arch/s390/mm/cmm.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  Collaborative memory management interface.
   4  *
   5  *    Copyright IBM Corp 2003, 2010
   6  *    Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>,
   7  *
   8  */
   9
  10 #include <linux/errno.h>
  11 #include <linux/fs.h>
  12 #include <linux/init.h>
  13 #include <linux/module.h>
  14 #include <linux/moduleparam.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 #include <linux/uaccess.h>
  24
  25 #include <asm/pgalloc.h>
  26 #include <asm/diag.h>
  27
  28 #ifdef CONFIG_CMM_IUCV
  29 static char *cmm_default_sender = "VMRMSVM";
  30 #endif
  31 static char *sender;
  32 module_param(sender, charp, 0400);
  33 MODULE_PARM_DESC(sender,
  34                  "Guest name that may send SMSG messages (default VMRMSVM)");
  35
  36 #include "../../../drivers/s390/net/smsgiucv.h"
  37
  38 #define CMM_NR_PAGES ((PAGE_SIZE / sizeof(unsigned long)) - 2)
  39
  40 struct cmm_page_array {
  41         struct cmm_page_array *next;
  42         unsigned long index;
  43         unsigned long pages[CMM_NR_PAGES];
  44 };
  45
  46 static long cmm_pages;
  47 static long cmm_timed_pages;
  48 static volatile long cmm_pages_target;
  49 static volatile long cmm_timed_pages_target;
  50 static long cmm_timeout_pages;
  51 static long cmm_timeout_seconds;
  52 static int cmm_suspended;
  53
  54 static struct cmm_page_array *cmm_page_list;
  55 static struct cmm_page_array *cmm_timed_page_list;
  56 static DEFINE_SPINLOCK(cmm_lock);
  57
  58 static struct task_struct *cmm_thread_ptr;
  59 static DECLARE_WAIT_QUEUE_HEAD(cmm_thread_wait);
  60
  61 static void cmm_timer_fn(struct timer_list *);
  62 static void cmm_set_timer(void);
  63 static DEFINE_TIMER(cmm_timer, cmm_timer_fn);
  64
  65 static long cmm_alloc_pages(long nr, long *counter,
  66                             struct cmm_page_array **list)
  67 {
  68         struct cmm_page_array *pa, *npa;
  69         unsigned long addr;
  70
  71         while (nr) {
  72                 addr = __get_free_page(GFP_NOIO);
  73                 if (!addr)
  74                         break;
  75                 spin_lock(&cmm_lock);
  76                 pa = *list;
  77                 if (!pa || pa->index >= CMM_NR_PAGES) {
  78                         /* Need a new page for the page list. */
  79                         spin_unlock(&cmm_lock);
  80                         npa = (struct cmm_page_array *)
  81                                 __get_free_page(GFP_NOIO);
  82                         if (!npa) {
  83                                 free_page(addr);
  84                                 break;
  85                         }
  86                         spin_lock(&cmm_lock);
  87                         pa = *list;
  88                         if (!pa || pa->index >= CMM_NR_PAGES) {
  89                                 npa->next = pa;
  90                                 npa->index = 0;
  91                                 pa = npa;
  92                                 *list = pa;
  93                         } else
  94                                 free_page((unsigned long) npa);
  95                 }
  96                 diag10_range(addr >> PAGE_SHIFT, 1);
  97                 pa->pages[pa->index++] = addr;
  98                 (*counter)++;
  99                 spin_unlock(&cmm_lock);
 100                 nr--;
 101         }
 102         return nr;
 103 }
 104
 105 static long cmm_free_pages(long nr, long *counter, struct cmm_page_array **list)
 106 {
 107         struct cmm_page_array *pa;
 108         unsigned long addr;
 109
 110         spin_lock(&cmm_lock);
 111         pa = *list;
 112         while (nr) {
 113                 if (!pa || pa->index <= 0)
 114                         break;
 115                 addr = pa->pages[--pa->index];
 116                 if (pa->index == 0) {
 117                         pa = pa->next;
 118                         free_page((unsigned long) *list);
 119                         *list = pa;
 120                 }
 121                 free_page(addr);
 122                 (*counter)--;
 123                 nr--;
 124         }
