1 /* 2 * Collaborative memory management interface. 3 * 4 * Copyright IBM Corp 2003, 2010 5 * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>, 6 * 7 */ 8 9 #include <linux/errno.h> 10 #include <linux/fs.h> 11 #include <linux/init.h> 12 #include <linux/module.h> 13 #include <linux/moduleparam.h> 14 #include <linux/gfp.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 #include <linux/suspend.h> 22 #include <linux/uaccess.h> 23 24 #include <asm/pgalloc.h> 25 #include <asm/diag.h> 26 27 #ifdef CONFIG_CMM_IUCV 28 static char *cmm_default_sender = "VMRMSVM"; 29 #endif 30 static char *sender; 31 module_param(sender, charp, 0400); 32 MODULE_PARM_DESC(sender, 33 "Guest name that may send SMSG messages (default VMRMSVM)"); 34 35 #include "../../../drivers/s390/net/smsgiucv.h" 36 37 #define CMM_NR_PAGES ((PAGE_SIZE / sizeof(unsigned long)) - 2) 38 39 struct cmm_page_array { 40 struct cmm_page_array *next; 41 unsigned long index; 42 unsigned long pages[CMM_NR_PAGES]; 43 }; 44 45 static long cmm_pages; 46 static long cmm_timed_pages; 47 static volatile long cmm_pages_target; 48 static volatile long cmm_timed_pages_target; 49 static long cmm_timeout_pages; 50 static long cmm_timeout_seconds; 51 static int cmm_suspended; 52 53 static struct cmm_page_array *cmm_page_list; 54 static struct cmm_page_array *cmm_timed_page_list; 55 static DEFINE_SPINLOCK(cmm_lock); 56 57 static struct task_struct *cmm_thread_ptr; 58 static DECLARE_WAIT_QUEUE_HEAD(cmm_thread_wait); 59 60 static void cmm_timer_fn(struct timer_list *); 61 static void cmm_set_timer(void); 62 static DEFINE_TIMER(cmm_timer, cmm_timer_fn); 63 64 static long cmm_alloc_pages(long nr, long *counter, 65 struct cmm_page_array **list) 66 { 67 struct cmm_page_array *pa, *npa; 68 unsigned long addr; 69 70 while (nr) { 71 addr = __get_free_page(GFP_NOIO); 72 if (!addr) 73 break; 74 spin_lock(&cmm_lock); 75 pa = *list; 76 if (!pa || pa->index >= CMM_NR_PAGES) { 77 /* Need a new page for the page list. */ 78 spin_unlock(&cmm_lock); 79 npa = (struct cmm_page_array *) 80 __get_free_page(GFP_NOIO); 81 if (!npa) { 82 free_page(addr); 83 break; 84 } 85 spin_lock(&cmm_lock); 86 pa = *list; 87 if (!pa || pa->index >= CMM_NR_PAGES) { 88 npa->next = pa; 89 npa->index = 0; 90 pa = npa; 91 *list = pa; 92 } else 93 free_page((unsigned long) npa); 94 } 95 diag10_range(addr >> PAGE_SHIFT, 1); 96 pa->pages[pa->index++] = addr; 97 (*counter)++; 98 spin_unlock(&cmm_lock); 99 nr--; 100 } 101 return nr; 102 } 103 104 static long cmm_free_pages(long nr, long *counter, struct cmm_page_array **list) 105 { 106 struct cmm_page_array *pa; 107 unsigned long addr; 108 109 spin_lock(&cmm_lock); 110 pa = *list; 111 while (nr) { 112 if (!pa || pa->index <= 0) 113 break; 114 addr = pa->pages[--pa->index]; 115 if (pa->index == 0) { 116 pa = pa->next; 117 free_page((unsigned long) *list); 118 *list = pa; 119 } 120 free_page(addr); 121 (*counter)--; 122 nr--; 123 } 124 spin_unlock(&cmm_lock); 125 return nr; 