arch/s390/mm/cmm.c

   1 /*
   2  *  Collaborative memory management interface.
   3  *
   4  *    Copyright IBM Corp 2003, 2010
   5  *    Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>,
   6  *
   7  */
   8
   9 #include <linux/errno.h>
  10 #include <linux/fs.h>
  11 #include <linux/init.h>
  12 #include <linux/module.h>
  13 #include <linux/moduleparam.h>
  14 #include <linux/gfp.h>
  15 #include <linux/sched.h>
  16 #include <linux/sysctl.h>
  17 #include <linux/ctype.h>
  18 #include <linux/swap.h>
  19 #include <linux/kthread.h>
  20 #include <linux/oom.h>
  21 #include <linux/suspend.h>
  22 #include <linux/uaccess.h>
  23
  24 #include <asm/pgalloc.h>
  25 #include <asm/diag.h>
  26
  27 #ifdef CONFIG_CMM_IUCV
  28 static char *cmm_default_sender = "VMRMSVM";
  29 #endif
  30 static char *sender;
  31 module_param(sender, charp, 0400);
  32 MODULE_PARM_DESC(sender,
  33                  "Guest name that may send SMSG messages (default VMRMSVM)");
  34
  35 #include "../../../drivers/s390/net/smsgiucv.h"
  36
  37 #define CMM_NR_PAGES ((PAGE_SIZE / sizeof(unsigned long)) - 2)
  38
  39 struct cmm_page_array {
  40         struct cmm_page_array *next;
  41         unsigned long index;
  42         unsigned long pages[CMM_NR_PAGES];
  43 };
  44
  45 static long cmm_pages;
  46 static long cmm_timed_pages;
  47 static volatile long cmm_pages_target;
  48 static volatile long cmm_timed_pages_target;
  49 static long cmm_timeout_pages;
  50 static long cmm_timeout_seconds;
  51 static int cmm_suspended;
  52
  53 static struct cmm_page_array *cmm_page_list;
  54 static struct cmm_page_array *cmm_timed_page_list;
  55 static DEFINE_SPINLOCK(cmm_lock);
  56
  57 static struct task_struct *cmm_thread_ptr;
  58 static DECLARE_WAIT_QUEUE_HEAD(cmm_thread_wait);
  59
  60 static void cmm_timer_fn(struct timer_list *);
  61 static void cmm_set_timer(void);
  62 static DEFINE_TIMER(cmm_timer, cmm_timer_fn);
  63
  64 static long cmm_alloc_pages(long nr, long *counter,
  65                             struct cmm_page_array **list)
  66 {
  67         struct cmm_page_array *pa, *npa;
  68         unsigned long addr;
  69
  70         while (nr) {
  71                 addr = __get_free_page(GFP_NOIO);
  72                 if (!addr)
  73                         break;
  74                 spin_lock(&cmm_lock);
  75                 pa = *list;
  76                 if (!pa || pa->index >= CMM_NR_PAGES) {
  77                         /* Need a new page for the page list. */
  78                         spin_unlock(&cmm_lock);
  79                         npa = (struct cmm_page_array *)
  80                                 __get_free_page(GFP_NOIO);
  81                         if (!npa) {
  82                                 free_page(addr);
  83                                 break;
  84                         }
  85                         spin_lock(&cmm_lock);
  86                         pa = *list;
  87                         if (!pa || pa->index >= CMM_NR_PAGES) {
  88                                 npa->next = pa;
  89                                 npa->index = 0;
  90                                 pa = npa;
  91                                 *list = pa;
  92                         } else
  93                                 free_page((unsigned long) npa);
  94                 }
  95                 diag10_range(addr >> PAGE_SHIFT, 1);
  96                 pa->pages[pa->index++] = addr;
  97                 (*counter)++;
  98                 spin_unlock(&cmm_lock);
  99                 nr--;
 100         }
 101         return nr;
 102 }
 103
 104 static long cmm_free_pages(long nr, long *counter, struct cmm_page_array **list)
 105 {
 106         struct cmm_page_array *pa;
 107         unsigned long addr;
 108
 109         spin_lock(&cmm_lock);
 110         pa = *list;
 111         while (nr) {
 112                 if (!pa || pa->index <= 0)
