arch/powerpc/platforms/pseries/cmm.c

   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/reboot.h>
  32 #include <linux/sched.h>
  33 #include <linux/stringify.h>
  34 #include <linux/swap.h>
  35 #include <linux/sysdev.h>
  36 #include <asm/firmware.h>
  37 #include <asm/hvcall.h>
  38 #include <asm/mmu.h>
  39 #include <asm/pgalloc.h>
  40 #include <asm/uaccess.h>
  41
  42 #include "plpar_wrappers.h"
  43
  44 #define CMM_DRIVER_VERSION      "1.0.0"
  45 #define CMM_DEFAULT_DELAY       1
  46 #define CMM_DEBUG                       0
  47 #define CMM_DISABLE             0
  48 #define CMM_OOM_KB              1024
  49 #define CMM_MIN_MEM_MB          256
  50 #define KB2PAGES(_p)            ((_p)>>(PAGE_SHIFT-10))
  51 #define PAGES2KB(_p)            ((_p)<<(PAGE_SHIFT-10))
  52
  53 static unsigned int delay = CMM_DEFAULT_DELAY;
  54 static unsigned int oom_kb = CMM_OOM_KB;
  55 static unsigned int cmm_debug = CMM_DEBUG;
  56 static unsigned int cmm_disabled = CMM_DISABLE;
  57 static unsigned long min_mem_mb = CMM_MIN_MEM_MB;
  58 static struct sys_device cmm_sysdev;
  59
  60 MODULE_AUTHOR("Brian King <brking@linux.vnet.ibm.com>");
  61 MODULE_DESCRIPTION("IBM System p Collaborative Memory Manager");
  62 MODULE_LICENSE("GPL");
  63 MODULE_VERSION(CMM_DRIVER_VERSION);
  64
  65 module_param_named(delay, delay, uint, S_IRUGO | S_IWUSR);
  66 MODULE_PARM_DESC(delay, "Delay (in seconds) between polls to query hypervisor paging requests. "
  67                  "[Default=" __stringify(CMM_DEFAULT_DELAY) "]");
  68 module_param_named(oom_kb, oom_kb, uint, S_IRUGO | S_IWUSR);
  69 MODULE_PARM_DESC(oom_kb, "Amount of memory in kb to free on OOM. "
  70                  "[Default=" __stringify(CMM_OOM_KB) "]");
  71 module_param_named(min_mem_mb, min_mem_mb, ulong, S_IRUGO | S_IWUSR);
  72 MODULE_PARM_DESC(min_mem_mb, "Minimum amount of memory (in MB) to not balloon. "
  73                  "[Default=" __stringify(CMM_MIN_MEM_MB) "]");
  74 module_param_named(debug, cmm_debug, uint, S_IRUGO | S_IWUSR);
  75 MODULE_PARM_DESC(debug, "Enable module debugging logging. Set to 1 to enable. "
  76                  "[Default=" __stringify(CMM_DEBUG) "]");
  77
  78 #define CMM_NR_PAGES ((PAGE_SIZE - sizeof(void *) - sizeof(unsigned long)) / sizeof(unsigned long))
  79
  80 #define cmm_dbg(...) if (cmm_debug) { printk(KERN_INFO "cmm: "__VA_ARGS__); }
  81
  82 struct cmm_page_array {
  83         struct cmm_page_array *next;
  84         unsigned long index;
  85         unsigned long page[CMM_NR_PAGES];
  86 };
  87
  88 static unsigned long loaned_pages;
  89 static unsigned long loaned_pages_target;
  90 static unsigned long oom_freed_pages;
  91
  92 static struct cmm_page_array *cmm_page_list;
  93 static DEFINE_SPINLOCK(cmm_lock);
  94
  95 static struct task_struct *cmm_thread_ptr;
  96
  97 /**
  98  * cmm_alloc_pages - Allocate pages and mark them as loaned
  99  * @nr: number of pages to allocate
 100  *
 101  * Return value:
 102  *      number of pages requested to be allocated which were not
 103  **/
 104 static long cmm_alloc_pages(long nr)
 105 {
 106         struct cmm_page_array *pa, *npa;
 107         unsigned long addr;
 108         long rc;
 109
 110         cmm_dbg("Begin request for %ld pages\n", nr);
 111
 112         while (nr) {
 113                 addr = __get_free_page(GFP_NOIO | __GFP_NOWARN |
 114                                        __GFP_NORETRY | __GFP_NOMEMALLOC);
 115                 if (!addr)
 116                         break;
 117                 spin_lock(&cmm_lock);
 118                 pa = cmm_page_list;
 119                 if (!pa || pa->index >= CMM_NR_PAGES) {
 120                         /* Need a new page for the page list. */
 121                         spin_unlock(&cmm_lock);