126 } 127 128 static int cmm_oom_notify(struct notifier_block *self, 129 unsigned long dummy, void *parm) 130 { 131 unsigned long *freed = parm; 132 long nr = 256; 133 134 nr = cmm_free_pages(nr, &cmm_timed_pages, &cmm_timed_page_list); 135 if (nr > 0) 136 nr = cmm_free_pages(nr, &cmm_pages, &cmm_page_list); 137 cmm_pages_target = cmm_pages; 138 cmm_timed_pages_target = cmm_timed_pages; 139 *freed += 256 - nr; 140 return NOTIFY_OK; 141 } 142 143 static struct notifier_block cmm_oom_nb = { 144 .notifier_call = cmm_oom_notify, 145 }; 146 147 static int cmm_thread(void *dummy) 148 { 149 int rc; 150 151 while (1) { 152 rc = wait_event_interruptible(cmm_thread_wait, 153 (!cmm_suspended && (cmm_pages != cmm_pages_target || 154 cmm_timed_pages != cmm_timed_pages_target)) || 155 kthread_should_stop()); 156 if (kthread_should_stop() || rc == -ERESTARTSYS) { 157 cmm_pages_target = cmm_pages; 158 cmm_timed_pages_target = cmm_timed_pages; 159 break; 160 } 161 if (cmm_pages_target > cmm_pages) { 162 if (cmm_alloc_pages(1, &cmm_pages, &cmm_page_list)) 163 cmm_pages_target = cmm_pages; 164 } else if (cmm_pages_target < cmm_pages) { 165 cmm_free_pages(1, &cmm_pages, &cmm_page_list); 166 } 167 if (cmm_timed_pages_target > cmm_timed_pages) { 168 if (cmm_alloc_pages(1, &cmm_timed_pages, 169 &cmm_timed_page_list)) 170 cmm_timed_pages_target = cmm_timed_pages; 171 } else if (cmm_timed_pages_target < cmm_timed_pages) { 172 cmm_free_pages(1, &cmm_timed_pages, 173 &cmm_timed_page_list); 174 } 175 if (cmm_timed_pages > 0 && !timer_pending(&cmm_timer)) 176 cmm_set_timer(); 177 } 178 return 0; 179 } 180 181 static void cmm_kick_thread(void) 182 { 183 wake_up(&cmm_thread_wait); 184 } 185 186 static void cmm_set_timer(void) 187 { 188 if (cmm_timed_pages_target <= 0 || cmm_timeout_seconds <= 0) { 189 if (timer_pending(&cmm_timer)) 190 del_timer(&cmm_timer); 191 return; 192 } 193 if (timer_pending(&cmm_timer)) { 194 if (mod_timer(&cmm_timer, jiffies + cmm_timeout_seconds*HZ)) 195 return; 196 } 197 cmm_timer.expires = jiffies + cmm_timeout_seconds*HZ; 198 add_timer(&cmm_timer); 199 } 200 201 static void cmm_timer_fn(struct timer_list *unused) 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 static void cmm_set_pages(long nr) 215 { 216 cmm_pages_target = nr; 217 cmm_kick_thread(); 218 } 219 220 static long cmm_get_pages(void) 221 { 222 return cmm_pages; 223 } 224 225 static void cmm_add_timed_pages(long nr) 226 { 227 cmm_timed_pages_target += nr; 228 cmm_kick_thread(); 229 } 230 231 static long cmm_get_timed_pages(void) 232 { 233 return cmm_timed_pages; 234 } 235 236 static void cmm_set_timeout(long nr, long seconds) 237 { 238 cmm_timeout_pages = nr; 239 cmm_timeout_seconds = seconds; 240 cmm_set_timer(); 241 } 242 243 static int cmm_skip_blanks(char *cp, char **endp) 244 { 245 char *str; 246 247 for (str = cp; *str == ' ' || *str == '\t'; str++) 248 ; 249 *endp = str; 250 return str != cp; 251 } 252 253 static struct ctl_table cmm_table[]; 254 255 static int cmm_pages_handler(struct ctl_table *ctl, int write, 256 void __user *buffer, size_t *lenp, loff_t *ppos) 257 { 258 char buf[16], *p; 259 unsigned int len; 260 long nr; 261 262 if (!