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   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         unsigned long active_pages_target;
 233         signed long page_loan_request;
 234
 235         rc = h_get_mpp(&mpp_data);
 236
 237         if (rc != H_SUCCESS)
 238                 return;
 239
 240         page_loan_request = div_s64((s64)mpp_data.loan_request, PAGE_SIZE);
 241         loaned_pages_target = page_loan_request + loaned_pages;
 242         if (loaned_pages_target > oom_freed_pages)
 243                 loaned_pages_target -= oom_freed_pages;
 244         else
 245                 loaned_pages_target = 0;
 246
 247         active_pages_target = totalram_pages + loaned_pages - loaned_pages_target;
 248
 249         if ((min_mem_mb * 1024 * 1024) > (active_pages_target * PAGE_SIZE))
 250                 loaned_pages_target = totalram_pages + loaned_pages -
 251                         ((min_mem_mb * 1024 * 1024) / PAGE_SIZE);
 252
 253         cmm_dbg("delta = %ld, loaned = %lu, target = %lu, oom = %lu, totalram = %lu\n",
 254                 page_loan_request, loaned_pages, loaned_pages_target,
 255                 oom_freed_pages, totalram_pages);
 256 }
 257
 258 static struct notifier_block cmm_oom_nb = {
 259         .notifier_call = cmm_oom_notify
 260 };
 261
 262 /**
 263  * cmm_thread - CMM task thread
 264  * @dummy:      not used
 265  *
 266  * Return value:
 267  *      0
 268  **/
 269 static int cmm_thread(void *dummy)
 270 {
 271         unsigned long timeleft;
 272
 273         while (1) {
 274                 timeleft = msleep_interruptible(delay * 1000);
 275
 276                 if (kthread_should_stop() || timeleft) {
 277                         loaned_pages_target = loaned_pages;
 278                         break;
 279                 }
 280
 281                 cmm_get_mpp();
 282
 283                 if (loaned_pages_target > loaned_pages) {
 284                         if (cmm_alloc_pages(loaned_pages_target - loaned_pages))
 285                                 loaned_pages_target = loaned_pages;
 286                 } else if (loaned_pages_target < loaned_pages)
 287                         cmm_free_pages(loaned_pages - loaned_pages_target);
 288         }
 289         return 0;
 290 }
 291
 292 #define CMM_SHOW(name, format, args...)                 \
 293         static ssize_t show_##name(struct sys_device *dev,      \
 294                                    struct sysdev_attribute *attr,       \
 295                                    char *buf)                   \
 296         {                                                       \
 297                 return sprintf(buf, format, ##args);            \
 298         }                                                       \
 299         static SYSDEV_ATTR(name, S_IRUGO, show_##name, NULL)
 300
 301 CMM_SHOW(loaned_kb, "%lu\n", PAGES2KB(loaned_pages));
 302 CMM_SHOW(loaned_target_kb, "%lu\n", PAGES2KB(loaned_pages_target));
 303
 304 static ssize_t show_oom_pages(struct sys_device *dev,
 305                               struct sysdev_attribute *attr, char *buf)
 306 {
 307         return sprintf(buf, "%lu\n", PAGES2KB(oom_freed_pages));
 308 }
 309
 310 static ssize_t store_oom_pages(struct sys_device *dev,
 311                                struct sysdev_attribute *attr,
 312                                const char *buf, size_t count)
 313 {
 314         unsigned long val = simple_strtoul (buf, NULL, 10);
 315
 316         if (!capable(CAP_SYS_ADMIN))
 317                 return -EPERM;
 318         if (val != 0)
 319                 return -EBADMSG;
 320
 321         oom_freed_pages = 0;
 322         return count;
 323 }
 324
 325 static SYSDEV_ATTR(oom_freed_kb, S_IWUSR| S_IRUGO,
 326                    show_oom_pages, store_oom_pages);
 327
 328 static struct sysdev_attribute *cmm_attrs[] = {
 329         &attr_loaned_kb,
 330         &attr_loaned_target_kb,
 331         &attr_oom_freed_kb,
 332 };
 333
 334 static struct sysdev_class cmm_sysdev_class = {
 335         .name = "cmm",
 336 };
 337
 338 /**
 339  * cmm_sysfs_register - Register with sysfs
 340  *
 341  * Return value:
 342  *      0 on success / other on failure
 343  **/
 344 static int cmm_sysfs_register(struct sys_device *sysdev)
 345 {
 346         int i, rc;
 347
 348         if ((rc = sysdev_class_register(&cmm_sysdev_class)))
 349                 return rc;
 350
 351         sysdev->id = 0;