 113                         break;
 114                 addr = pa->pages[--pa->index];
 115                 if (pa->index == 0) {
 116                         pa = pa->next;
 117                         free_page((unsigned long) *list);
 118                         *list = pa;
 119                 }
 120                 free_page(addr);
 121                 (*counter)--;
 122                 nr--;
 123         }
 124         spin_unlock(&cmm_lock);
 125         return nr;
 126 }
 127
 128 static int cmm_oom_notify(struct notifier_block *self,
 129                           unsigned long dummy, void *parm)
 130 {
 131         unsigned long *freed = parm;
 132         long nr = 256;
 133
 134         nr = cmm_free_pages(nr, &cmm_timed_pages, &cmm_timed_page_list);
 135         if (nr > 0)
 136                 nr = cmm_free_pages(nr, &cmm_pages, &cmm_page_list);
 137         cmm_pages_target = cmm_pages;
 138         cmm_timed_pages_target = cmm_timed_pages;
 139         *freed += 256 - nr;
 140         return NOTIFY_OK;
 141 }
 142
 143 static struct notifier_block cmm_oom_nb = {
 144         .notifier_call = cmm_oom_notify,
 145 };
 146
 147 static int 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 cmm_kick_thread(void)
 182 {
 183         wake_up(&cmm_thread_wait);
 184 }
 185
 186 static void cmm_set_timer(void)
 187 {
 188         if (cmm_timed_pages_target <= 0 || cmm_timeout_seconds <= 0) {
 189                 if (timer_pending(&cmm_timer))
 190                         del_timer(&cmm_timer);
 191                 return;
 192         }
 193         if (timer_pending(&cmm_timer)) {
 194                 if (mod_timer(&cmm_timer, jiffies + cmm_timeout_seconds*HZ))
 195                         return;
 196         }
 197         cmm_timer.expires = jiffies + cmm_timeout_seconds*HZ;
 198         add_timer(&cmm_timer);
 199 }
 200
 201 static void cmm_timer_fn(struct timer_list *unused)
 202 {
 203         long nr;
 204
 205         nr = cmm_timed_pages_target - cmm_timeout_pages;
 206         if (nr < 0)
 207                 cmm_timed_pages_target = 0;
 208         else
 209                 cmm_timed_pages_target = nr;
 210         cmm_kick_thread();
 211         cmm_set_timer();
 212 }
 213
 214 static void cmm_set_pages(long nr)
 215 {
 216         cmm_pages_target = nr;
 217         cmm_kick_thread();
 218 }
 219
 220 static long cmm_get_pages(void)
 221 {
 222         return cmm_pages;
 223 }
 224
 225 static void cmm_add_timed_pages(long nr)
 226 {
 227         cmm_timed_pages_target += nr;
 228         cmm_kick_thread();
 229 }
 230
 231 static long cmm_get_timed_pages(void)
 232 {
 233         return cmm_timed_pages;
 234 }
 235
 236 static void cmm_set_timeout(long nr, long seconds)
 237 {
 238         cmm_timeout_pages = nr;
 239         cmm_timeout_seconds = seconds;
 240         cmm_set_timer();
 241 }
 242
 243 static int cmm_skip_blanks(char *cp, char **endp)
 244 {
 245         char *str;
 246
 247         for (str = cp; *str == ' ' || *str == '\t'; str++)
 248                 ;
 249         *endp = str;
 250         return str != cp;
 251 }
 252
 253 static struct ctl_table cmm_table[];
 254
 255 static int cmm_pages_handler(struct ctl_table *ctl, int write,
 256                              void __user *buffer, size_t *lenp, loff_t *ppos)
 257 {
 258         char buf[16], *p;
 259         unsigned int len;
 260         long nr;
 261
 262         if (!*lenp || (*ppos && !write)) {
 263                 *lenp = 0;
 264                 return 0;
 265         }
 266
 267         if (write) {
 268                 len = *lenp;
 269                 if (copy_from_user(buf, buffer,
 270                                    len > sizeof(buf) ? sizeof(buf) : len))
 271                         return -EFAULT;
 272                 buf[sizeof(buf) - 1] = '\0';
 273                 cmm_skip_blanks(buf, &p);
 274                 nr = simple_strtoul(p, &p, 0);