*lenp || (*ppos && !write)) { 263 *lenp = 0; 264 return 0; 265 } 266 267 if (write) { 268 len = *lenp; 269 if (copy_from_user(buf, buffer, 270 len > sizeof(buf) ? sizeof(buf) : len)) 271 return -EFAULT; 272 buf[sizeof(buf) - 1] = '\0'; 273 cmm_skip_blanks(buf, &p); 274 nr = simple_strtoul(p, &p, 0); 275 if (ctl == &cmm_table[0]) 276 cmm_set_pages(nr); 277 else 278 cmm_add_timed_pages(nr); 279 } else { 280 if (ctl == &cmm_table[0]) 281 nr = cmm_get_pages(); 282 else 283 nr = cmm_get_timed_pages(); 284 len = sprintf(buf, "%ld\n", nr); 285 if (len > *lenp) 286 len = *lenp; 287 if (copy_to_user(buffer, buf, len)) 288 return -EFAULT; 289 } 290 *lenp = len; 291 *ppos += len; 292 return 0; 293 } 294 295 static int cmm_timeout_handler(struct ctl_table *ctl, int write, 296 void __user *buffer, size_t *lenp, loff_t *ppos) 297 { 298 char buf[64], *p; 299 long nr, seconds; 300 unsigned int len; 301 302 if (!*lenp || (*ppos && !write)) { 303 *lenp = 0; 304 return 0; 305 } 306 307 if (write) { 308 len = *lenp; 309 if (copy_from_user(buf, buffer, 310 len > sizeof(buf) ? sizeof(buf) : len)) 311 return -EFAULT; 312 buf[sizeof(buf) - 1] = '\0'; 313 cmm_skip_blanks(buf, &p); 314 nr = simple_strtoul(p, &p, 0); 315 cmm_skip_blanks(p, &p); 316 seconds = simple_strtoul(p, &p, 0); 317 cmm_set_timeout(nr, seconds); 318 } else { 319 len = sprintf(buf, "%ld %ld\n", 320 cmm_timeout_pages, cmm_timeout_seconds); 321 if (len > *lenp) 322 len = *lenp; 323 if (copy_to_user(buffer, buf, len)) 324 return -EFAULT; 325 } 326 *lenp = len; 327 *ppos += len; 328 return 0; 329 } 330 331 static struct ctl_table cmm_table[] = { 332 { 333 .procname = "cmm_pages", 334 .mode = 0644, 335 .proc_handler = cmm_pages_handler, 336 }, 337 { 338 .procname = "cmm_timed_pages", 339 .mode = 0644, 340 .proc_handler = cmm_pages_handler, 341 }, 342 { 343 .procname = "cmm_timeout", 344 .mode = 0644, 345 .proc_handler = cmm_timeout_handler, 346 }, 347 { } 348 }; 349 350 static struct ctl_table cmm_dir_table[] = { 351 { 352 .procname = "vm", 353 .maxlen = 0, 354 .mode = 0555, 355 .child = cmm_table, 356 }, 357 { } 358 }; 359 360 #ifdef CONFIG_CMM_IUCV 361 #define SMSG_PREFIX "CMM" 362 static void cmm_smsg_target(const char *from, char *msg) 363 { 364 long nr, seconds; 365 366 if (strlen(sender) > 0 && strcmp(from, sender) != 0) 367 return; 368 if (!cmm_skip_blanks(msg + strlen(SMSG_PREFIX), &msg)) 369 return; 370 if (strncmp(msg, "SHRINK", 6) == 0) { 371 if (!cmm_skip_blanks(msg + 6, &msg)) 372 return; 373 nr = simple_strtoul(msg, &msg, 0); 374 cmm_skip_blanks(msg, &msg); 375 if (*msg == '\0') 376 cmm_set_pages(nr); 377 } else if (strncmp(msg, "RELEASE", 7) == 0) { 378 if (!cmm_skip_blanks(msg + 7, &msg)) 379 return; 380 nr = simple_strtoul(msg, &msg, 0); 381 cmm_skip_blanks(msg, &msg); 