Brian King | 84af458 | 2008-07-24 04:30:29 +1000 | [diff] [blame] | 1 | /* |
| 2 | * Collaborative memory management interface. |
| 3 | * |
| 4 | * Copyright (C) 2008 IBM Corporation |
| 5 | * Author(s): Brian King (brking@linux.vnet.ibm.com), |
| 6 | * |
| 7 | * This program is free software; you can redistribute it and/or modify |
| 8 | * it under the terms of the GNU General Public License as published by |
| 9 | * the Free Software Foundation; either version 2 of the License, or |
| 10 | * (at your option) any later version. |
| 11 | * |
| 12 | * This program is distributed in the hope that it will be useful, |
| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | * GNU General Public License for more details. |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License |
| 18 | * along with this program; if not, write to the Free Software |
| 19 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| 20 | * |
| 21 | */ |
| 22 | |
| 23 | #include <linux/ctype.h> |
| 24 | #include <linux/delay.h> |
| 25 | #include <linux/errno.h> |
| 26 | #include <linux/fs.h> |
| 27 | #include <linux/init.h> |
| 28 | #include <linux/kthread.h> |
| 29 | #include <linux/module.h> |
| 30 | #include <linux/oom.h> |
| 31 | #include <linux/sched.h> |
| 32 | #include <linux/stringify.h> |
| 33 | #include <linux/swap.h> |
| 34 | #include <linux/sysdev.h> |
| 35 | #include <asm/firmware.h> |
| 36 | #include <asm/hvcall.h> |
| 37 | #include <asm/mmu.h> |
| 38 | #include <asm/pgalloc.h> |
| 39 | #include <asm/uaccess.h> |
| 40 | |
| 41 | #include "plpar_wrappers.h" |
| 42 | |
| 43 | #define CMM_DRIVER_VERSION "1.0.0" |
| 44 | #define CMM_DEFAULT_DELAY 1 |
| 45 | #define CMM_DEBUG 0 |
| 46 | #define CMM_DISABLE 0 |
| 47 | #define CMM_OOM_KB 1024 |
| 48 | #define CMM_MIN_MEM_MB 256 |
| 49 | #define KB2PAGES(_p) ((_p)>>(PAGE_SHIFT-10)) |
| 50 | #define PAGES2KB(_p) ((_p)<<(PAGE_SHIFT-10)) |
| 51 | |
| 52 | static unsigned int delay = CMM_DEFAULT_DELAY; |
| 53 | static unsigned int oom_kb = CMM_OOM_KB; |
| 54 | static unsigned int cmm_debug = CMM_DEBUG; |
| 55 | static unsigned int cmm_disabled = CMM_DISABLE; |
| 56 | static unsigned long min_mem_mb = CMM_MIN_MEM_MB; |
| 57 | static struct sys_device cmm_sysdev; |
| 58 | |
| 59 | MODULE_AUTHOR("Brian King <brking@linux.vnet.ibm.com>"); |
| 60 | MODULE_DESCRIPTION("IBM System p Collaborative Memory Manager"); |
| 61 | MODULE_LICENSE("GPL"); |
| 62 | MODULE_VERSION(CMM_DRIVER_VERSION); |
| 63 | |
| 64 | module_param_named(delay, delay, uint, S_IRUGO | S_IWUSR); |
| 65 | MODULE_PARM_DESC(delay, "Delay (in seconds) between polls to query hypervisor paging requests. " |
| 66 | "[Default=" __stringify(CMM_DEFAULT_DELAY) "]"); |
| 67 | module_param_named(oom_kb, oom_kb, uint, S_IRUGO | S_IWUSR); |
| 68 | MODULE_PARM_DESC(oom_kb, "Amount of memory in kb to free on OOM. " |
| 69 | "[Default=" __stringify(CMM_OOM_KB) "]"); |
| 70 | module_param_named(min_mem_mb, min_mem_mb, ulong, S_IRUGO | S_IWUSR); |
| 71 | MODULE_PARM_DESC(min_mem_mb, "Minimum amount of memory (in MB) to not balloon. " |
| 72 | "[Default=" __stringify(CMM_MIN_MEM_MB) "]"); |
| 73 | module_param_named(debug, cmm_debug, uint, S_IRUGO | S_IWUSR); |