 275                 if (ctl == &cmm_table[0])
 276                         cmm_set_pages(nr);
 277                 else
 278                         cmm_add_timed_pages(nr);
 279         } else {
 280                 if (ctl == &cmm_table[0])
 281                         nr = cmm_get_pages();
 282                 else
 283                         nr = cmm_get_timed_pages();
 284                 len = sprintf(buf, "%ld\n", nr);
 285                 if (len > *lenp)
 286                         len = *lenp;
 287                 if (copy_to_user(buffer, buf, len))
 288                         return -EFAULT;
 289         }
 290         *lenp = len;
 291         *ppos += len;
 292         return 0;
 293 }
 294
 295 static int cmm_timeout_handler(struct ctl_table *ctl, int write,
 296                                void __user *buffer, size_t *lenp, loff_t *ppos)
 297 {
 298         char buf[64], *p;
 299         long nr, seconds;
 300         unsigned int len;
 301
 302         if (!*lenp || (*ppos && !write)) {
 303                 *lenp = 0;
 304                 return 0;
 305         }
 306
 307         if (write) {
 308                 len = *lenp;
 309                 if (copy_from_user(buf, buffer,
 310                                    len > sizeof(buf) ? sizeof(buf) : len))
 311                         return -EFAULT;
 312                 buf[sizeof(buf) - 1] = '\0';
 313                 cmm_skip_blanks(buf, &p);
 314                 nr = simple_strtoul(p, &p, 0);
 315                 cmm_skip_blanks(p, &p);
 316                 seconds = simple_strtoul(p, &p, 0);
 317                 cmm_set_timeout(nr, seconds);
 318         } else {
 319                 len = sprintf(buf, "%ld %ld\n",
 320                               cmm_timeout_pages, cmm_timeout_seconds);
 321                 if (len > *lenp)
 322                         len = *lenp;
 323                 if (copy_to_user(buffer, buf, len))
 324                         return -EFAULT;
 325         }
 326         *lenp = len;
 327         *ppos += len;
 328         return 0;
 329 }
 330
 331 static struct ctl_table cmm_table[] = {
 332         {
 333                 .procname       = "cmm_pages",
 334                 .mode           = 0644,
 335                 .proc_handler   = cmm_pages_handler,
 336         },
 337         {
 338                 .procname       = "cmm_timed_pages",
 339                 .mode           = 0644,
 340                 .proc_handler   = cmm_pages_handler,
 341         },
 342         {
 343                 .procname       = "cmm_timeout",
 344                 .mode           = 0644,
 345                 .proc_handler   = cmm_timeout_handler,
 346         },
 347         { }
 348 };
 349
 350 static struct ctl_table cmm_dir_table[] = {
 351         {
 352                 .procname       = "vm",
 353                 .maxlen         = 0,
 354                 .mode           = 0555,
 355                 .child          = cmm_table,
 356         },
 357         { }
 358 };
 359
 360 #ifdef CONFIG_CMM_IUCV
 361 #define SMSG_PREFIX "CMM"
 362 static void cmm_smsg_target(const char *from, char *msg)
 363 {
 364         long nr, seconds;
 365
 366         if (strlen(sender) > 0 && strcmp(from, sender) != 0)
 367                 return;
 368         if (!cmm_skip_blanks(msg + strlen(SMSG_PREFIX), &msg))
 369                 return;
 370         if (strncmp(msg, "SHRINK", 6) == 0) {
 371                 if (!cmm_skip_blanks(msg + 6, &msg))
 372                         return;
 373                 nr = simple_strtoul(msg, &msg, 0);
 374                 cmm_skip_blanks(msg, &msg);
 375                 if (*msg == '\0')
 376                         cmm_set_pages(nr);
 377         } else if (strncmp(msg, "RELEASE", 7) == 0) {
 378                 if (!cmm_skip_blanks(msg + 7, &msg))
 379                         return;
 380                 nr = simple_strtoul(msg, &msg, 0);