 125         spin_unlock(&cmm_lock);
 126         return nr;
 127 }
 128
 129 static int cmm_oom_notify(struct notifier_block *self,
 130                           unsigned long dummy, void *parm)
 131 {
 132         unsigned long *freed = parm;
 133         long nr = 256;
 134
 135         nr = cmm_free_pages(nr, &cmm_timed_pages, &cmm_timed_page_list);
 136         if (nr > 0)
 137                 nr = cmm_free_pages(nr, &cmm_pages, &cmm_page_list);
 138         cmm_pages_target = cmm_pages;
 139         cmm_timed_pages_target = cmm_timed_pages;
 140         *freed += 256 - nr;
 141         return NOTIFY_OK;
 142 }
 143
 144 static struct notifier_block cmm_oom_nb = {
 145         .notifier_call = cmm_oom_notify,
 146 };
 147
 148 static int cmm_thread(void *dummy)
 149 {
 150         int rc;
 151
 152         while (1) {
 153                 rc = wait_event_interruptible(cmm_thread_wait,
 154                         (!cmm_suspended && (cmm_pages != cmm_pages_target ||
 155                          cmm_timed_pages != cmm_timed_pages_target)) ||
 156                          kthread_should_stop());
 157                 if (kthread_should_stop() || rc == -ERESTARTSYS) {
 158                         cmm_pages_target = cmm_pages;
 159                         cmm_timed_pages_target = cmm_timed_pages;
 160                         break;
 161                 }
 162                 if (cmm_pages_target > cmm_pages) {
 163                         if (cmm_alloc_pages(1, &cmm_pages, &cmm_page_list))
 164                                 cmm_pages_target = cmm_pages;
 165                 } else if (cmm_pages_target < cmm_pages) {
 166                         cmm_free_pages(1, &cmm_pages, &cmm_page_list);
 167                 }
 168                 if (cmm_timed_pages_target > cmm_timed_pages) {
 169                         if (cmm_alloc_pages(1, &cmm_timed_pages,
 170                                            &cmm_timed_page_list))
 171                                 cmm_timed_pages_target = cmm_timed_pages;
 172                 } else if (cmm_timed_pages_target < cmm_timed_pages) {
 173                         cmm_free_pages(1, &cmm_timed_pages,
 174                                        &cmm_timed_page_list);
 175                 }
 176                 if (cmm_timed_pages > 0 && !timer_pending(&cmm_timer))
 177                         cmm_set_timer();
 178         }
 179         return 0;
 180 }
 181
 182 static void cmm_kick_thread(void)
 183 {
 184         wake_up(&cmm_thread_wait);
 185 }
 186
 187 static void cmm_set_timer(void)
 188 {
 189         if (cmm_timed_pages_target <= 0 || cmm_timeout_seconds <= 0) {
 190                 if (timer_pending(&cmm_timer))
 191                         del_timer(&cmm_timer);
 192                 return;
 193         }
 194         mod_timer(&cmm_timer, jiffies + cmm_timeout_seconds * HZ);
 195 }
 196
 197 static void cmm_timer_fn(struct timer_list *unused)
 198 {
 199         long nr;
 200
 201         nr = cmm_timed_pages_target - cmm_timeout_pages;
 202         if (nr < 0)
 203                 cmm_timed_pages_target = 0;
 204         else
 205                 cmm_timed_pages_target = nr;
 206         cmm_kick_thread();
 207         cmm_set_timer();
 208 }
 209
 210 static void cmm_set_pages(long nr)
 211 {
 212         cmm_pages_target = nr;
 213         cmm_kick_thread();
 214 }
 215
 216 static long cmm_get_pages(void)
 217 {
 218         return cmm_pages;
 219 }
 220
 221 static void cmm_add_timed_pages(long nr)
 222 {
 223         cmm_timed_pages_target += nr;
 224         cmm_kick_thread();
 225 }
 226
 227 static long cmm_get_timed_pages(void)
 228 {
 229         return cmm_timed_pages;
 230 }
 231
 232 static void cmm_set_timeout(long nr, long seconds)
 233 {
 234         cmm_timeout_pages = nr;
 235         cmm_timeout_seconds = seconds;
 236         cmm_set_timer();
 237 }
 238
 239 static int cmm_skip_blanks(char *cp, char **endp)
 240 {
 241         char *str;
 242
 243         for (str = cp; *str == ' ' || *str == '\t'; str++)
 244                 ;
 245         *endp = str;
 246         return str != cp;
 247 }
 248
 249 static int cmm_pages_handler(struct ctl_table *ctl, int write,
