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
  19 #include <asm/pgalloc.h>
  20 #include <asm/uaccess.h>
  21
  22 static char *sender = "VMRMSVM";
  23 module_param(sender, charp, 0400);
  24 MODULE_PARM_DESC(sender,
  25                  "Guest name that may send SMSG messages (default VMRMSVM)");
  26
  27 #include "../../../drivers/s390/net/smsgiucv.h"
  28
  29 #define CMM_NR_PAGES ((PAGE_SIZE / sizeof(unsigned long)) - 2)
  30
  31 struct cmm_page_array {
  32         struct cmm_page_array *next;
  33         unsigned long index;
  34         unsigned long pages[CMM_NR_PAGES];
  35 };
  36
  37 static long cmm_pages = 0;
  38 static long cmm_timed_pages = 0;
  39 static volatile long cmm_pages_target = 0;
  40 static volatile long cmm_timed_pages_target = 0;
  41 static long cmm_timeout_pages = 0;
  42 static long cmm_timeout_seconds = 0;
  43
  44 static struct cmm_page_array *cmm_page_list = NULL;
  45 static struct cmm_page_array *cmm_timed_page_list = NULL;
  46
  47 static unsigned long cmm_thread_active = 0;
  48 static struct work_struct cmm_thread_starter;
  49 static wait_queue_head_t cmm_thread_wait;
  50 static struct timer_list cmm_timer;
  51
  52 static void cmm_timer_fn(unsigned long);
  53 static void cmm_set_timer(void);
  54
  55 static long
  56 cmm_alloc_pages(long pages, long *counter, struct cmm_page_array **list)
  57 {
  58         struct cmm_page_array *pa;
  59         unsigned long page;
  60
  61         pa = *list;
  62         while (pages) {
  63                 page = __get_free_page(GFP_NOIO);
  64                 if (!page)
  65                         break;
  66                 if (!pa || pa->index >= CMM_NR_PAGES) {
  67                         /* Need a new page for the page list. */
  68                         pa = (struct cmm_page_array *)
  69                                 __get_free_page(GFP_NOIO);
  70                         if (!pa) {
  71                                 free_page(page);
  72                                 break;
  73                         }
  74                         pa->next = *list;
  75                         pa->index = 0;
  76                         *list = pa;
  77                 }
  78                 diag10(page);
  79                 pa->pages[pa->index++] = page;
  80                 (*counter)++;
  81                 pages--;
  82         }
  83         return pages;
  84 }
  85
  86 static void
  87 cmm_free_pages(long pages, long *counter, struct cmm_page_array **list)
  88 {
  89         struct cmm_page_array *pa;
  90         unsigned long page;
  91
  92         pa = *list;
  93         while (pages) {
  94                 if (!pa || pa->index <= 0)
  95                         break;
  96                 page = pa->pages[--pa->index];
  97                 if (pa->index == 0) {
  98                         pa = pa->next;
  99                         free_page((unsigned long) *list);
 100                         *list = pa;
 101                 }
 102                 free_page(page);
 103                 (*counter)--;
 104                 pages--;
 105         }
 106 }
 107
 108 static int
 109 cmm_thread(void *dummy)
 110 {
 111         int rc;
 112
 113         daemonize("cmmthread");
 114         while (1) {
 115                 rc = wait_event_interruptible(cmm_thread_wait,
 116                         (cmm_pages != cmm_pages_target ||
 117                          cmm_timed_pages != cmm_timed_pages_target));
 118                 if (rc == -ERESTARTSYS) {
 119                         /* Got kill signal. End thread. */
 120                         clear_bit(0, &cmm_thread_active);
 121                         cmm_pages_target = cmm_pages;
 122                         cmm_timed_pages_target = cmm_timed_pages;
 123                         break;
 124                 }
 125                 if (cmm_pages_target > cmm_pages) {
 126                         if (cmm_alloc_pages(1, &cmm_pages, &cmm_page_list))
 127                                 cmm_pages_target = cmm_pages;
 128                 } else if (cmm_pages_target < cmm_pages) {
 129                         cmm_free_pages(1, &cmm_pages, &cmm_page_list);
 130                 }
 131                 if (cmm_timed_pages_target > cmm_timed_pages) {
 132                         if (cmm_alloc_pages(1, &cmm_timed_pages,
 133                                            &cmm_timed_page_list))
 134                                 cmm_timed_pages_target = cmm_timed_pages;
 135                 } else if (cmm_timed_pages_target < cmm_timed_pages) {
 136                         cmm_free_pages(1, &cmm_timed_pages,
 137                                        &cmm_timed_page_list);
 138                 }
