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
 260 static struct ctl_table cmm_table[];
 261
 262 static int
 263 cmm_pages_handler(ctl_table *ctl, int write, struct file *filp,
 264                   void __user *buffer, size_t *lenp, loff_t *ppos)
 265 {
 266         char buf[16], *p;
 267         long nr;
 268         int len;
 269
 270         if (!*lenp || (*ppos && !write)) {
 271                 *lenp = 0;
 272                 return 0;
 273         }
 274
 275         if (write) {
 276                 len = *lenp;
 277                 if (copy_from_user(buf, buffer,
 278                                    len > sizeof(buf) ? sizeof(buf) : len))
 279                         return -EFAULT;
 280                 buf[sizeof(buf) - 1] = '\0';
 281                 cmm_skip_blanks(buf, &p);
 282                 nr = simple_strtoul(p, &p, 0);
 283                 if (ctl == &cmm_table[0])
 284                         cmm_set_pages(nr);
 285                 else
 286                         cmm_add_timed_pages(nr);
 287         } else {
 288                 if (ctl == &cmm_table[0])
 289                         nr = cmm_get_pages();
 290                 else
 291                         nr = cmm_get_timed_pages();
 292                 len = sprintf(buf, "%ld\n", nr);
 293                 if (len > *lenp)
 294                         len = *lenp;
 295                 if (copy_to_user(buffer, buf, len))
 296                         return -EFAULT;
 297         }
 298         *lenp = len;
 299         *ppos += len;
 300         return 0;
 301 }
 302
 303 static int
 304 cmm_timeout_handler(ctl_table *ctl, int write, struct file *filp,
 305                     void __user *buffer, size_t *lenp, loff_t *ppos)
 306 {
 307         char buf[64], *p;
 308         long nr, seconds;
 309         int len;
 310
 311         if (!*lenp || (*ppos && !write)) {
 312                 *lenp = 0;
 313                 return 0;
 314         }
 315
 316         if (write) {
 317                 len = *lenp;
 318                 if (copy_from_user(buf, buffer,
 319                                    len > sizeof(buf) ? sizeof(buf) : len))
 320                         return -EFAULT;
 321                 buf[sizeof(buf) - 1] = '\0';
 322                 cmm_skip_blanks(buf, &p);
 323                 nr = simple_strtoul(p, &p, 0);
 324                 cmm_skip_blanks(p, &p);
 325                 seconds = simple_strtoul(p, &p, 0);
 326                 cmm_set_timeout(nr, seconds);
 327         } else {
 328                 len = sprintf(buf, "%ld %ld\n",
 329                               cmm_timeout_pages, cmm_timeout_seconds);
 330                 if (len > *lenp)
 331                         len = *lenp;
 332                 if (copy_to_user(buffer, buf, len))
 333                         return -EFAULT;
 334         }
 335         *lenp = len;
 336         *ppos += len;
 337         return 0;
 338 }
 339
 340 static struct ctl_table cmm_table[] = {
 341         {
 342                 .ctl_name       = VM_CMM_PAGES,
 343                 .procname       = "cmm_pages",
 344                 .mode           = 0644,
 345                 .proc_handler   = &cmm_pages_handler,
 346         },
 347         {
 348                 .ctl_name       = VM_CMM_TIMED_PAGES,
 349                 .procname       = "cmm_timed_pages",
 350                 .mode           = 0644,
 351                 .proc_handler   = &cmm_pages_handler,
 352         },
 353         {
 354                 .ctl_name       = VM_CMM_TIMEOUT,
 355                 .procname       = "cmm_timeout",
 356                 .mode           = 0644,
 357                 .proc_handler   = &cmm_timeout_handler,
 358         },
 359         { .ctl_name = 0 }
 360 };
 361
 362 static struct ctl_table cmm_dir_table[] = {
 363         {
 364                 .ctl_name       = CTL_VM,
 365                 .procname       = "vm",
