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/string_helpers.h> 18 #include <linux/sysctl.h> 19 #include <linux/swap.h> 20 #include <linux/kthread.h> 21 #include <linux/oom.h> 22 #include <linux/uaccess.h> 23 24 #include <asm/diag.h> 25 26 #ifdef CONFIG_CMM_IUCV 27 static char *cmm_default_sender = "VMRMSVM"; 28 #endif 29 static char *sender; 30 module_param(sender, charp, 0400); 31 MODULE_PARM_DESC(sender, 32 "Guest name that may send SMSG messages (default VMRMSVM)"); 33 34 #include "../../../drivers/s390/net/smsgiucv.h" 35 36 #define CMM_NR_PAGES ((PAGE_SIZE / sizeof(unsigned long)) - 2) 37 38 struct cmm_page_array { 39 struct cmm_page_array *next; 40 unsigned long index; 41 unsigned long pages[CMM_NR_PAGES]; 42 }; 43 44 static long cmm_pages; 45 static long cmm_timed_pages; 46 static volatile long cmm_pages_target; 47 static volatile long cmm_timed_pages_target; 48 static long cmm_timeout_pages; 49 static long cmm_timeout_seconds; 50 51 static struct cmm_page_array *cmm_page_list; 52 static struct cmm_page_array *cmm_timed_page_list; 53 static DEFINE_SPINLOCK(cmm_lock); 54 55 static struct task_struct *cmm_thread_ptr; 56 static DECLARE_WAIT_QUEUE_HEAD(cmm_thread_wait); 57 58 static void cmm_timer_fn(struct timer_list *); 59 static void cmm_set_timer(void); 60 static DEFINE_TIMER(cmm_timer, cmm_timer_fn); 61 62 static long cmm_alloc_pages(long nr, long *counter, 63 struct cmm_page_array **list) 64 { 65 struct cmm_page_array *pa, *npa; 66 unsigned long addr; 67 68 while (nr) { 69 addr = __get_free_page(GFP_NOIO); 70 if (!addr) 71 break; 72 spin_lock(&cmm_lock); 73 pa = *list; 74 if (!pa || pa->index >= CMM_NR_PAGES) { 75 /* Need a new page for the page list. */ 76 spin_unlock(&cmm_lock); 77 npa = (struct cmm_page_array *) 78 __get_free_page(GFP_NOIO); 79 if (!npa) { 80 free_page(addr); 81 break; 82 } 83 spin_lock(&cmm_lock); 84 pa = *list; 85 if (!pa || pa->index >= CMM_NR_PAGES) { 86 npa->next = pa; 87 npa->index = 0; 88 pa = npa; 89 *list = pa; 90 } else 91 free_page((unsigned long) npa); 92 } 93 diag10_range(virt_to_pfn((void *)addr), 1); 94 pa->pages[pa->index++] = addr; 95 (*counter)++; 96 spin_unlock(&cmm_lock); 97 nr--; 98 } 99 return nr; 100 } 101 102 static long cmm_free_pages(long nr, long *counter, struct cmm_page_array **list) 103 { 104 struct cmm_page_array *pa; 105 unsigned long addr; 106 107 spin_lock(&cmm_lock); 108 pa = *list; 109 while (nr) { 110 if (!pa || pa->index <= 0) 111 break; 112 addr = pa->pages[--pa->index]; 113 if (pa->index == 0) { 114 pa = pa->next; 115 free_page((unsigned long) *list); 116 *list = pa; 117 } 118 free_page(addr); 119 (*counter)--; 120 nr--; 121 } 122 spin_unlock(&cmm_lock); 123 return nr; 124 } 125 126 static int cmm_oom_notify(struct notifier_block *self, 127 unsigned long dummy, void *parm) 128 { 129 unsigned long *freed = parm; 130 long nr = 256; 131 132 nr = cmm_free_pages(nr, &cmm_timed_pages, &cmm_timed_page_list); 133 if (nr > 0) 134 nr = cmm_free_pages(nr, &cmm_pages, &cmm_page_list); 135 cmm_pages_target = cmm_pages; 136 cmm_timed_pages_target = cmm_timed_pages; 137 *freed += 256 - nr; 138 return NOTIFY_OK; 139 } 140 141 static struct notifier_block cmm_oom_nb = { 142 .notifier_call = cmm_oom_notify, 143 }; 144 145 static int cmm_thread(void *dummy) 146 { 147 int rc; 148 149 while (1) { 150 rc = wait_event_interruptible(cmm_thread_wait, 151 cmm_pages != cmm_pages_target || 152 cmm_timed_pages != cmm_timed_pages_target || 153 