 381                 cmm_skip_blanks(msg, &msg);
 382                 if (*msg == '\0')
 383                         cmm_add_timed_pages(nr);
 384         } else if (strncmp(msg, "REUSE", 5) == 0) {
 385                 if (!cmm_skip_blanks(msg + 5, &msg))
 386                         return;
 387                 nr = simple_strtoul(msg, &msg, 0);
 388                 if (!cmm_skip_blanks(msg, &msg))
 389                         return;
 390                 seconds = simple_strtoul(msg, &msg, 0);
 391                 cmm_skip_blanks(msg, &msg);
 392                 if (*msg == '\0')
 393                         cmm_set_timeout(nr, seconds);
 394         }
 395 }
 396 #endif
 397
 398 static struct ctl_table_header *cmm_sysctl_header;
 399
 400 static int cmm_suspend(void)
 401 {
 402         cmm_suspended = 1;
 403         cmm_free_pages(cmm_pages, &cmm_pages, &cmm_page_list);
 404         cmm_free_pages(cmm_timed_pages, &cmm_timed_pages, &cmm_timed_page_list);
 405         return 0;
 406 }
 407
 408 static int cmm_resume(void)
 409 {
 410         cmm_suspended = 0;
 411         cmm_kick_thread();
 412         return 0;
 413 }
 414
 415 static int cmm_power_event(struct notifier_block *this,
 416                            unsigned long event, void *ptr)
 417 {
 418         switch (event) {
 419         case PM_POST_HIBERNATION:
 420                 return cmm_resume();
 421         case PM_HIBERNATION_PREPARE:
 422                 return cmm_suspend();
 423         default:
 424                 return NOTIFY_DONE;
 425         }
 426 }
 427
 428 static struct notifier_block cmm_power_notifier = {
 429         .notifier_call = cmm_power_event,
 430 };
 431
 432 static int __init cmm_init(void)
 433 {
 434         int rc = -ENOMEM;
 435
 436         cmm_sysctl_header = register_sysctl_table(cmm_dir_table);
 437         if (!cmm_sysctl_header)
 438                 goto out_sysctl;
 439 #ifdef CONFIG_CMM_IUCV
 440         /* convert sender to uppercase characters */
 441         if (sender) {
 442                 int len = strlen(sender);
 443                 while (len--)
 444                         sender[len] = toupper(sender[len]);
 445         } else {
 446                 sender = cmm_default_sender;
 447         }
 448
 449         rc = smsg_register_callback(SMSG_PREFIX, cmm_smsg_target);
 450         if (rc < 0)
 451                 goto out_smsg;
 452 #endif
 453         rc = register_oom_notifier(&cmm_oom_nb);
 454         if (rc < 0)
 455                 goto out_oom_notify;
 456         rc = register_pm_notifier(&cmm_power_notifier);
 457         if (rc)
 458                 goto out_pm;
 459         cmm_thread_ptr = kthread_run(cmm_thread, NULL, "cmmthread");
 460         if (!IS_ERR(cmm_thread_ptr))
 461                 return 0;
 462
 463         rc = PTR_ERR(cmm_thread_ptr);
 464         unregister_pm_notifier(&cmm_power_notifier);
 465 out_pm:
 466         unregister_oom_notifier(&cmm_oom_nb);
 467 out_oom_notify:
 468 #ifdef CONFIG_CMM_IUCV
 469         smsg_unregister_callback(SMSG_PREFIX, cmm_smsg_target);
 470 out_smsg:
 471 #endif
 472         unregister_sysctl_table(cmm_sysctl_header);
 473 out_sysctl:
 474         del_timer_sync(&cmm_timer);
 475         return rc;
 476 }
 477 module_init(cmm_init);
 478
 479 static void __exit cmm_exit(void)
 480 {
 481         unregister_sysctl_table(cmm_sysctl_header);
 482 #ifdef CONFIG_CMM_IUCV
 483         smsg_unregister_callback(SMSG_PREFIX, cmm_smsg_target);
 484 #endif
 485         unregister_pm_notifier(&cmm_power_notifier);
 486         unregister_oom_notifier(&cmm_oom_nb);
 487         kthread_stop(cmm_thread_ptr);
 488         del_timer_sync(&cmm_timer);
 489         cmm_free_pages(cmm_pages, &cmm_pages, &cmm_page_list);
 490         cmm_free_pages(cmm_timed_pages, &cmm_timed_pages, &cmm_timed_page_list);
 491 }
 492 module_exit(cmm_exit);
 493
 494 MODULE_LICENSE("GPL");