 139                 if (cmm_timed_pages > 0 && !timer_pending(&cmm_timer))
 140                         cmm_set_timer();
 141         }
 142         return 0;
 143 }
 144
 145 static void
 146 cmm_start_thread(void)
 147 {
 148         kernel_thread(cmm_thread, NULL, 0);
 149 }
 150
 151 static void
 152 cmm_kick_thread(void)
 153 {
 154         if (!test_and_set_bit(0, &cmm_thread_active))
 155                 schedule_work(&cmm_thread_starter);
 156         wake_up(&cmm_thread_wait);
 157 }
 158
 159 static void
 160 cmm_set_timer(void)
 161 {
 162         if (cmm_timed_pages_target <= 0 || cmm_timeout_seconds <= 0) {
 163                 if (timer_pending(&cmm_timer))
 164                         del_timer(&cmm_timer);
 165                 return;
 166         }
 167         if (timer_pending(&cmm_timer)) {
 168                 if (mod_timer(&cmm_timer, jiffies + cmm_timeout_seconds*HZ))
 169                         return;
 170         }
 171         cmm_timer.function = cmm_timer_fn;
 172         cmm_timer.data = 0;
 173         cmm_timer.expires = jiffies + cmm_timeout_seconds*HZ;
 174         add_timer(&cmm_timer);
 175 }
 176
 177 static void
 178 cmm_timer_fn(unsigned long ignored)
 179 {
 180         long pages;
 181
 182         pages = cmm_timed_pages_target - cmm_timeout_pages;
 183         if (pages < 0)
 184                 cmm_timed_pages_target = 0;
 185         else
 186                 cmm_timed_pages_target = pages;
 187         cmm_kick_thread();
 188         cmm_set_timer();
 189 }
 190
 191 void
 192 cmm_set_pages(long pages)
 193 {
 194         cmm_pages_target = pages;
 195         cmm_kick_thread();
 196 }
 197
 198 long
 199 cmm_get_pages(void)
 200 {
 201         return cmm_pages;
 202 }
 203
 204 void
 205 cmm_add_timed_pages(long pages)
 206 {
 207         cmm_timed_pages_target += pages;
 208         cmm_kick_thread();
 209 }
 210
 211 long
 212 cmm_get_timed_pages(void)
 213 {
 214         return cmm_timed_pages;
 215 }
 216
 217 void
 218 cmm_set_timeout(long pages, long seconds)
 219 {
 220         cmm_timeout_pages = pages;
 221         cmm_timeout_seconds = seconds;
 222         cmm_set_timer();
 223 }
 224
 225 static inline int
 226 cmm_skip_blanks(char *cp, char **endp)
 227 {
 228         char *str;
 229
 230         for (str = cp; *str == ' ' || *str == '\t'; str++);
 231         *endp = str;
 232         return str != cp;
 233 }
 234
 235 #ifdef CONFIG_CMM_PROC
 236 /* These will someday get removed. */
 237 #define VM_CMM_PAGES            1111
 238 #define VM_CMM_TIMED_PAGES      1112
 239 #define VM_CMM_TIMEOUT          1113
 240
 241 static struct ctl_table cmm_table[];
 242
 243 static int
 244 cmm_pages_handler(ctl_table *ctl, int write, struct file *filp,
 245                   void __user *buffer, size_t *lenp, loff_t *ppos)
 246 {
 247         char buf[16], *p;
 248         long pages;
 249         int len;
 250
 251         if (!*lenp || (*ppos && !write)) {
 252                 *lenp = 0;
 253                 return 0;
 254         }
 255
 256         if (write) {
 257                 len = *lenp;
 258                 if (copy_from_user(buf, buffer,
 259                                    len > sizeof(buf) ? sizeof(buf) : len))
 260                         return -EFAULT;
 261                 buf[sizeof(buf) - 1] = '\0';
 262                 cmm_skip_blanks(buf, &p);
 263                 pages = simple_strtoul(p, &p, 0);
 264                 if (ctl == &cmm_table[0])
 265                         cmm_set_pages(pages);
 266                 else
 267                         cmm_add_timed_pages(pages);
 268         } else {
 269                 if (ctl == &cmm_table[0])
 270                         pages = cmm_get_pages();
 271                 else
 272                         pages = cmm_get_timed_pages();
 273                 len = sprintf(buf, "%ld\n", pages);
 274                 if (len > *lenp)
 275                         len = *lenp;
 276                 if (copy_to_user(buffer, buf, len))
 277                         return -EFAULT;
 278         }
 279         *lenp = len;
 280         *ppos += len;
 281         return 0;
 282 }
 283
 284 static int
 285 cmm_timeout_handler(ctl_table *ctl, int write, struct file *filp,
 286                     void __user *buffer, size_t *lenp, loff_t *ppos)
 287 {
 288         char buf[64], *p;
 289         long pages, seconds;
 290         int len;
 291
 292         if (!*lenp || (*ppos && !write)) {
 293                 *lenp = 0;
 294                 return 0;
 295         }
 296
 297         if (write) {
 298                 len = *lenp;
 299                 if (copy_from_user(buf, buffer,
 300                                    len > sizeof(buf) ? sizeof(buf) : len))
 301                         return -EFAULT;
