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/sched.h>
  16 #include <linux/sysctl.h>
  17 #include <linux/ctype.h>
  18 #include <linux/swap.h>
  19 #include <linux/kthread.h>
  20
  21 #include <asm/pgalloc.h>
  22 #include <asm/uaccess.h>
  23
  24 static char *sender = "VMRMSVM";
  25 module_param(sender, charp, 0400);
  26 MODULE_PARM_DESC(sender,
  27                  "Guest name that may send SMSG messages (default VMRMSVM)");
  28
  29 #include "../../../drivers/s390/net/smsgiucv.h"
  30
  31 #define CMM_NR_PAGES ((PAGE_SIZE / sizeof(unsigned long)) - 2)
  32
  33 struct cmm_page_array {
  34         struct cmm_page_array *next;
  35         unsigned long index;
  36         unsigned long pages[CMM_NR_PAGES];
  37 };
  38
  39 static long cmm_pages;
  40 static long cmm_timed_pages;
  41 static volatile long cmm_pages_target;
  42 static volatile long cmm_timed_pages_target;
  43 static long cmm_timeout_pages;
  44 static long cmm_timeout_seconds;
  45
  46 static struct cmm_page_array *cmm_page_list;
  47 static struct cmm_page_array *cmm_timed_page_list;
  48 static DEFINE_SPINLOCK(cmm_lock);
  49
  50 static struct task_struct *cmm_thread_ptr;
  51 static wait_queue_head_t cmm_thread_wait;
  52 static struct timer_list cmm_timer;
  53
  54 static void cmm_timer_fn(unsigned long);
  55 static void cmm_set_timer(void);
  56
  57 static long
  58 cmm_alloc_pages(long nr, long *counter, struct cmm_page_array **list)
  59 {
  60         struct cmm_page_array *pa, *npa;
  61         unsigned long addr;
  62
  63         while (nr) {
  64                 addr = __get_free_page(GFP_NOIO);
  65                 if (!addr)
  66                         break;
  67                 spin_lock(&cmm_lock);
  68                 pa = *list;
  69                 if (!pa || pa->index >= CMM_NR_PAGES) {
  70                         /* Need a new page for the page list. */
  71                         spin_unlock(&cmm_lock);
  72                         npa = (struct cmm_page_array *)
  73                                 __get_free_page(GFP_NOIO);
  74                         if (!npa) {
  75                                 free_page(addr);
  76                                 break;
  77                         }
  78                         spin_lock(&cmm_lock);
  79                         pa = *list;
  80                         if (!pa || pa->index >= CMM_NR_PAGES) {
  81                                 npa->next = pa;
  82                                 npa->index = 0;
  83                                 pa = npa;
  84                                 *list = pa;
  85                         } else
  86                                 free_page((unsigned long) npa);
  87                 }
  88                 diag10(addr);
  89                 pa->pages[pa->index++] = addr;
  90                 (*counter)++;
  91                 spin_unlock(&cmm_lock);
  92                 nr--;
  93         }
  94         return nr;
  95 }
  96
  97 static long
  98 cmm_free_pages(long nr, long *counter, struct cmm_page_array **list)
  99 {
 100         struct cmm_page_array *pa;
 101         unsigned long addr;
 102
 103         spin_lock(&cmm_lock);
 104         pa = *list;
 105         while (nr) {
 106                 if (!pa || pa->index <= 0)
 107                         break;
 108                 addr = 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(addr);
 115                 (*counter)--;
 116                 nr--;
 117         }
 118         spin_unlock(&cmm_lock);
 119         return nr;
 120 }
 121
 122 static int cmm_oom_notify(struct notifier_block *self,
 123                           unsigned long dummy, void *parm)
 124 {
 125         unsigned long *freed = parm;
 126         long nr = 256;
 127
 128         nr = cmm_free_pages(nr, &cmm_timed_pages, &cmm_timed_page_list);
 129         if (nr > 0)
