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/errno.h>
  12 #include <linux/fs.h>
  13 #include <linux/init.h>
  14 #include <linux/module.h>
  15 #include <linux/gfp.h>
  16 #include <linux/sched.h>
  17 #include <linux/sysctl.h>
  18 #include <linux/ctype.h>
  19 #include <linux/swap.h>
  20 #include <linux/kthread.h>
  21 #include <linux/oom.h>
  22 #include <linux/suspend.h>
  23
  24 #include <asm/pgalloc.h>
  25 #include <asm/uaccess.h>
  26 #include <asm/diag.h>
  27
  28 static char *sender = "VMRMSVM";
  29 module_param(sender, charp, 0400);
  30 MODULE_PARM_DESC(sender,
  31                  "Guest name that may send SMSG messages (default VMRMSVM)");
  32
  33 #include "../../../drivers/s390/net/smsgiucv.h"
  34
  35 #define CMM_NR_PAGES ((PAGE_SIZE / sizeof(unsigned long)) - 2)
  36
  37 struct cmm_page_array {
  38         struct cmm_page_array *next;
  39         unsigned long index;
  40         unsigned long pages[CMM_NR_PAGES];
  41 };
  42
  43 static long cmm_pages;
  44 static long cmm_timed_pages;
  45 static volatile long cmm_pages_target;
  46 static volatile long cmm_timed_pages_target;
  47 static long cmm_timeout_pages;
  48 static long cmm_timeout_seconds;
  49 static int cmm_suspended;
  50
  51 static struct cmm_page_array *cmm_page_list;
  52 static struct cmm_page_array *cmm_timed_page_list;
  53 static DEFINE_SPINLOCK(cmm_lock);
  54
  55 static struct task_struct *cmm_thread_ptr;
  56 static wait_queue_head_t cmm_thread_wait;
  57 static struct timer_list cmm_timer;
  58
  59 static void cmm_timer_fn(unsigned long);
  60 static void cmm_set_timer(void);
  61
  62 static long
  63 cmm_alloc_pages(long nr, long *counter, struct cmm_page_array **list)
  64 {
  65         struct cmm_page_array *pa, *npa;
  66         unsigned long addr;
  67
  68         while (nr) {
  69                 addr = __get_free_page(GFP_NOIO);
  70                 if (!addr)
  71                         break;
  72                 spin_lock(&cmm_lock);
  73                 pa = *list;
  74                 if (!pa || pa->index >= CMM_NR_PAGES) {
  75                         /* Need a new page for the page list. */
  76                         spin_unlock(&cmm_lock);
  77                         npa = (struct cmm_page_array *)
  78                                 __get_free_page(GFP_NOIO);
  79                         if (!npa) {
  80                                 free_page(addr);
  81                                 break;
  82                         }
  83                         spin_lock(&cmm_lock);
  84                         pa = *list;
  85                         if (!pa || pa->index >= CMM_NR_PAGES) {
  86                                 npa->next = pa;
  87                                 npa->index = 0;
  88                                 pa = npa;
  89                                 *list = pa;
  90                         } else
  91                                 free_page((unsigned long) npa);
  92                 }
  93                 diag10(addr);
  94                 pa->pages[pa->index++] = addr;
  95                 (*counter)++;
  96                 spin_unlock(&cmm_lock);
  97                 nr--;
  98         }
  99         return nr;
 100 }
 101
 102 static long
 103 cmm_free_pages(long nr, long *counter, struct cmm_page_array **list)
 104 {
 105         struct cmm_page_array *pa;
 106         unsigned long addr;
 107
 108         spin_lock(&cmm_lock);
 109         pa = *list;
 110         while (nr) {
 111                 if (!pa || pa->index <= 0)
 112                         break;
 113                 addr = pa->pages[--pa->index];
 114                 if (pa->index == 0) {
 115                         pa = pa->next;
 116                         free_page((unsigned long) *list);
 117                         *list = pa;
 118                 }
 119                 free_page(addr);
 120                 (*counter)--;
 121                 nr--;
 122         }
 123         spin_unlock(&cmm_lock);
 124         return nr;
 125 }
 126
 127 static int cmm_oom_notify(struct notifier_block *self,
 128                           unsigned long dummy, void *parm)
 129 {
 130         unsigned long *freed = parm;
 131         long nr = 256;
 132