| 74 | MODULE_PARM_DESC(debug, "Enable module debugging logging. Set to 1 to enable. " |
| 75 | "[Default=" __stringify(CMM_DEBUG) "]"); |
| 76 | |
| 77 | #define CMM_NR_PAGES ((PAGE_SIZE - sizeof(void *) - sizeof(unsigned long)) / sizeof(unsigned long)) |
| 78 | |
| 79 | #define cmm_dbg(...) if (cmm_debug) { printk(KERN_INFO "cmm: "__VA_ARGS__); } |
| 80 | |
| 81 | struct cmm_page_array { |
| 82 | struct cmm_page_array *next; |
| 83 | unsigned long index; |
| 84 | unsigned long page[CMM_NR_PAGES]; |
| 85 | }; |
| 86 | |
| 87 | static unsigned long loaned_pages; |
| 88 | static unsigned long loaned_pages_target; |
| 89 | static unsigned long oom_freed_pages; |
| 90 | |
| 91 | static struct cmm_page_array *cmm_page_list; |
| 92 | static DEFINE_SPINLOCK(cmm_lock); |
| 93 | |
| 94 | static struct task_struct *cmm_thread_ptr; |
| 95 | |
| 96 | /** |
| 97 | * cmm_alloc_pages - Allocate pages and mark them as loaned |
| 98 | * @nr: number of pages to allocate |
| 99 | * |
| 100 | * Return value: |
| 101 | * number of pages requested to be allocated which were not |
| 102 | **/ |
| 103 | static long cmm_alloc_pages(long nr) |
| 104 | { |
| 105 | struct cmm_page_array *pa, *npa; |
| 106 | unsigned long addr; |
| 107 | long rc; |
| 108 | |
| 109 | cmm_dbg("Begin request for %ld pages\n", nr); |
| 110 | |
| 111 | while (nr) { |
| 112 | addr = __get_free_page(GFP_NOIO | __GFP_NOWARN | |
| 113 | __GFP_NORETRY | __GFP_NOMEMALLOC); |
| 114 | if (!addr) |
| 115 | break; |
| 116 | spin_lock(&cmm_lock); |
| 117 | pa = cmm_page_list; |
| 118 | if (!pa || pa->index >= CMM_NR_PAGES) { |
| 119 | /* Need a new page for the page list. */ |
| 120 | spin_unlock(&cmm_lock); |
| 121 | npa = (struct cmm_page_array *)__get_free_page(GFP_NOIO | __GFP_NOWARN | |
| 122 | __GFP_NORETRY | __GFP_NOMEMALLOC); |
| 123 | if (!npa) { |
| 124 | pr_info("%s: Can not allocate new page list\n", __FUNCTION__); |
| 125 | free_page(addr); |
| 126 | break; |
| 127 | } |
| 128 | spin_lock(&cmm_lock); |
| 129 | pa = cmm_page_list; |
| 130 | |
| 131 | if (!pa || pa->index >= CMM_NR_PAGES) { |
| 132 | npa->next = pa; |
| 133 | npa->index = 0; |
| 134 | pa = npa; |
| 135 | cmm_page_list = pa; |
| 136 | } else |
| 137 | free_page((unsigned long) npa); |
| 138 | } |
| 139 | |
| 140 | if ((rc = plpar_page_set_loaned(__pa(addr)))) { |
| 141 | pr_err("%s: Can not set page to loaned. rc=%ld\n", __FUNCTION__, rc); |
| 142 | spin_unlock(&cmm_lock); |
| 143 | free_page(addr); |
| 144 | break; |
| 145 | } |
| 146 | |
| 147 | pa->page[pa->index++] = addr; |
| 148 | loaned_pages++; |
| 149 | totalram_pages--; |
| 150 | spin_unlock(&cmm_lock); |
| 151 | nr--; |
| 152 | } |
| 153 | |
| 154 | cmm_dbg("End request with %ld pages unfulfilled\n", nr); |
| 155 | return nr; |
| 156 | } |
| 157 | |
| 158 | /** |
| 159 | * cmm_free_pages - Free pages and mark them as active |
| 160 | * @nr: number of pages to free |
| 161 | * |
| 162 | * Return value: |
| 163 | * number of pages requested to be freed which were not |
| 164 | **/ |
| 165 | static long cmm_free_pages(long nr) |
| 166 | { |
| 167 | struct cmm_page_array *pa; |
| 168 | unsigned long addr; |
| 169 | |
| 170 | cmm_dbg("Begin free of %ld pages.\n", nr); |
| 171 | spin_lock(&cmm_lock); |
| 172 | pa = cmm_page_list; |
