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