 122                         npa = (struct cmm_page_array *)__get_free_page(GFP_NOIO | __GFP_NOWARN |
 123                                                                        __GFP_NORETRY | __GFP_NOMEMALLOC);
 124                         if (!npa) {
 125                                 pr_info("%s: Can not allocate new page list\n", __func__);
 126                                 free_page(addr);
 127                                 break;
 128                         }
 129                         spin_lock(&cmm_lock);
 130                         pa = cmm_page_list;
 131
 132                         if (!pa || pa->index >= CMM_NR_PAGES) {
 133                                 npa->next = pa;
 134                                 npa->index = 0;
 135                                 pa = npa;
 136                                 cmm_page_list = pa;
 137                         } else
 138                                 free_page((unsigned long) npa);
 139                 }
 140
 141                 if ((rc = plpar_page_set_loaned(__pa(addr)))) {
 142                         pr_err("%s: Can not set page to loaned. rc=%ld\n", __func__, rc);
 143                         spin_unlock(&cmm_lock);
 144                         free_page(addr);
 145                         break;
 146                 }
 147
 148                 pa->page[pa->index++] = addr;
 149                 loaned_pages++;
 150                 totalram_pages--;
 151                 spin_unlock(&cmm_lock);
 152                 nr--;
 153         }
 154
 155         cmm_dbg("End request with %ld pages unfulfilled\n", nr);
 156         return nr;
 157 }
 158
 159 /**
 160  * cmm_free_pages - Free pages and mark them as active
 161  * @nr: number of pages to free
 162  *
 163  * Return value:
 164  *      number of pages requested to be freed which were not
 165  **/
 166 static long cmm_free_pages(long nr)
 167 {
 168         struct cmm_page_array *pa;
 169         unsigned long addr;
 170
 171         cmm_dbg("Begin free of %ld pages.\n", nr);
 172         spin_lock(&cmm_lock);
 173         pa = cmm_page_list;
 174         while (nr) {
 175                 if (!pa || pa->index <= 0)
 176                         break;
 177                 addr = pa->page[--pa->index];
 178
 179                 if (pa->index == 0) {
 180                         pa = pa->next;
 181                         free_page((unsigned long) cmm_page_list);
 182                         cmm_page_list = pa;
 183                 }
 184
 185                 plpar_page_set_active(__pa(addr));
 186                 free_page(addr);
 187                 loaned_pages--;
 188                 nr--;
 189                 totalram_pages++;
 190         }
 191         spin_unlock(&cmm_lock);
 192         cmm_dbg("End request with %ld pages unfulfilled\n", nr);
 193         return nr;
 194 }
 195
 196 /**
 197  * cmm_oom_notify - OOM notifier
 198  * @self:       notifier block struct
 199  * @dummy:      not used
 200  * @parm:       returned - number of pages freed
 201  *
 202  * Return value:
 203  *      NOTIFY_OK
 204  **/
 205 static int cmm_oom_notify(struct notifier_block *self,
 206                           unsigned long dummy, void *parm)
 207 {
 208         unsigned long *freed = parm;
 209         long nr = KB2PAGES(oom_kb);
 210
 211         cmm_dbg("OOM processing started\n");
 212         nr = cmm_free_pages(nr);
 213         loaned_pages_target = loaned_pages;
 214         *freed += KB2PAGES(oom_kb) - nr;
 215         oom_freed_pages += KB2PAGES(oom_kb) - nr;
 216         cmm_dbg("OOM processing complete\n");
 217         return NOTIFY_OK;
 218 }
 219
 220 /**
 221  * cmm_get_mpp - Read memory performance parameters
 222  *
 223  * Makes hcall to query the current page loan request from the hypervisor.