| 173 | while (nr) { |
| 174 | if (!pa || pa->index <= 0) |
| 175 | break; |
| 176 | addr = pa->page[--pa->index]; |
| 177 | |
| 178 | if (pa->index == 0) { |
| 179 | pa = pa->next; |
| 180 | free_page((unsigned long) cmm_page_list); |
| 181 | cmm_page_list = pa; |
| 182 | } |
| 183 | |
| 184 | plpar_page_set_active(__pa(addr)); |
| 185 | free_page(addr); |
| 186 | loaned_pages--; |
| 187 | nr--; |
| 188 | totalram_pages++; |
| 189 | } |
| 190 | spin_unlock(&cmm_lock); |
| 191 | cmm_dbg("End request with %ld pages unfulfilled\n", nr); |
| 192 | return nr; |
| 193 | } |
| 194 | |
| 195 | /** |
| 196 | * cmm_oom_notify - OOM notifier |
| 197 | * @self: notifier block struct |
| 198 | * @dummy: not used |
| 199 | * @parm: returned - number of pages freed |
| 200 | * |
| 201 | * Return value: |
| 202 | * NOTIFY_OK |
| 203 | **/ |
| 204 | static int cmm_oom_notify(struct notifier_block *self, |
| 205 | unsigned long dummy, void *parm) |
| 206 | { |
| 207 | unsigned long *freed = parm; |
| 208 | long nr = KB2PAGES(oom_kb); |
| 209 | |
| 210 | cmm_dbg("OOM processing started\n"); |
| 211 | nr = cmm_free_pages(nr); |
| 212 | loaned_pages_target = loaned_pages; |
| 213 | *freed += KB2PAGES(oom_kb) - nr; |
| 214 | oom_freed_pages += KB2PAGES(oom_kb) - nr; |
| 215 | cmm_dbg("OOM processing complete\n"); |
| 216 | return NOTIFY_OK; |
| 217 | } |
| 218 | |
| 219 | /** |
| 220 | * cmm_get_mpp - Read memory performance parameters |
| 221 | * |
| 222 | * Makes hcall to query the current page loan request from the hypervisor. |
| 223 | * |
| 224 | * Return value: |
| 225 | * nothing |
| 226 | **/ |
| 227 | static void cmm_get_mpp(void) |
| 228 | { |
| 229 | int rc; |
| 230 | struct hvcall_mpp_data mpp_data; |
| 231 | unsigned long active_pages_target; |
| 232 | signed long page_loan_request; |
| 233 | |
| 234 | rc = h_get_mpp(&mpp_data); |
| 235 | |
| 236 | if (rc != H_SUCCESS) |
| 237 | return; |
| 238 | |
| 239 | page_loan_request = div_s64((s64)mpp_data.loan_request, PAGE_SIZE); |
| 240 | loaned_pages_target = page_loan_request + loaned_pages; |
| 241 | if (loaned_pages_target > oom_freed_pages) |
| 242 | loaned_pages_target -= oom_freed_pages; |
| 243 | else |
| 244 | loaned_pages_target = 0; |
| 245 | |
| 246 | active_pages_target = totalram_pages + loaned_pages - loaned_pages_target; |
| 247 | |
| 248 | if ((min_mem_mb * 1024 * 1024) > (active_pages_target * PAGE_SIZE)) |
| 249 | loaned_pages_target = totalram_pages + loaned_pages - |
| 250 | ((min_mem_mb * 1024 * 1024) / PAGE_SIZE); |
| 251 | |
| 252 | cmm_dbg("delta = %ld, loaned = %lu, target = %lu, oom = %lu, totalram = %lu\n", |
| 253 | page_loan_request, loaned_pages, loaned_pages_target, |
| 254 | oom_freed_pages, totalram_pages); |
| 255 | } |
| 256 | |
| 257 | static struct notifier_block cmm_oom_nb = { |
| 258 | .notifier_call = cmm_oom_notify |
| 259 | }; |
| 260 | |
| 261 | /** |
| 262 | * cmm_thread - CMM task thread |
| 263 | * @dummy: not used |
| 264 | * |
| 265 | * Return value: |
| 266 | * 0 |
| 267 | **/ |
| 268 | static int cmm_thread(void *dummy) |
| 269 | { |
| 270 | unsigned long timeleft; |
| 271 | |
| 272 | while (1) { |
| 273 | timeleft = msleep_interruptible(delay * 1000); |
| 274 | |