 366                 .maxlen         = 0,
 367                 .mode           = 0555,
 368                 .child          = cmm_table,
 369         },
 370         { .ctl_name = 0 }
 371 };
 372 #endif
 373
 374 #ifdef CONFIG_CMM_IUCV
 375 #define SMSG_PREFIX "CMM"
 376 static void
 377 cmm_smsg_target(char *from, char *msg)
 378 {
 379         long nr, seconds;
 380
 381         if (strlen(sender) > 0 && strcmp(from, sender) != 0)
 382                 return;
 383         if (!cmm_skip_blanks(msg + strlen(SMSG_PREFIX), &msg))
 384                 return;
 385         if (strncmp(msg, "SHRINK", 6) == 0) {
 386                 if (!cmm_skip_blanks(msg + 6, &msg))
 387                         return;
 388                 nr = simple_strtoul(msg, &msg, 0);
 389                 cmm_skip_blanks(msg, &msg);
 390                 if (*msg == '\0')
 391                         cmm_set_pages(nr);
 392         } else if (strncmp(msg, "RELEASE", 7) == 0) {
 393                 if (!cmm_skip_blanks(msg + 7, &msg))
 394                         return;
 395                 nr = simple_strtoul(msg, &msg, 0);
 396                 cmm_skip_blanks(msg, &msg);
 397                 if (*msg == '\0')
 398                         cmm_add_timed_pages(nr);
 399         } else if (strncmp(msg, "REUSE", 5) == 0) {
 400                 if (!cmm_skip_blanks(msg + 5, &msg))
 401                         return;
 402                 nr = simple_strtoul(msg, &msg, 0);
 403                 if (!cmm_skip_blanks(msg, &msg))
 404                         return;
 405                 seconds = simple_strtoul(msg, &msg, 0);
 406                 cmm_skip_blanks(msg, &msg);
 407                 if (*msg == '\0')
 408                         cmm_set_timeout(nr, seconds);
 409         }
 410 }
 411 #endif
 412
 413 static struct ctl_table_header *cmm_sysctl_header;
 414
 415 static int
 416 cmm_init (void)
 417 {
 418         int rc = -ENOMEM;
 419
 420 #ifdef CONFIG_CMM_PROC
 421         cmm_sysctl_header = register_sysctl_table(cmm_dir_table);
 422         if (!cmm_sysctl_header)
 423                 goto out;
 424 #endif
 425 #ifdef CONFIG_CMM_IUCV
 426         rc = smsg_register_callback(SMSG_PREFIX, cmm_smsg_target);
 427         if (rc < 0)
 428                 goto out_smsg;
 429 #endif
 430         rc = register_oom_notifier(&cmm_oom_nb);
 431         if (rc < 0)
 432                 goto out_oom_notify;
 433         init_waitqueue_head(&cmm_thread_wait);
 434         init_timer(&cmm_timer);
 435         cmm_thread_ptr = kthread_run(cmm_thread, NULL, "cmmthread");
 436         rc = IS_ERR(cmm_thread_ptr) ? PTR_ERR(cmm_thread_ptr) : 0;
 437         if (!rc)
 438                 goto out;
 439         /*
 440          * kthread_create failed. undo all the stuff from above again.
 441          */
 442         unregister_oom_notifier(&cmm_oom_nb);
 443
 444 out_oom_notify:
 445 #ifdef CONFIG_CMM_IUCV
 446         smsg_unregister_callback(SMSG_PREFIX, cmm_smsg_target);
 447 out_smsg:
 448 #endif
 449 #ifdef CONFIG_CMM_PROC
 450         unregister_sysctl_table(cmm_sysctl_header);
 451 #endif
 452 out:
 453         return rc;
 454 }
 455
 456 static void
 457 cmm_exit(void)
 458 {
 459         kthread_stop(cmm_thread_ptr);
 460         unregister_oom_notifier(&cmm_oom_nb);
 461         cmm_free_pages(cmm_pages, &cmm_pages, &cmm_page_list);
 462         cmm_free_pages(cmm_timed_pages, &cmm_timed_pages, &cmm_timed_page_list);
 463 #ifdef CONFIG_CMM_PROC
 464         unregister_sysctl_table(cmm_sysctl_header);
 465 #endif
 466 #ifdef CONFIG_CMM_IUCV
 467         smsg_unregister_callback(SMSG_PREFIX, cmm_smsg_target);
 468 #endif
 469 }
 470
 471 module_init(cmm_init);
 472 module_exit(cmm_exit);
 473
 474 EXPORT_SYMBOL(cmm_set_pages);
 475 EXPORT_SYMBOL(cmm_get_pages);
 476 EXPORT_SYMBOL(cmm_add_timed_pages);
 477 EXPORT_SYMBOL(cmm_get_timed_pages);
 478 EXPORT_SYMBOL(cmm_set_timeout);
 479
 480 MODULE_LICENSE("GPL");