 224  *
 225  * Return value:
 226  *      nothing
 227  **/
 228 static void cmm_get_mpp(void)
 229 {
 230         int rc;
 231         struct hvcall_mpp_data mpp_data;
 232         signed long active_pages_target, page_loan_request, target;
 233         signed long total_pages = totalram_pages + loaned_pages;
 234         signed long min_mem_pages = (min_mem_mb * 1024 * 1024) / PAGE_SIZE;
 235
 236         rc = h_get_mpp(&mpp_data);
 237
 238         if (rc != H_SUCCESS)
 239                 return;
 240
 241         page_loan_request = div_s64((s64)mpp_data.loan_request, PAGE_SIZE);
 242         target = page_loan_request + (signed long)loaned_pages;
 243
 244         if (target < 0 || total_pages < min_mem_pages)
 245                 target = 0;
 246
 247         if (target > oom_freed_pages)
 248                 target -= oom_freed_pages;
 249         else
 250                 target = 0;
 251
 252         active_pages_target = total_pages - target;
 253
 254         if (min_mem_pages > active_pages_target)
 255                 target = total_pages - min_mem_pages;
 256
 257         if (target < 0)
 258                 target = 0;
 259
 260         loaned_pages_target = target;
 261
 262         cmm_dbg("delta = %ld, loaned = %lu, target = %lu, oom = %lu, totalram = %lu\n",
 263                 page_loan_request, loaned_pages, loaned_pages_target,
 264                 oom_freed_pages, totalram_pages);
 265 }
 266
 267 static struct notifier_block cmm_oom_nb = {
 268         .notifier_call = cmm_oom_notify
 269 };
 270
 271 /**
 272  * cmm_thread - CMM task thread
 273  * @dummy:      not used
 274  *
 275  * Return value:
 276  *      0
 277  **/
 278 static int cmm_thread(void *dummy)
 279 {
 280         unsigned long timeleft;
 281
 282         while (1) {
 283                 timeleft = msleep_interruptible(delay * 1000);
 284
 285                 if (kthread_should_stop() || timeleft) {
 286                         loaned_pages_target = loaned_pages;
 287                         break;
 288                 }
 289
 290                 cmm_get_mpp();
 291
 292                 if (loaned_pages_target > loaned_pages) {
 293                         if (cmm_alloc_pages(loaned_pages_target - loaned_pages))
 294                                 loaned_pages_target = loaned_pages;
 295                 } else if (loaned_pages_target < loaned_pages)
 296                         cmm_free_pages(loaned_pages - loaned_pages_target);
 297         }
 298         return 0;
 299 }
 300
 301 #define CMM_SHOW(name, format, args...)                 \
 302         static ssize_t show_##name(struct sys_device *dev,      \
 303                                    struct sysdev_attribute *attr,       \
 304                                    char *buf)                   \
 305         {                                                       \
 306                 return sprintf(buf, format, ##args);            \
 307         }                                                       \
 308         static SYSDEV_ATTR(name, S_IRUGO, show_##name, NULL)
 309
 310 CMM_SHOW(loaned_kb, "%lu\n", PAGES2KB(loaned_pages));
 311 CMM_SHOW(loaned_target_kb, "%lu\n", PAGES2KB(loaned_pages_target));
 312
 313 static ssize_t show_oom_pages(struct sys_device *dev,
 314                               struct sysdev_attribute *attr, char *buf)
 315 {
 316         return sprintf(buf, "%lu\n", PAGES2KB(oom_freed_pages));
 317 }
 318
 319 static ssize_t store_oom_pages(struct sys_device *dev,
 320                                struct sysdev_attribute *attr,
 321                                const char *buf, size_t count)
 322 {
 323         unsigned long val = simple_strtoul (buf, NULL, 10);
 324
 325         if (!capable(CAP_SYS_ADMIN))
 326                 return -EPERM;
 327         if (val != 0)
 328                 return -EBADMSG;
 329
 330         oom_freed_pages = 0;
 331         return count;
 332 }
 333
 334 static SYSDEV_ATTR(oom_freed_kb, S_IWUSR| S_IRUGO,
 335                    show_oom_pages, store_oom_pages);
 336
 337 static struct sysdev_attribute *cmm_attrs[] = {
 338         &attr_loaned_kb,
 339         &attr_loaned_target_kb,
 340         &attr_oom_freed_kb,
 341 };
 342
 343 static struct sysdev_class cmm_sysdev_class = {
 344         .name = "cmm",
 345 };
 346
 347 /**
 348  * cmm_sysfs_register - Register with sysfs
 349  *
 350  * Return value:
 351  *      0 on success / other on failure
 352  **/
 353 static int cmm_sysfs_register(struct sys_device *sysdev)
 354 {
 355         int i, rc;
 356
 357         if ((rc = sysdev_class_register(&cmm_sysdev_class)))
 358                 return rc;
 359