| 275 | if (kthread_should_stop() || timeleft) { |
| 276 | loaned_pages_target = loaned_pages; |
| 277 | break; |
| 278 | } |
| 279 | |
| 280 | cmm_get_mpp(); |
| 281 | |
| 282 | if (loaned_pages_target > loaned_pages) { |
| 283 | if (cmm_alloc_pages(loaned_pages_target - loaned_pages)) |
| 284 | loaned_pages_target = loaned_pages; |
| 285 | } else if (loaned_pages_target < loaned_pages) |
| 286 | cmm_free_pages(loaned_pages - loaned_pages_target); |
| 287 | } |
| 288 | return 0; |
| 289 | } |
| 290 | |
| 291 | #define CMM_SHOW(name, format, args...) \ |
Stephen Rothwell | 3cee67f | 2008-07-28 00:51:02 +1000 | [diff] [blame^] | 292 | static ssize_t show_##name(struct sys_device *dev, \ |
| 293 | struct sysdev_attribute *attr, \ |
| 294 | char *buf) \ |
Brian King | 84af458 | 2008-07-24 04:30:29 +1000 | [diff] [blame] | 295 | { \ |
| 296 | return sprintf(buf, format, ##args); \ |
| 297 | } \ |
| 298 | static SYSDEV_ATTR(name, S_IRUGO, show_##name, NULL) |
| 299 | |
| 300 | CMM_SHOW(loaned_kb, "%lu\n", PAGES2KB(loaned_pages)); |
| 301 | CMM_SHOW(loaned_target_kb, "%lu\n", PAGES2KB(loaned_pages_target)); |
| 302 | |
Stephen Rothwell | 3cee67f | 2008-07-28 00:51:02 +1000 | [diff] [blame^] | 303 | static ssize_t show_oom_pages(struct sys_device *dev, |
| 304 | struct sysdev_attribute *attr, char *buf) |
Brian King | 84af458 | 2008-07-24 04:30:29 +1000 | [diff] [blame] | 305 | { |
| 306 | return sprintf(buf, "%lu\n", PAGES2KB(oom_freed_pages)); |
| 307 | } |
| 308 | |
| 309 | static ssize_t store_oom_pages(struct sys_device *dev, |
Stephen Rothwell | 3cee67f | 2008-07-28 00:51:02 +1000 | [diff] [blame^] | 310 | struct sysdev_attribute *attr, |
Brian King | 84af458 | 2008-07-24 04:30:29 +1000 | [diff] [blame] | 311 | const char *buf, size_t count) |
| 312 | { |
| 313 | unsigned long val = simple_strtoul (buf, NULL, 10); |
| 314 | |
| 315 | if (!capable(CAP_SYS_ADMIN)) |
| 316 | return -EPERM; |
| 317 | if (val != 0) |
| 318 | return -EBADMSG; |
| 319 | |
| 320 | oom_freed_pages = 0; |
| 321 | return count; |
| 322 | } |
| 323 | |
| 324 | static SYSDEV_ATTR(oom_freed_kb, S_IWUSR| S_IRUGO, |
| 325 | show_oom_pages, store_oom_pages); |
| 326 | |
| 327 | static struct sysdev_attribute *cmm_attrs[] = { |
| 328 | &attr_loaned_kb, |
| 329 | &attr_loaned_target_kb, |
| 330 | &attr_oom_freed_kb, |
| 331 | }; |
| 332 | |
| 333 | static struct sysdev_class cmm_sysdev_class = { |
| 334 | .name = "cmm", |
| 335 | }; |
| 336 | |
| 337 | /** |
| 338 | * cmm_sysfs_register - Register with sysfs |
| 339 | * |
| 340 | * Return value: |
| 341 | * 0 on success / other on failure |
| 342 | **/ |
| 343 | static int cmm_sysfs_register(struct sys_device *sysdev) |
| 344 | { |
| 345 | int i, rc; |
| 346 | |
| 347 | if ((rc = sysdev_class_register(&cmm_sysdev_class))) |
| 348 | return rc; |
| 349 | |
| 350 | sysdev->id = 0; |
| 351 | sysdev->cls = &cmm_sysdev_class; |
| 352 | |
| 353 | if ((rc = sysdev_register(sysdev))) |
| 354 | goto class_unregister; |
| 355 | |
| 356 | for (i = 0; i < ARRAY_SIZE(cmm_attrs); i++) { |
| 357 | if ((rc = sysdev_create_file(sysdev, cmm_attrs[i]))) |
| 358 | goto fail; |
| 359 | } |
| 360 | |
| 361 | return 0; |
| 362 | |
| 363 | fail: |
| 364 | while (--i >= 0) |