 133         nr = cmm_free_pages(nr, &cmm_timed_pages, &cmm_timed_page_list);
 134         if (nr > 0)
 135                 nr = cmm_free_pages(nr, &cmm_pages, &cmm_page_list);
 136         cmm_pages_target = cmm_pages;
 137         cmm_timed_pages_target = cmm_timed_pages;
 138         *freed += 256 - nr;
 139         return NOTIFY_OK;
 140 }
 141
 142 static struct notifier_block cmm_oom_nb = {
 143         .notifier_call = cmm_oom_notify
 144 };
 145
 146 static int
 147 cmm_thread(void *dummy)
 148 {
 149         int rc;
 150
 151         while (1) {
 152                 rc = wait_event_interruptible(cmm_thread_wait,
 153                         (!cmm_suspended && (cmm_pages != cmm_pages_target ||
 154                          cmm_timed_pages != cmm_timed_pages_target)) ||
 155                          kthread_should_stop());
 156                 if (kthread_should_stop() || rc == -ERESTARTSYS) {
 157                         cmm_pages_target = cmm_pages;
 158                         cmm_timed_pages_target = cmm_timed_pages;
 159                         break;
 160                 }
 161                 if (cmm_pages_target > cmm_pages) {
 162                         if (cmm_alloc_pages(1, &cmm_pages, &cmm_page_list))
 163                                 cmm_pages_target = cmm_pages;
 164                 } else if (cmm_pages_target < cmm_pages) {
 165                         cmm_free_pages(1, &cmm_pages, &cmm_page_list);
 166                 }
 167                 if (cmm_timed_pages_target > cmm_timed_pages) {
 168                         if (cmm_alloc_pages(1, &cmm_timed_pages,
 169                                            &cmm_timed_page_list))
 170                                 cmm_timed_pages_target = cmm_timed_pages;
 171                 } else if (cmm_timed_pages_target < cmm_timed_pages) {
 172                         cmm_free_pages(1, &cmm_timed_pages,
 173                                        &cmm_timed_page_list);
 174                 }
 175                 if (cmm_timed_pages > 0 && !timer_pending(&cmm_timer))
 176                         cmm_set_timer();
 177         }
 178         return 0;
 179 }
 180
 181 static void
 182 cmm_kick_thread(void)
 183 {
 184         wake_up(&cmm_thread_wait);
 185 }
 186
 187 static void
 188 cmm_set_timer(void)
 189 {
 190         if (cmm_timed_pages_target <= 0 || cmm_timeout_seconds <= 0) {
 191                 if (timer_pending(&cmm_timer))
 192                         del_timer(&cmm_timer);
 193                 return;
 194         }
 195         if (timer_pending(&cmm_timer)) {
 196                 if (mod_timer(&cmm_timer, jiffies + cmm_timeout_seconds*HZ))
 197                         return;
 198         }
 199         cmm_timer.function = cmm_timer_fn;
 200         cmm_timer.data = 0;
 201         cmm_timer.expires = jiffies + cmm_timeout_seconds*HZ;
 202         add_timer(&cmm_timer);
 203 }
 204
 205 static void
 206 cmm_timer_fn(unsigned long ignored)
 207 {
 208         long nr;
 209
 210         nr = cmm_timed_pages_target - cmm_timeout_pages;
 211         if (nr < 0)
 212                 cmm_timed_pages_target = 0;
 213         else
 214                 cmm_timed_pages_target = nr;
 215         cmm_kick_thread();
 216         cmm_set_timer();
 217 }
 218
 219 void
 220 cmm_set_pages(long nr)
 221 {
 222         cmm_pages_target = nr;
 223         cmm_kick_thread();
 224 }
 225
 226 long
 227 cmm_get_pages(void)
 228 {
 229         return cmm_pages;
 230 }
 231
 232 void
 233 cmm_add_timed_pages(long nr)
 234 {
 235         cmm_timed_pages_target += nr;
 236         cmm_kick_thread();
 237 }
 238
 239 long
 240 cmm_get_timed_pages(void)
 241 {
 242         return cmm_timed_pages;
 243 }
 244
 245 void
 246 cmm_set_timeout(long nr, long seconds)
 247 {
 248         cmm_timeout_pages = nr;
 249         cmm_timeout_seconds = seconds;
 250         cmm_set_timer();
 251 }
 252
 253 static int
 254 cmm_skip_blanks(char *cp, char **endp)
 255 {
 256         char *str;
 257
 258         for (str = cp; *str == ' ' || *str == '\t'; str++);
 259         *endp = str;
 260         return str != cp;
 261 }
 262
 263 #ifdef CONFIG_CMM_PROC
 264
 265 static struct ctl_table cmm_table[];
 266
 267 static int
 268 cmm_pages_handler(ctl_table *ctl, int write,