 360         sysdev->id = 0;
 361         sysdev->cls = &cmm_sysdev_class;
 362
 363         if ((rc = sysdev_register(sysdev)))
 364                 goto class_unregister;
 365
 366         for (i = 0; i < ARRAY_SIZE(cmm_attrs); i++) {
 367                 if ((rc = sysdev_create_file(sysdev, cmm_attrs[i])))
 368                         goto fail;
 369         }
 370
 371         return 0;
 372
 373 fail:
 374         while (--i >= 0)
 375                 sysdev_remove_file(sysdev, cmm_attrs[i]);
 376         sysdev_unregister(sysdev);
 377 class_unregister:
 378         sysdev_class_unregister(&cmm_sysdev_class);
 379         return rc;
 380 }
 381
 382 /**
 383  * cmm_unregister_sysfs - Unregister from sysfs
 384  *
 385  **/
 386 static void cmm_unregister_sysfs(struct sys_device *sysdev)
 387 {
 388         int i;
 389
 390         for (i = 0; i < ARRAY_SIZE(cmm_attrs); i++)
 391                 sysdev_remove_file(sysdev, cmm_attrs[i]);
 392         sysdev_unregister(sysdev);
 393         sysdev_class_unregister(&cmm_sysdev_class);
 394 }
 395
 396 /**
 397  * cmm_reboot_notifier - Make sure pages are not still marked as "loaned"
 398  *
 399  **/
 400 static int cmm_reboot_notifier(struct notifier_block *nb,
 401                                unsigned long action, void *unused)
 402 {
 403         if (action == SYS_RESTART) {
 404                 if (cmm_thread_ptr)
 405                         kthread_stop(cmm_thread_ptr);
 406                 cmm_thread_ptr = NULL;
 407                 cmm_free_pages(loaned_pages);
 408         }
 409         return NOTIFY_DONE;
 410 }
 411
 412 static struct notifier_block cmm_reboot_nb = {
 413         .notifier_call = cmm_reboot_notifier,
 414 };
 415
 416 /**
 417  * cmm_init - Module initialization
 418  *
 419  * Return value:
 420  *      0 on success / other on failure
 421  **/
 422 static int cmm_init(void)
 423 {
 424         int rc = -ENOMEM;
 425
 426         if (!firmware_has_feature(FW_FEATURE_CMO))
 427                 return -EOPNOTSUPP;
 428
 429         if ((rc = register_oom_notifier(&cmm_oom_nb)) < 0)
 430                 return rc;
 431
 432         if ((rc = register_reboot_notifier(&cmm_reboot_nb)))
 433                 goto out_oom_notifier;
 434
 435         if ((rc = cmm_sysfs_register(&cmm_sysdev)))
 436                 goto out_reboot_notifier;
 437
 438         if (cmm_disabled)
 439                 return rc;
 440
 441         cmm_thread_ptr = kthread_run(cmm_thread, NULL, "cmmthread");
 442         if (IS_ERR(cmm_thread_ptr)) {
 443                 rc = PTR_ERR(cmm_thread_ptr);
 444                 goto out_unregister_sysfs;
 445         }
 446
 447         return rc;
 448
 449 out_unregister_sysfs:
 450         cmm_unregister_sysfs(&cmm_sysdev);
 451 out_reboot_notifier:
 452         unregister_reboot_notifier(&cmm_reboot_nb);
 453 out_oom_notifier:
 454         unregister_oom_notifier(&cmm_oom_nb);
 455         return rc;
 456 }
 457
 458 /**
 459  * cmm_exit - Module exit
 460  *
 461  * Return value:
 462  *      nothing
 463  **/
 464 static void cmm_exit(void)
 465 {
 466         if (cmm_thread_ptr)
 467                 kthread_stop(cmm_thread_ptr);
 468         unregister_oom_notifier(&cmm_oom_nb);
 469         unregister_reboot_notifier(&cmm_reboot_nb);
 470         cmm_free_pages(loaned_pages);
 471         cmm_unregister_sysfs(&cmm_sysdev);
 472 }
 473
 474 /**
 475  * cmm_set_disable - Disable/Enable CMM
 476  *
 477  * Return value:
 478  *      0 on success / other on failure
 479  **/
 480 static int cmm_set_disable(const char *val, struct kernel_param *kp)
 481 {
 482         int disable = simple_strtoul(val, NULL, 10);
 483
 484         if (disable != 0 && disable != 1)
 485                 return -EINVAL;
 486
 487         if (disable && !cmm_disabled) {
 488                 if (cmm_thread_ptr)
 489                         kthread_stop(cmm_thread_ptr);
 490                 cmm_thread_ptr = NULL;
 491                 cmm_free_pages(loaned_pages);
 492         } else if (!disable && cmm_disabled) {
 493                 cmm_thread_ptr = kthread_run(cmm_thread, NULL, "cmmthread");
 494                 if (IS_ERR(cmm_thread_ptr))
 495                         return PTR_ERR(cmm_thread_ptr);
 496         }
 497
 498         cmm_disabled = disable;
 499         return 0;
 500 }
 501
 502 module_param_call(disable, cmm_set_disable, param_get_uint,
 503                   &cmm_disabled, S_IRUGO | S_IWUSR);
 504 MODULE_PARM_DESC(disable, "Disable CMM. Set to 1 to disable. "
 505                  "[Default=" __stringify(CMM_DISABLE) "]");
 506
 507 module_init(cmm_init);
 508 module_exit(cmm_exit);