 250                              void __user *buffer, size_t *lenp, loff_t *ppos)
 251 {
 252         long nr = cmm_get_pages();
 253         struct ctl_table ctl_entry = {
 254                 .procname       = ctl->procname,
 255                 .data           = &nr,
 256                 .maxlen         = sizeof(long),
 257         };
 258         int rc;
 259
 260         rc = proc_doulongvec_minmax(&ctl_entry, write, buffer, lenp, ppos);
 261         if (rc < 0 || !write)
 262                 return rc;
 263
 264         cmm_set_pages(nr);
 265         return 0;
 266 }
 267
 268 static int cmm_timed_pages_handler(struct ctl_table *ctl, int write,
 269                                    void __user *buffer, size_t *lenp,
 270                                    loff_t *ppos)
 271 {
 272         long nr = cmm_get_timed_pages();
 273         struct ctl_table ctl_entry = {
 274                 .procname       = ctl->procname,
 275                 .data           = &nr,
 276                 .maxlen         = sizeof(long),
 277         };
 278         int rc;
 279
 280         rc = proc_doulongvec_minmax(&ctl_entry, write, buffer, lenp, ppos);
 281         if (rc < 0 || !write)
 282                 return rc;
 283
 284         cmm_add_timed_pages(nr);
 285         return 0;
 286 }
 287
 288 static int cmm_timeout_handler(struct ctl_table *ctl, int write,
 289                                void __user *buffer, size_t *lenp, loff_t *ppos)
 290 {
 291         char buf[64], *p;
 292         long nr, seconds;
 293         unsigned int len;
 294
 295         if (!*lenp || (*ppos && !write)) {
 296                 *lenp = 0;
 297                 return 0;
 298         }
 299
 300         if (write) {
 301                 len = min(*lenp, sizeof(buf));
 302                 if (copy_from_user(buf, buffer, len))
 303                         return -EFAULT;
 304                 buf[len - 1] = '\0';
 305                 cmm_skip_blanks(buf, &p);
 306                 nr = simple_strtoul(p, &p, 0);
 307                 cmm_skip_blanks(p, &p);
 308                 seconds = simple_strtoul(p, &p, 0);
 309                 cmm_set_timeout(nr, seconds);
 310                 *ppos += *lenp;
 311         } else {
 312                 len = sprintf(buf, "%ld %ld\n",
 313                               cmm_timeout_pages, cmm_timeout_seconds);
 314                 if (len > *lenp)
 315                         len = *lenp;
 316                 if (copy_to_user(buffer, buf, len))
 317                         return -EFAULT;
 318                 *lenp = len;
 319                 *ppos += len;
 320         }
 321         return 0;
 322 }
 323
 324 static struct ctl_table cmm_table[] = {
 325         {
 326                 .procname       = "cmm_pages",
 327                 .mode           = 0644,
 328                 .proc_handler   = cmm_pages_handler,
 329         },
 330         {
 331                 .procname       = "cmm_timed_pages",
 332                 .mode           = 0644,
 333                 .proc_handler   = cmm_timed_pages_handler,
 334         },
 335         {
 336                 .procname       = "cmm_timeout",
 337                 .mode           = 0644,
 338                 .proc_handler   = cmm_timeout_handler,
 339         },
 340         { }
 341 };
 342
 343 static struct ctl_table cmm_dir_table[] = {
 344         {
 345                 .procname       = "vm",
 346                 .maxlen         = 0,
 347                 .mode           = 0555,
 348                 .child          = cmm_table,
 349         },
 350         { }
 351 };
 352
 353 #ifdef CONFIG_CMM_IUCV
 354 #define SMSG_PREFIX "CMM"
 355 static void cmm_smsg_target(const char *from, char *msg)
 356 {
 357         long nr, seconds;
 358
 359         if (strlen(sender) > 0 && strcmp(from, sender) != 0)
 360                 return;
 361         if (!cmm_skip_blanks(msg + strlen(SMSG_PREFIX), &msg))
 362                 return;
 363         if (strncmp(msg, "SHRINK", 6) == 0) {
 364                 if (!cmm_skip_blanks(msg + 6, &msg))
 365                         return;
 366                 nr = simple_strtoul(msg, &msg, 0);
 367                 cmm_skip_blanks(msg, &msg);