 130                 nr = cmm_free_pages(nr, &cmm_pages, &cmm_page_list);
 131         cmm_pages_target = cmm_pages;
 132         cmm_timed_pages_target = cmm_timed_pages;
 133         *freed += 256 - nr;
 134         return NOTIFY_OK;
 135 }
 136
 137 static struct notifier_block cmm_oom_nb = {
 138         .notifier_call = cmm_oom_notify
 139 };
 140
 141 static int
 142 cmm_thread(void *dummy)
 143 {
 144         int rc;
 145
 146         while (1) {
 147                 rc = wait_event_interruptible(cmm_thread_wait,
 148                         (cmm_pages != cmm_pages_target ||
 149                          cmm_timed_pages != cmm_timed_pages_target ||
 150                          kthread_should_stop()));
 151                 if (kthread_should_stop() || rc == -ERESTARTSYS) {
 152                         cmm_pages_target = cmm_pages;
 153                         cmm_timed_pages_target = cmm_timed_pages;
 154                         break;
 155                 }
 156                 if (cmm_pages_target > cmm_pages) {
 157                         if (cmm_alloc_pages(1, &cmm_pages, &cmm_page_list))
 158                                 cmm_pages_target = cmm_pages;
 159                 } else if (cmm_pages_target < cmm_pages) {
 160                         cmm_free_pages(1, &cmm_pages, &cmm_page_list);
 161                 }
 162                 if (cmm_timed_pages_target > cmm_timed_pages) {
 163                         if (cmm_alloc_pages(1, &cmm_timed_pages,
 164                                            &cmm_timed_page_list))
 165                                 cmm_timed_pages_target = cmm_timed_pages;
 166                 } else if (cmm_timed_pages_target < cmm_timed_pages) {
 167                         cmm_free_pages(1, &cmm_timed_pages,
 168                                        &cmm_timed_page_list);
 169                 }
 170                 if (cmm_timed_pages > 0 && !timer_pending(&cmm_timer))
 171                         cmm_set_timer();
 172         }
 173         return 0;
 174 }
 175
 176 static void
 177 cmm_kick_thread(void)
 178 {
 179         wake_up(&cmm_thread_wait);
 180 }
 181
 182 static void
 183 cmm_set_timer(void)
 184 {
 185         if (cmm_timed_pages_target <= 0 || cmm_timeout_seconds <= 0) {
 186                 if (timer_pending(&cmm_timer))
 187                         del_timer(&cmm_timer);
 188                 return;
 189         }
 190         if (timer_pending(&cmm_timer)) {
 191                 if (mod_timer(&cmm_timer, jiffies + cmm_timeout_seconds*HZ))
 192                         return;
 193         }
 194         cmm_timer.function = cmm_timer_fn;
 195         cmm_timer.data = 0;
 196         cmm_timer.expires = jiffies + cmm_timeout_seconds*HZ;
 197         add_timer(&cmm_timer);
 198 }
 199
 200 static void
 201 cmm_timer_fn(unsigned long ignored)
 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 void
 215 cmm_set_pages(long nr)
 216 {
 217         cmm_pages_target = nr;
 218         cmm_kick_thread();
 219 }
 220
 221 long
 222 cmm_get_pages(void)
 223 {
 224         return cmm_pages;
 225 }
 226
 227 void
 228 cmm_add_timed_pages(long nr)
 229 {
 230         cmm_timed_pages_target += nr;
 231         cmm_kick_thread();
 232 }
 233
 234 long
 235 cmm_get_timed_pages(void)
 236 {
 237         return cmm_timed_pages;
 238 }
 239
 240 void
 241 cmm_set_timeout(long nr, long seconds)
 242 {
 243         cmm_timeout_pages = nr;
 244         cmm_timeout_seconds = seconds;
 245         cmm_set_timer();
 246 }
 247
 248 static int
 249 cmm_skip_blanks(char *cp, char **endp)
 250 {
 251         char *str;
 252
 253         for (str = cp; *str == ' ' || *str == '\t'; str++);
 254         *endp = str;
 255         return str != cp;
 256 }
 257
 258 #ifdef CONFIG_CMM_PROC
 259 /* These will someday get removed. */
 260 #define VM_CMM_PAGES            1111
 261 #define VM_CMM_TIMED_PAGES      1112
 262 #define VM_CMM_TIMEOUT          1113
