm_timed_pages, &cmm_timed_page_list);
 426 #ifdef CONFIG_CMM_PROC
 427         unregister_sysctl_table(cmm_sysctl_header);
 428 #endif
 429 #ifdef CONFIG_CMM_IUCV
 430         smsg_unregister_callback(SMSG_PREFIX, cmm_smsg_target);
 431 #endif
 432 }
 433
 434 module_init(cmm_init);
 435 module_exit(cmm_exit);
 436
 437 EXPORT_SYMBOL(cmm_set_pages);
 438 EXPORT_SYMBOL(cmm_get_pages);
 439 EXPORT_SYMBOL(cmm_add_timed_pages);
 440 EXPORT_SYMBOL(cmm_get_timed_pages);
 441 EXPORT_SYMBOL(cmm_set_timeout);
 442
 443 MODULE_LICENSE("GPL");