 368                 if (*msg == '\0')
 369                         cmm_set_pages(nr);
 370         } else if (strncmp(msg, "RELEASE", 7) == 0) {
 371                 if (!cmm_skip_blanks(msg + 7, &msg))
 372                         return;
 373                 nr = simple_strtoul(msg, &msg, 0);
 374                 cmm_skip_blanks(msg, &msg);
 375                 if (*msg == '\0')
 376                         cmm_add_timed_pages(nr);
 377         } else if (strncmp(msg, "REUSE", 5) == 0) {
 378                 if (!cmm_skip_blanks(msg + 5, &msg))
 379                         return;
 380                 nr = simple_strtoul(msg, &msg, 0);
 381                 if (!cmm_skip_blanks(msg, &msg))
 382                         return;
 383                 seconds = simple_strtoul(msg, &msg, 0);
 384                 cmm_skip_blanks(msg, &msg);
 385                 if (*msg == '\0')
 386                         cmm_set_timeout(nr, seconds);
 387         }
 388 }
 389 #endif
 390
 391 static struct ctl_table_header *cmm_sysctl_header;
 392
 393 static int cmm_suspend(void)
 394 {
 395         cmm_suspended = 1;
 396         cmm_free_pages(cmm_pages, &cmm_pages, &cmm_page_list);
 397         cmm_free_pages(cmm_timed_pages, &cmm_timed_pages, &cmm_timed_page_list);
 398         return 0;
 399 }
 400
 401 static int cmm_resume(void)
 402 {
 403         cmm_suspended = 0;
 404         cmm_kick_thread();
 405         return 0;
 406 }
 407
 408 static int cmm_power_event(struct notifier_block *this,
 409                            unsigned long event, void *ptr)
 410 {
 411         switch (event) {
 412         case PM_POST_HIBERNATION:
 413                 return cmm_resume();
 414         case PM_HIBERNATION_PREPARE:
 415                 return cmm_suspend();
 416         default:
 417                 return NOTIFY_DONE;
 418         }
 419 }
 420
 421 static struct notifier_block cmm_power_notifier = {
 422         .notifier_call = cmm_power_event,
 423 };
 424
 425 static int __init cmm_init(void)
 426 {
 427         int rc = -ENOMEM;
 428
 429         cmm_sysctl_header = register_sysctl_table(cmm_dir_table);
 430         if (!cmm_sysctl_header)
 431                 goto out_sysctl;
 432 #ifdef CONFIG_CMM_IUCV
 433         /* convert sender to uppercase characters */
 434         if (sender) {
 435                 int len = strlen(sender);
 436                 while (len--)
 437                         sender[len] = toupper(sender[len]);
 438         } else {
 439                 sender = cmm_default_sender;
 440         }
 441
 442         rc = smsg_register_callback(SMSG_PREFIX, cmm_smsg_target);
 443         if (rc < 0)
 444                 goto out_smsg;
 445 #endif
 446         rc = register_oom_notifier(&cmm_oom_nb);
 447         if (rc < 0)
 448                 goto out_oom_notify;
 449         rc = register_pm_notifier(&cmm_power_notifier);
 450         if (rc)
 451                 goto out_pm;
 452         cmm_thread_ptr = kthread_run(cmm_thread, NULL, "cmmthread");
 453         if (!IS_ERR(cmm_thread_ptr))
 454                 return 0;
 455
 456         rc = PTR_ERR(cmm_thread_ptr);
 457         unregister_pm_notifier(&cmm_power_notifier);
 458 out_pm:
 459         unregister_oom_notifier(&cmm_oom_nb);
 460 out_oom_notify:
 461 #ifdef CONFIG_CMM_IUCV
 462         smsg_unregister_callback(SMSG_PREFIX, cmm_smsg_target);
 463 out_smsg:
 464 #endif
 465         unregister_sysctl_table(cmm_sysctl_header);
 466 out_sysctl:
 467         del_timer_sync(&cmm_timer);
 468         return rc;
 469 }
 470 module_init(cmm_init);
 471
 472 static void __exit cmm_exit(void)
 473 {
 474         unregister_sysctl_table(cmm_sysctl_header);
 475 #ifdef CONFIG_CMM_IUCV
 476         smsg_unregister_callback(SMSG_PREFIX, cmm_smsg_target);
 477 #endif
 478         unregister_pm_notifier(&cmm_power_notifier);
 479         unregister_oom_notifier(&cmm_oom_nb);
 480         kthread_stop(cmm_thread_ptr);
 481         del_timer_sync(&cmm_timer);
 482         cmm_free_pages(cmm_pages, &cmm_pages, &cmm_page_list);
 483         cmm_free_pages(cmm_timed_pages, &cmm_timed_pages, &cmm_timed_page_list);
 484 }
 485 module_exit(cmm_exit);
 486
 487 MODULE_LICENSE("GPL");