kthread_should_stop()); 154 if (kthread_should_stop() || rc == -ERESTARTSYS) { 155 cmm_pages_target = cmm_pages; 156 cmm_timed_pages_target = cmm_timed_pages; 157 break; 158 } 159 if (cmm_pages_target > cmm_pages) { 160 if (cmm_alloc_pages(1, &cmm_pages, &cmm_page_list)) 161 cmm_pages_target = cmm_pages; 162 } else if (cmm_pages_target < cmm_pages) { 163 cmm_free_pages(1, &cmm_pages, &cmm_page_list); 164 } 165 if (cmm_timed_pages_target > cmm_timed_pages) { 166 if (cmm_alloc_pages(1, &cmm_timed_pages, 167 &cmm_timed_page_list)) 168 cmm_timed_pages_target = cmm_timed_pages; 169 } else if (cmm_timed_pages_target < cmm_timed_pages) { 170 cmm_free_pages(1, &cmm_timed_pages, 171 &cmm_timed_page_list); 172 } 173 if (cmm_timed_pages > 0 && !timer_pending(&cmm_timer)) 174 cmm_set_timer(); 175 } 176 return 0; 177 } 178 179 static void cmm_kick_thread(void) 180 { 181 wake_up(&cmm_thread_wait); 182 } 183 184 static void cmm_set_timer(void) 185 { 186 if (cmm_timed_pages_target <= 0 || cmm_timeout_seconds <= 0) { 187 if (timer_pending(&cmm_timer)) 188 del_timer(&cmm_timer); 189 return; 190 } 191 mod_timer(&cmm_timer, jiffies + msecs_to_jiffies(cmm_timeout_seconds * MSEC_PER_SEC)); 192 } 193 194 static void cmm_timer_fn(struct timer_list *unused) 195 { 196 long nr; 197 198 nr = cmm_timed_pages_target - cmm_timeout_pages; 199 if (nr < 0) 200 cmm_timed_pages_target = 0; 201 else 202 cmm_timed_pages_target = nr; 203 cmm_kick_thread(); 204 cmm_set_timer(); 205 } 206 207 static void cmm_set_pages(long nr) 208 { 209 cmm_pages_target = nr; 210 cmm_kick_thread(); 211 } 212 213 static long cmm_get_pages(void) 214 { 215 return cmm_pages; 216 } 217 218 static void cmm_add_timed_pages(long nr) 219 { 220 cmm_timed_pages_target += nr; 221 cmm_kick_thread(); 222 } 223 224 static long cmm_get_timed_pages(void) 225 { 226 return cmm_timed_pages; 227 } 228 229 static void cmm_set_timeout(long nr, long seconds) 230 { 231 cmm_timeout_pages = nr; 232 cmm_timeout_seconds = seconds; 233 cmm_set_timer(); 234 } 235 236 static int cmm_skip_blanks(char *cp, char **endp) 237 { 238 char *str; 239 240 for (str = cp; *str == ' ' || *str == '\t'; str++) 241 ; 242 *endp = str; 243 return str != cp; 244 } 245 246 static int cmm_pages_handler(struct ctl_table *ctl, int write, 247 void *buffer, size_t *lenp, loff_t *ppos) 248 { 249 long nr = cmm_get_pages(); 250 struct ctl_table ctl_entry = { 251 .procname = ctl->procname, 252 .data = &nr, 253 .maxlen = sizeof(long), 254 }; 255 int rc; 256 257 rc = proc_doulongvec_minmax(&ctl_entry, write, buffer, lenp, ppos); 258 if (rc < 0 || !write) 259 return rc; 260 261 cmm_set_pages(nr); 262 return 0; 263 } 264 265 static int cmm_timed_pages_handler(struct ctl_table *ctl, int write, 266 void *buffer, size_t *lenp, 267 loff_t *ppos) 268 { 269 long nr = cmm_get_timed_pages(); 270 struct ctl_table ctl_entry = { 271 .procname = ctl->procname, 272 .data = &nr, 273 .maxlen = sizeof(long), 274 }; 275 int rc; 276 277 rc = proc_doulongvec_minmax(&ctl_entry, write, buffer, lenp, ppos); 278 if (rc < 0 || !write) 279 return rc; 280 281 cmm_add_timed_pages(nr); 282 return 0; 283 } 284 285 static int cmm_timeout_handler(struct ctl_table *ctl, int write, 286 void *buffer, size_t *lenp, loff_t *ppos) 287 { 288 char buf[64], *p; 289 long nr, seconds; 290 unsigned int len; 291 292 if (!