 302                 buf[sizeof(buf) - 1] = '\0';
 303                 cmm_skip_blanks(buf, &p);
 304                 pages = simple_strtoul(p, &p, 0);
 305                 cmm_skip_blanks(p, &p);
 306                 seconds = simple_strtoul(p, &p, 0);
 307                 cmm_set_timeout(pages, seconds);
 308         } else {
 309                 len = sprintf(buf, "%ld %ld\n",
 310                               cmm_timeout_pages, cmm_timeout_seconds);
 311                 if (len > *lenp)
 312                         len = *lenp;
 313                 if (copy_to_user(buffer, buf, len))
 314                         return -EFAULT;
 315         }
 316         *lenp = len;
 317         *ppos += len;
 318         return 0;
 319 }
 320
 321 static struct ctl_table cmm_table[] = {
 322         {
 323                 .ctl_name       = VM_CMM_PAGES,
 324                 .procname       = "cmm_pages",
 325                 .mode           = 0644,
 326                 .proc_handler   = &cmm_pages_handler,
 327         },
 328         {
 329                 .ctl_name       = VM_CMM_TIMED_PAGES,
 330                 .procname       = "cmm_timed_pages",
 331                 .mode           = 0644,
 332                 .proc_handler   = &cmm_pages_handler,
 333         },
 334         {
 335                 .ctl_name       = VM_CMM_TIMEOUT,
 336                 .procname       = "cmm_timeout",
 337                 .mode           = 0644,
 338                 .proc_handler   = &cmm_timeout_handler,
 339         },
 340         { .ctl_name = 0 }
 341 };
 342
 343 static struct ctl_table cmm_dir_table[] = {
 344         {
 345                 .ctl_name       = CTL_VM,
 346                 .procname       = "vm",
 347                 .maxlen         = 0,
 348                 .mode           = 0555,
 349                 .child          = cmm_table,
 350         },
 351         { .ctl_name = 0 }
 352 };
 353 #endif
 354
 355 #ifdef CONFIG_CMM_IUCV
 356 #define SMSG_PREFIX "CMM"
 357 static void
 358 cmm_smsg_target(char *from, char *msg)
 359 {
 360         long pages, seconds;
 361
 362         if (strlen(sender) > 0 && strcmp(from, sender) != 0)
 363                 return;
 364         if (!cmm_skip_blanks(msg + strlen(SMSG_PREFIX), &msg))
 365                 return;
 366         if (strncmp(msg, "SHRINK", 6) == 0) {
 367                 if (!cmm_skip_blanks(msg + 6, &msg))
 368                         return;
 369                 pages = simple_strtoul(msg, &msg, 0);
 370                 cmm_skip_blanks(msg, &msg);
 371                 if (*msg == '\0')
 372                         cmm_set_pages(pages);
 373         } else if (strncmp(msg, "RELEASE", 7) == 0) {
 374                 if (!cmm_skip_blanks(msg + 7, &msg))
 375                         return;
 376                 pages = simple_strtoul(msg, &msg, 0);
 377                 cmm_skip_blanks(msg, &msg);
 378                 if (*msg == '\0')
 379                         cmm_add_timed_pages(pages);
 380         } else if (strncmp(msg, "REUSE", 5) == 0) {
 381                 if (!cmm_skip_blanks(msg + 5, &msg))
 382                         return;
 383                 pages = simple_strtoul(msg, &msg, 0);
 384                 if (!cmm_skip_blanks(msg, &msg))
 385                         return;
 386                 seconds = simple_strtoul(msg, &msg, 0);
 387                 cmm_skip_blanks(msg, &msg);
 388                 if (*msg == '\0')
 389                         cmm_set_timeout(pages, seconds);
 390         }
 391 }
 392 #endif
 393
 394 struct ctl_table_header *cmm_sysctl_header;
 395
 396 static int
 397 cmm_init (void)
 398 {
 399 #ifdef CONFIG_CMM_PROC
 400         cmm_sysctl_header = register_sysctl_table(cmm_dir_table, 1);
 401 #endif
 402 #ifdef CONFIG_CMM_IUCV
 403         smsg_register_callback(SMSG_PREFIX, cmm_smsg_target);
 404 #endif
 405         INIT_WORK(&cmm_thread_starter, (void *) cmm_start_thread, NULL);
 406         init_waitqueue_head(&cmm_thread_wait);
 407         init_timer(&cmm_timer);
 408         return 0;
 409 }
 410
 411 static void
 412 cmm_exit(void)
 413 {
 414         cmm_free_pages(cmm_pages, &cmm_pages, &cmm_page_list);
 415         cmm_free_pages(cmm_timed_pages, &cmm_timed_pages, &cmm_timed_page_list);
 416 #ifdef CONFIG_CMM_PROC
 417         unregister_sysctl_table(cmm_sysctl_header);
 418 #endif
 419 #ifdef CONFIG_CMM_IUCV
 420         smsg_unregister_callback(SMSG_PREFIX, cmm_smsg_target);
 421 #endif
 422 }
 423
 424 module_init(cmm_init);
 425 module_exit(cmm_exit);
 426
 427 EXPORT_SYMBOL(cmm_set_pages);
 428 EXPORT_SYMBOL(cmm_get_pages);
 429 EXPORT_SYMBOL(cmm_add_timed_pages);
 430 EXPORT_SYMBOL(cmm_get_timed_pages);
 431 EXPORT_SYMBOL(cmm_set_timeout);
 432
 433 MODULE_LICENSE("GPL");