 269                   void __user *buffer, size_t *lenp, loff_t *ppos)
 270 {
 271         char buf[16], *p;
 272         long nr;
 273         int len;
 274
 275         if (!*lenp || (*ppos && !write)) {
 276                 *lenp = 0;
 277                 return 0;
 278         }
 279
 280         if (write) {
 281                 len = *lenp;
 282                 if (copy_from_user(buf, buffer,
 283                                    len > sizeof(buf) ? sizeof(buf) : len))
 284                         return -EFAULT;
 285                 buf[sizeof(buf) - 1] = '\0';
 286                 cmm_skip_blanks(buf, &p);
 287                 nr = simple_strtoul(p, &p, 0);
 288                 if (ctl == &cmm_table[0])
 289                         cmm_set_pages(nr);
 290                 else
 291                         cmm_add_timed_pages(nr);
 292         } else {
 293                 if (ctl == &cmm_table[0])
 294                         nr = cmm_get_pages();
 295                 else
 296                         nr = cmm_get_timed_pages();
 297                 len = sprintf(buf, "%ld\n", nr);
 298                 if (len > *lenp)
 299                         len = *lenp;
 300                 if (copy_to_user(buffer, buf, len))
 301                         return -EFAULT;
 302         }
 303         *lenp = len;
 304         *ppos += len;
 305         return 0;
 306 }
 307
 308 static int
 309 cmm_timeout_handler(ctl_table *ctl, int write,
 310                     void __user *buffer, size_t *lenp, loff_t *ppos)
 311 {
 312         char buf[64], *p;
 313         long nr, seconds;
 314         int len;
 315
 316         if (!*lenp || (*ppos && !write)) {
 317                 *lenp = 0;
 318                 return 0;
 319         }
 320
 321         if (write) {
 322                 len = *lenp;
 323                 if (copy_from_user(buf, buffer,
 324                                    len > sizeof(buf) ? sizeof(buf) : len))
 325                         return -EFAULT;
 326                 buf[sizeof(buf) - 1] = '\0';
 327                 cmm_skip_blanks(buf, &p);
 328                 nr = simple_strtoul(p, &p, 0);
 329                 cmm_skip_blanks(p, &p);
 330                 seconds = simple_strtoul(p, &p, 0);
 331                 cmm_set_timeout(nr, seconds);
 332         } else {
 333                 len = sprintf(buf, "%ld %ld\n",
 334                               cmm_timeout_pages, cmm_timeout_seconds);
 335                 if (len > *lenp)
 336                         len = *lenp;
 337                 if (copy_to_user(buffer, buf, len))
 338                         return -EFAULT;
 339         }
 340         *lenp = len;
 341         *ppos += len;
 342         return 0;
 343 }
 344
 345 static struct ctl_table cmm_table[] = {
 346         {
 347                 .procname       = "cmm_pages",
 348                 .mode           = 0644,
 349                 .proc_handler   = cmm_pages_handler,
 350         },
 351         {
 352                 .procname       = "cmm_timed_pages",
 353                 .mode           = 0644,
 354                 .proc_handler   = cmm_pages_handler,
 355         },
 356         {
 357                 .procname       = "cmm_timeout",
 358                 .mode           = 0644,
 359                 .proc_handler   = cmm_timeout_handler,
 360         },
 361         { }
 362 };
 363
 364 static struct ctl_table cmm_dir_table[] = {
 365         {
 366                 .procname       = "vm",
 367                 .maxlen         = 0,
 368                 .mode           = 0555,
 369                 .child          = cmm_table,
 370         },
 371         { }
 372 };
 373 #endif
 374
 375 #ifdef CONFIG_CMM_IUCV
 376 #define SMSG_PREFIX "CMM"
 377 static void
 378 cmm_smsg_target(const char *from, char *msg)
 379 {
 380         long nr, seconds;
 381
 382         if (strlen(sender) > 0 && strcmp(from, sender) != 0)
 383                 return;
 384         if (!cmm_skip_blanks(msg + strlen(SMSG_PREFIX), &msg))
 385                 return;
 386         if (strncmp(msg, "SHRINK", 6) == 0) {
 387                 if (!cmm_skip_blanks(msg + 6, &msg))
 388                         return;
 389                 nr = simple_strtoul(msg, &msg, 0);
 390                 cmm_skip_blanks(msg, &msg);