| 365 | sysdev_remove_file(sysdev, cmm_attrs[i]); |
| 366 | sysdev_unregister(sysdev); |
| 367 | class_unregister: |
| 368 | sysdev_class_unregister(&cmm_sysdev_class); |
| 369 | return rc; |
| 370 | } |
| 371 | |
| 372 | /** |
| 373 | * cmm_unregister_sysfs - Unregister from sysfs |
| 374 | * |
| 375 | **/ |
| 376 | static void cmm_unregister_sysfs(struct sys_device *sysdev) |
| 377 | { |
| 378 | int i; |
| 379 | |
| 380 | for (i = 0; i < ARRAY_SIZE(cmm_attrs); i++) |
| 381 | sysdev_remove_file(sysdev, cmm_attrs[i]); |
| 382 | sysdev_unregister(sysdev); |
| 383 | sysdev_class_unregister(&cmm_sysdev_class); |
| 384 | } |
| 385 | |
| 386 | /** |
| 387 | * cmm_init - Module initialization |
| 388 | * |
| 389 | * Return value: |
| 390 | * 0 on success / other on failure |
| 391 | **/ |
| 392 | static int cmm_init(void) |
| 393 | { |
| 394 | int rc = -ENOMEM; |
| 395 | |
| 396 | if (!firmware_has_feature(FW_FEATURE_CMO)) |
| 397 | return -EOPNOTSUPP; |
| 398 | |
| 399 | if ((rc = register_oom_notifier(&cmm_oom_nb)) < 0) |
| 400 | return rc; |
| 401 | |
| 402 | if ((rc = cmm_sysfs_register(&cmm_sysdev))) |
| 403 | goto out_oom_notifier; |
| 404 | |
| 405 | if (cmm_disabled) |
| 406 | return rc; |
| 407 | |
| 408 | cmm_thread_ptr = kthread_run(cmm_thread, NULL, "cmmthread"); |
| 409 | if (IS_ERR(cmm_thread_ptr)) { |
| 410 | rc = PTR_ERR(cmm_thread_ptr); |
| 411 | goto out_unregister_sysfs; |
| 412 | } |
| 413 | |
| 414 | return rc; |
| 415 | |
| 416 | out_unregister_sysfs: |
| 417 | cmm_unregister_sysfs(&cmm_sysdev); |
| 418 | out_oom_notifier: |
| 419 | unregister_oom_notifier(&cmm_oom_nb); |
| 420 | return rc; |
| 421 | } |
| 422 | |
| 423 | /** |
| 424 | * cmm_exit - Module exit |
| 425 | * |
| 426 | * Return value: |
| 427 | * nothing |
| 428 | **/ |
| 429 | static void cmm_exit(void) |
| 430 | { |
| 431 | if (cmm_thread_ptr) |
| 432 | kthread_stop(cmm_thread_ptr); |
| 433 | unregister_oom_notifier(&cmm_oom_nb); |
| 434 | cmm_free_pages(loaned_pages); |
| 435 | cmm_unregister_sysfs(&cmm_sysdev); |
| 436 | } |
| 437 | |
| 438 | /** |
| 439 | * cmm_set_disable - Disable/Enable CMM |
| 440 | * |
| 441 | * Return value: |
| 442 | * 0 on success / other on failure |
| 443 | **/ |
| 444 | static int cmm_set_disable(const char *val, struct kernel_param *kp) |
| 445 | { |
| 446 | int disable = simple_strtoul(val, NULL, 10); |
| 447 | |
| 448 | if (disable != 0 && disable != 1) |
| 449 | return -EINVAL; |
| 450 | |
| 451 | if (disable && !cmm_disabled) { |
| 452 | if (cmm_thread_ptr) |
| 453 | kthread_stop(cmm_thread_ptr); |
| 454 | cmm_thread_ptr = NULL; |
| 455 | cmm_free_pages(loaned_pages); |
| 456 | } else if (!disable && cmm_disabled) { |
| 457 | cmm_thread_ptr = kthread_run(cmm_thread, NULL, "cmmthread"); |
| 458 | if (IS_ERR(cmm_thread_ptr)) |
| 459 | return PTR_ERR(cmm_thread_ptr); |
| 460 | } |
| 461 | |
| 462 | cmm_disabled = disable; |
| 463 | return 0; |
| 464 | } |
| 465 | |
| 466 | module_param_call(disable, cmm_set_disable, param_get_uint, |
| 467 | &cmm_disabled, S_IRUGO | S_IWUSR); |
| 468 | MODULE_PARM_DESC(disable, "Disable CMM. Set to 1 to disable. " |
| 469 | "[Default=" __stringify(CMM_DISABLE) "]"); |
| 470 | |
| 471 | module_init(cmm_init); |
| 472 | module_exit(cmm_exit); |