 263
 264 static struct ctl_table cmm_table[];
 265
 266 static int
 267 cmm_pages_handler(ctl_table *ctl, int write, struct file *filp,
 268                   void __user *buffer, size_t *lenp, loff_t *ppos)
 269 {
 270         char buf[16], *p;
 271         long nr;
 272         int len;
 273
 274         if (!*lenp || (*ppos && !write)) {
 275                 *lenp = 0;
 276                 return 0;
 277         }
 278
 279         if (write) {
 280                 len = *lenp;
 281                 if (copy_from_user(buf, buffer,
 282                                    len > sizeof(buf) ? sizeof(buf) : len))
 283                         return -EFAULT;
 284                 buf[sizeof(buf) - 1] = '\0';
 285                 cmm_skip_blanks(buf, &p);
 286                 nr = simple_strtoul(p, &p, 0);
 287                 if (ctl == &cmm_table[0])
 288                         cmm_set_pages(nr);
 289                 else
 290                         cmm_add_timed_pages(nr);
 291         } else {
 292                 if (ctl == &cmm_table[0])
 293                         nr = cmm_get_pages();
 294                 else
 295                         nr = cmm_get_timed_pages();
 296                 len = sprintf(buf, "%ld\n", nr);
 297                 if (len > *lenp)
 298                         len = *lenp;
 299                 if (copy_to_user(buffer, buf, len))
 300                         return -EFAULT;
 301         }
 302         *lenp = len;
 303         *ppos += len;
 304         return 0;
 305 }
 306
 307 static int
 308 cmm_timeout_handler(ctl_table *ctl, int write, struct file *filp,
 309                     void __user *buffer, size_t *lenp, loff_t *ppos)
 310 {
 311         char buf[64], *p;
 312         long nr, seconds;
 313         int len;
 314
 315         if (!*lenp || (*ppos && !write)) {
 316                 *lenp = 0;
 317                 return 0;
 318         }
 319
 320         if (write) {
 321                 len = *lenp;
 322                 if (copy_from_user(buf, buffer,
 323                                    len > sizeof(buf) ? sizeof(buf) : len))
 324                         return -EFAULT;
 325                 buf[sizeof(buf) - 1] = '\0';
 326                 cmm_skip_blanks(buf, &p);
 327                 nr = simple_strtoul(p, &p, 0);
 328                 cmm_skip_blanks(p, &p);
 329                 seconds = simple_strtoul(p, &p, 0);
 330                 cmm_set_timeout(nr, seconds);
 331         } else {
 332                 len = sprintf(buf, "%ld %ld\n",
 333                               cmm_timeout_pages, cmm_timeout_seconds);
 334                 if (len > *lenp)
 335                         len = *lenp;
 336                 if (copy_to_user(buffer, buf, len))
 337                         return -EFAULT;
 338         }
 339         *lenp = len;
 340         *ppos += len;
 341         return 0;
 342 }
 343
 344 static struct ctl_table cmm_table[] = {
 345         {
 346                 .ctl_name       = VM_CMM_PAGES,
 347                 .procname       = "cmm_pages",
 348                 .mode           = 0644,
 349                 .proc_handler   = &cmm_pages_handler,
 350         },
 351         {
 352                 .ctl_name       = VM_CMM_TIMED_PAGES,
 353                 .procname       = "cmm_timed_pages",
 354                 .mode           = 0644,
 355                 .proc_handler   = &cmm_pages_handler,
 356         },
 357         {
 358                 .ctl_name       = VM_CMM_TIMEOUT,
 359                 .procname       = "cmm_timeout",
 360                 .mode           = 0644,
 361                 .proc_handler   = &cmm_timeout_handler,
 362         },
 363         { .ctl_name = 0 }
 364 };
 365
 366 static struct ctl_table cmm_dir_table[] = {
 367         {
 368                 .ctl_name       = CTL_VM,
 369                 .procname       = "vm",
 370                 .maxlen         = 0,