 391                 if (*msg == '\0')
 392                         cmm_set_pages(nr);
 393         } else if (strncmp(msg, "RELEASE", 7) == 0) {
 394                 if (!cmm_skip_blanks(msg + 7, &msg))
 395                         return;
 396                 nr = simple_strtoul(msg, &msg, 0);
 397                 cmm_skip_blanks(msg, &msg);
 398                 if (*msg == '\0')
 399                         cmm_add_timed_pages(nr);
 400         } else if (strncmp(msg, "REUSE", 5) == 0) {
 401                 if (!cmm_skip_blanks(msg + 5, &msg))
 402                         return;
 403                 nr = simple_strtoul(msg, &msg, 0);
 404                 if (!cmm_skip_blanks(msg, &msg))
 405                         return;
 406                 seconds = simple_strtoul(msg, &msg, 0);
 407                 cmm_skip_blanks(msg, &msg);
 408                 if (*msg == '\0')
 409                         cmm_set_timeout(nr, seconds);
 410         }
 411 }
 412 #endif
 413
 414 static struct ctl_table_header *cmm_sysctl_header;
 415
 416 static int cmm_suspend(void)
 417 {
 418         cmm_suspended = 1;
 419         cmm_free_pages(cmm_pages, &cmm_pages, &cmm_page_list);
 420         cmm_free_pages(cmm_timed_pages, &cmm_timed_pages, &cmm_timed_page_list);
 421         return 0;
 422 }
 423
 424 static int cmm_resume(void)
 425 {
 426         cmm_suspended = 0;
 427         cmm_kick_thread();
 428         return 0;
 429 }
 430
 431 static int cmm_power_event(struct notifier_block *this,
 432                            unsigned long event, void *ptr)
 433 {
 434         switch (event) {
 435         case PM_POST_HIBERNATION:
 436                 return cmm_resume();
 437         case PM_HIBERNATION_PREPARE:
 438                 return cmm_suspend();
 439         default:
 440                 return NOTIFY_DONE;
 441         }
 442 }
 443
 444 static struct notifier_block cmm_power_notifier = {
 445         .notifier_call = cmm_power_event,
 446 };
 447
 448 static int
 449 cmm_init (void)
 450 {
 451         int rc = -ENOMEM;
 452
 453 #ifdef CONFIG_CMM_PROC
 454         cmm_sysctl_header = register_sysctl_table(cmm_dir_table);
 455         if (!cmm_sysctl_header)
 456                 goto out_sysctl;
 457 #endif
 458 #ifdef CONFIG_CMM_IUCV
 459         rc = smsg_register_callback(SMSG_PREFIX, cmm_smsg_target);
 460         if (rc < 0)
 461                 goto out_smsg;
 462 #endif
 463         rc = register_oom_notifier(&cmm_oom_nb);
 464         if (rc < 0)
 465                 goto out_oom_notify;
 466         rc = register_pm_notifier(&cmm_power_notifier);
 467         if (rc)
 468                 goto out_pm;
 469         init_waitqueue_head(&cmm_thread_wait);
 470         init_timer(&cmm_timer);
 471         cmm_thread_ptr = kthread_run(cmm_thread, NULL, "cmmthread");
 472         rc = IS_ERR(cmm_thread_ptr) ? PTR_ERR(cmm_thread_ptr) : 0;
 473         if (rc)
 474                 goto out_kthread;
 475         return 0;
 476
 477 out_kthread:
 478         unregister_pm_notifier(&cmm_power_notifier);
 479 out_pm:
 480         unregister_oom_notifier(&cmm_oom_nb);
 481 out_oom_notify:
 482 #ifdef CONFIG_CMM_IUCV
 483         smsg_unregister_callback(SMSG_PREFIX, cmm_smsg_target);
 484 out_smsg:
 485 #endif
 486 #ifdef CONFIG_CMM_PROC
 487         unregister_sysctl_table(cmm_sysctl_header);
 488 out_sysctl:
 489 #endif
 490         return rc;
 491 }
 492
 493 static void
 494 cmm_exit(void)
 495 {
 496         kthread_stop(cmm_thread_ptr);
 497         unregister_pm_notifier(&cmm_power_notifier);
 498         unregister_oom_notifier(&cmm_oom_nb);
 499         cmm_free_pages(cmm_pages, &cmm_pages, &cmm_page_list);
 500         cmm_free_pages(cmm_timed_pages, &cmm_timed_pages, &cmm_timed_page_list);
 501 #ifdef CONFIG_CMM_PROC
 502         unregister_sysctl_table(cmm_sysctl_header);
 503 #endif
 504 #ifdef CONFIG_CMM_IUCV
 505         smsg_unregister_callback(SMSG_PREFIX, cmm_smsg_target);
 506 #endif
 507 }
 508
 509 module_init(cmm_init);
 510 module_exit(cmm_exit);
 511
 512 EXPORT_SYMBOL(cmm_set_pages);
 513 EXPORT_SYMBOL(cmm_get_pages);
 514 EXPORT_SYMBOL(cmm_add_timed_pages);
 515 EXPORT_SYMBOL(cmm_get_timed_pages);
 516 EXPORT_SYMBOL(cmm_set_timeout);
 517
 518 MODULE_LICENSE("GPL");