*lenp || (*ppos && !write)) { 293 *lenp = 0; 294 return 0; 295 } 296 297 if (write) { 298 len = min(*lenp, sizeof(buf)); 299 memcpy(buf, buffer, len); 300 buf[len - 1] = '\0'; 301 cmm_skip_blanks(buf, &p); 302 nr = simple_strtoul(p, &p, 0); 303 cmm_skip_blanks(p, &p); 304 seconds = simple_strtoul(p, &p, 0); 305 cmm_set_timeout(nr, seconds); 306 *ppos += *lenp; 307 } else { 308 len = sprintf(buf, "%ld %ld\n", 309 cmm_timeout_pages, cmm_timeout_seconds); 310 if (len > *lenp) 311 len = *lenp; 312 memcpy(buffer, buf, len); 313 *lenp = len; 314 *ppos += len; 315 } 316 return 0; 317 } 318 319 static struct ctl_table cmm_table[] = { 320 { 321 .procname = "cmm_pages", 322 .mode = 0644, 323 .proc_handler = cmm_pages_handler, 324 }, 325 { 326 .procname = "cmm_timed_pages", 327 .mode = 0644, 328 .proc_handler = cmm_timed_pages_handler, 329 }, 330 { 331 .procname = "cmm_timeout", 332 .mode = 0644, 333 .proc_handler = cmm_timeout_handler, 334 }, 335 { } 336 }; 337 338 #ifdef CONFIG_CMM_IUCV 339 #define SMSG_PREFIX "CMM" 340 static void cmm_smsg_target(const char *from, char *msg) 341 { 342 long nr, seconds; 343 344 if (strlen(sender) > 0 && strcmp(from, sender) != 0) 345 return; 346 if (!cmm_skip_blanks(msg + strlen(SMSG_PREFIX), &msg)) 347 return; 348 if (strncmp(msg, "SHRINK", 6) == 0) { 349 if (!cmm_skip_blanks(msg + 6, &msg)) 350 return; 351 nr = simple_strtoul(msg, &msg, 0); 352 cmm_skip_blanks(msg, &msg); 353 if (*msg == '\0') 354 cmm_set_pages(nr); 355 } else if (strncmp(msg, "RELEASE", 7) == 0) { 356 if (!cmm_skip_blanks(msg + 7, &msg)) 357 return; 358 nr = simple_strtoul(msg, &msg, 0); 359 cmm_skip_blanks(msg, &msg); 360 if (*msg == '\0') 361 cmm_add_timed_pages(nr); 362 } else if (strncmp(msg, "REUSE", 5) == 0) { 363 if (!cmm_skip_blanks(msg + 5, &msg)) 364 return; 365 nr = simple_strtoul(msg, &msg, 0); 366 if (!cmm_skip_blanks(msg, &msg)) 367 return; 368 seconds = simple_strtoul(msg, &msg, 0); 369 cmm_skip_blanks(msg, &msg); 370 if (*msg == '\0') 371 cmm_set_timeout(nr, seconds); 372 } 373 } 374 #endif 375 376 static struct ctl_table_header *cmm_sysctl_header; 377 378 static int __init cmm_init(void) 379 { 380 int rc = -ENOMEM; 381 382 cmm_sysctl_header = register_sysctl("vm", cmm_table); 383 if (!cmm_sysctl_header) 384 goto out_sysctl; 385 #ifdef CONFIG_CMM_IUCV 386 /* convert sender to uppercase characters */ 387 if (sender) 388 string_upper(sender, sender); 389 else 390 sender = cmm_default_sender; 391 392 rc = smsg_register_callback(SMSG_PREFIX, cmm_smsg_target); 393 if (rc < 0) 394 goto out_smsg; 395 #endif 396 rc = register_oom_notifier(&cmm_oom_nb); 397 if (rc < 0) 398 goto out_oom_notify; 399 cmm_thread_ptr = kthread_run(cmm_thread, NULL, "cmmthread"); 400 if (!IS_ERR(cmm_thread_ptr)) 401 return 0; 402 403 rc = PTR_ERR(cmm_thread_ptr); 404 unregister_oom_notifier(&cmm_oom_nb); 405 out_oom_notify: 406 #ifdef CONFIG_CMM_IUCV 407 smsg_unregister_callback(SMSG_PREFIX, cmm_smsg_target); 408 out_smsg: 409 #endif 410 unregister_sysctl_table(cmm_sysctl_header); 411 out_sysctl: 412 del_timer_sync(&cmm_timer); 413 return rc; 414 } 415 module_init(cmm_init); 416 417 static void __exit cmm_exit(void) 418 { 419 unregister_sysctl_table(cmm_sysctl_header); 420 #ifdef CONFIG_CMM_IUCV 421 smsg_unregister_callback(SMSG_PREFIX, cmm_smsg_target); 422 #endif 423 unregister_oom_notifier(&cmm_oom_nb); 424 kthread_stop(cmm_thread_ptr); 425 del_timer_sync(&cmm_timer); 426 cmm_free_pages(cmm_pages, &cmm_pages, &cmm_page_list); 427 cmm_free_pages(cmm_timed_pages, &cmm_timed_pages, &cmm_timed_page_list); 428 } 429 module_exit(cmm_exit); 430 431 MODULE_LICENSE("GPL"); 432