 371                 .mode           = 0555,
 372                 .child          = cmm_table,
 373         },
 374         { .ctl_name = 0 }
 375 };
 376 #endif
 377
 378 #ifdef CONFIG_CMM_IUCV
 379 #define SMSG_PREFIX "CMM"
 380 static void
 381 cmm_smsg_target(char *from, char *msg)
 382 {
 383         long nr, seconds;
 384
 385         if (strlen(sender) > 0 && strcmp(from, sender) != 0)
 386                 return;
 387         if (!cmm_skip_blanks(msg + strlen(SMSG_PREFIX), &msg))
 388                 return;
 389         if (strncmp(msg, "SHRINK", 6) == 0) {
 390                 if (!cmm_skip_blanks(msg + 6, &msg))
 391                         return;
 392                 nr = simple_strtoul(msg, &msg, 0);
 393                 cmm_skip_blanks(msg, &msg);
 394                 if (*msg == '\0')
 395                         cmm_set_pages(nr);
 396         } else if (strncmp(msg, "RELEASE", 7) == 0) {
 397                 if (!cmm_skip_blanks(msg + 7, &msg))
 398                         return;
 399                 nr = simple_strtoul(msg, &msg, 0);
 400                 cmm_skip_blanks(msg, &msg);
 401                 if (*msg == '\0')
 402                         cmm_add_timed_pages(nr);
 403         } else if (strncmp(msg, "REUSE", 5) == 0) {
 404                 if (!cmm_skip_blanks(msg + 5, &msg))
 405                         return;
 406                 nr = simple_strtoul(msg, &msg, 0);
 407                 if (!cmm_skip_blanks(msg, &msg))
 408                         return;
 409                 seconds = simple_strtoul(msg, &msg, 0);
 410                 cmm_skip_blanks(msg, &msg);
 411                 if (*msg == '\0')
 412                         cmm_set_timeout(nr, seconds);
 413         }
 414 }
 415 #endif
 416
 417 static struct ctl_table_header *cmm_sysctl_header;
 418
 419 static int
 420 cmm_init (void)
 421 {
 422         int rc = -ENOMEM;
 423
 424 #ifdef CONFIG_CMM_PROC
 425         cmm_sysctl_header = register_sysctl_table(cmm_dir_table, 1);
 426         if (!cmm_sysctl_header)
 427                 goto out;
 428 #endif
 429 #ifdef CONFIG_CMM_IUCV
 430         rc = smsg_register_callback(SMSG_PREFIX, cmm_smsg_target);
 431         if (rc < 0)
 432                 goto out_smsg;
 433 #endif
 434         rc = register_oom_notifier(&cmm_oom_nb);
 435         if (rc < 0)
 436                 goto out_oom_notify;
 437         init_waitqueue_head(&cmm_thread_wait);
 438         init_timer(&cmm_timer);
 439         cmm_thread_ptr = kthread_run(cmm_thread, NULL, "cmmthread");
 440         rc = IS_ERR(cmm_thread_ptr) ? PTR_ERR(cmm_thread_ptr) : 0;
 441         if (!rc)
 442                 goto out;
 443         /*
 444          * kthread_create failed. undo all the stuff from above again.
 445          */
 446         unregister_oom_notifier(&cmm_oom_nb);
 447
 448 out_oom_notify:
 449 #ifdef CONFIG_CMM_IUCV
 450         smsg_unregister_callback(SMSG_PREFIX, cmm_smsg_target);
 451 out_smsg:
 452 #endif
 453 #ifdef CONFIG_CMM_PROC
 454         unregister_sysctl_table(cmm_sysctl_header);
 455 #endif
 456 out:
 457         return rc;
 458 }
 459
 460 static void
 461 cmm_exit(void)
 462 {
 463         kthread_stop(cmm_thread_ptr);
 464         unregister_oom_notifier(&cmm_oom_nb);
 465         cmm_free_pages(cmm_pages, &cmm_pages, &cmm_page_list);
 466         cmm_free_pages(cmm_timed_pages, &cmm_timed_pages, &cmm_timed_page_list);
 467 #ifdef CONFIG_CMM_PROC
 468         unregister_sysctl_table(cmm_sysctl_header);
 469 #endif
 470 #ifdef CONFIG_CMM_IUCV
 471         smsg_unregister_callback(SMSG_PREFIX, cmm_smsg_target);
 472 #endif
 473 }
 474
 475 module_init(cmm_init);
 476 module_exit(cmm_exit);
 477
 478 EXPORT_SYMBOL(cmm_set_pages);
 479 EXPORT_SYMBOL(cmm_get_pages);
 480 EXPORT_SYMBOL(cmm_add_timed_pages);
 481 EXPORT_SYMBOL(cmm_get_timed_pages);
 482 EXPORT_SYMBOL(cmm_set_timeout);
 483
 484 MODULE_LICENSE("GPL");