382 if (*msg == '\0') 383 cmm_add_timed_pages(nr); 384 } else if (strncmp(msg, "REUSE", 5) == 0) { 385 if (!cmm_skip_blanks(msg + 5, &msg)) 386 return; 387 nr = simple_strtoul(msg, &msg, 0); 388 if (!cmm_skip_blanks(msg, &msg)) 389 return; 390 seconds = simple_strtoul(msg, &msg, 0); 391 cmm_skip_blanks(msg, &msg); 392 if (*msg == '\0') 393 cmm_set_timeout(nr, seconds); 394 } 395 } 396 #endif 397 398 static struct ctl_table_header *cmm_sysctl_header; 399 400 static int cmm_suspend(void) 401 { 402 cmm_suspended = 1; 403 cmm_free_pages(cmm_pages, &cmm_pages, &cmm_page_list); 404 cmm_free_pages(cmm_timed_pages, &cmm_timed_pages, &cmm_timed_page_list); 405 return 0; 406 } 407 408 static int cmm_resume(void) 409 { 410 cmm_suspended = 0; 411 cmm_kick_thread(); 412 return 0; 413 } 414 415 static int cmm_power_event(struct notifier_block *this, 416 unsigned long event, void *ptr) 417 { 418 switch (event) { 419 case PM_POST_HIBERNATION: 420 return cmm_resume(); 421 case PM_HIBERNATION_PREPARE: 422 return cmm_suspend(); 423 default: 424 return NOTIFY_DONE; 425 } 426 } 427 428 static struct notifier_block cmm_power_notifier = { 429 .notifier_call = cmm_power_event, 430 }; 431 432 static int __init cmm_init(void) 433 { 434 int rc = -ENOMEM; 435 436 cmm_sysctl_header = register_sysctl_table(cmm_dir_table); 437 if (!cmm_sysctl_header) 438 goto out_sysctl; 439 #ifdef CONFIG_CMM_IUCV 440 /* convert sender to uppercase characters */ 441 if (sender) { 442 int len = strlen(sender); 443 while (len--) 444 sender[len] = toupper(sender[len]); 445 } else { 446 sender = cmm_default_sender; 447 } 448 449 rc = smsg_register_callback(SMSG_PREFIX, cmm_smsg_target); 450 if (rc < 0) 451 goto out_smsg; 452 #endif 453 rc = register_oom_notifier(&cmm_oom_nb); 454 if (rc < 0) 455 goto out_oom_notify; 456 rc = register_pm_notifier(&cmm_power_notifier); 457 if (rc) 458 goto out_pm; 459 cmm_thread_ptr = kthread_run(cmm_thread, NULL, "cmmthread"); 460 if (!IS_ERR(cmm_thread_ptr)) 461 return 0; 462 463 rc = PTR_ERR(cmm_thread_ptr); 464 unregister_pm_notifier(&cmm_power_notifier); 465 out_pm: 466 unregister_oom_notifier(&cmm_oom_nb); 467 out_oom_notify: 468 #ifdef CONFIG_CMM_IUCV 469 smsg_unregister_callback(SMSG_PREFIX, cmm_smsg_target); 470 out_smsg: 471 #endif 472 unregister_sysctl_table(cmm_sysctl_header); 473 out_sysctl: 474 del_timer_sync(&cmm_timer); 475 return rc; 476 } 477 module_init(cmm_init); 478 479 static void __exit cmm_exit(void) 480 { 481 unregister_sysctl_table(cmm_sysctl_header); 482 #ifdef CONFIG_CMM_IUCV 483 smsg_unregister_callback(SMSG_PREFIX, cmm_smsg_target); 484 #endif 485 unregister_pm_notifier(&cmm_power_notifier); 486 unregister_oom_notifier(&cmm_oom_nb); 487 kthread_stop(cmm_thread_ptr); 488 del_timer_sync(&cmm_timer); 489 cmm_free_pages(cmm_pages, &cmm_pages, &cmm_page_list); 490 cmm_free_pages(cmm_timed_pages, &cmm_timed_pages, &cmm_timed_page_list); 491 } 492 module_exit(cmm_exit); 493 494 MODULE_LICENSE("GPL"); 495