 352         sysdev->cls = &cmm_sysdev_class;
 353
 354         if ((rc = sysdev_register(sysdev)))
 355                 goto class_unregister;
 356
 357         for (i = 0; i < ARRAY_SIZE(cmm_attrs); i++) {
 358                 if ((rc = sysdev_create_file(sysdev, cmm_attrs[i])))
 359                         goto fail;
 360         }
 361
 362         return 0;
 363
 364 fail:
 365         while (--i >= 0)
 366                 sysdev_remove_file(sysdev, cmm_attrs[i]);
 367         sysdev_unregister(sysdev);
 368 class_unregister:
 369         sysdev_class_unregister(&cmm_sysdev_class);
 370         return rc;
 371 }
 372
 373 /**
 374  * cmm_unregister_sysfs - Unregister from sysfs
 375  *
 376  **/
 377 static void cmm_unregister_sysfs(struct sys_device *sysdev)
 378 {
 379         int i;
 380
 381         for (i = 0; i < ARRAY_SIZE(cmm_attrs); i++)
 382                 sysdev_remove_file(sysdev, cmm_attrs[i]);
 383         sysdev_unregister(sysdev);
 384         sysdev_class_unregister(&cmm_sysdev_class);
 385 }
 386
 387 /**
 388  * cmm_reboot_notifier - Make sure pages are not still marked as "loaned"
 389  *
 390  **/
 391 static int cmm_reboot_notifier(struct notifier_block *nb,
 392                                unsigned long action, void *unused)
 393 {
 394         if (action == SYS_RESTART) {
 395                 if (cmm_thread_ptr)
 396                         kthread_stop(cmm_thread_ptr);
 397                 cmm_thread_ptr = NULL;
 398                 cmm_free_pages(loaned_pages);
 399         }
 400         return NOTIFY_DONE;
 401 }
 402
 403 static struct notifier_block cmm_reboot_nb = {
 404         .notifier_call = cmm_reboot_notifier,
 405 };
 406
 407 /**
 408  * cmm_init - Module initialization
 409  *
 410  * Return value:
 411  *      0 on success / other on failure
 412  **/
 413 static int cmm_init(void)
 414 {
 415         int rc = -ENOMEM;
 416
 417         if (!firmware_has_feature(FW_FEATURE_CMO))
 418                 return -EOPNOTSUPP;
 419
 420         if ((rc = register_oom_notifier(&cmm_oom_nb)) < 0)
 421                 return rc;
 422
 423         if ((rc = register_reboot_notifier(&cmm_reboot_nb)))
 424                 goto out_oom_notifier;
 425
 426         if ((rc = cmm_sysfs_register(&cmm_sysdev)))
 427                 goto out_reboot_notifier;
 428
 429         if (cmm_disabled)
 430                 return rc;
 431
 432         cmm_thread_ptr = kthread_run(cmm_thread, NULL, "cmmthread");
 433         if (IS_ERR(cmm_thread_ptr)) {
 434                 rc = PTR_ERR(cmm_thread_ptr);
 435                 goto out_unregister_sysfs;
 436         }
 437
 438         return rc;
 439
 440 out_unregister_sysfs:
 441         cmm_unregister_sysfs(&cmm_sysdev);
 442 out_reboot_notifier:
 443         unregister_reboot_notifier(&cmm_reboot_nb);
 444 out_oom_notifier:
 445         unregister_oom_notifier(&cmm_oom_nb);
 446         return rc;
 447 }
 448
 449 /**
 450  * cmm_exit - Module exit
 451  *
 452  * Return value:
 453  *      nothing
 454  **/
 455 static void cmm_exit(void)
 456 {
 457         if (cmm_thread_ptr)
 458                 kthread_stop(cmm_thread_ptr);
 459         unregister_oom_notifier(&cmm_oom_nb);
 460         unregister_reboot_notifier(&cmm_reboot_nb);
 461         cmm_free_pages(loaned_pages);
 462         cmm_unregister_sysfs(&cmm_sysdev);
 463 }
 464
 465 /**
 466  * cmm_set_disable - Disable/Enable CMM
 467  *
 468  * Return value:
 469  *      0 on success / other on failure
 470  **/
 471 static int cmm_set_disable(const char *val, struct kernel_param *kp)
 472 {
 473         int disable = simple_strtoul(val, NULL, 10);
 474
 475         if (disable != 0 && disable != 1)
 476                 return -EINVAL;
 477
 478         if (disable && !cmm_disabled) {
 479                 if (cmm_thread_ptr)
 480                         kthread_stop(cmm_thread_ptr);
 481                 cmm_thread_ptr = NULL;
 482                 cmm_free_pages(loaned_pages);
 483         } else if (!disable && cmm_disabled) {
 484                 cmm_thread_ptr = kthread_run(cmm_thread, NULL, "cmmthread");
 485                 if (IS_ERR(cmm_thread_ptr))
 486                         return PTR_ERR(cmm_thread_ptr);
 487         }
 488
 489         cmm_disabled = disable;
 490         return 0;
 491 }
 492
 493 module_param_call(disable, cmm_set_disable, param_get_uint,
 494                   &cmm_disabled, S_IRUGO | S_IWUSR);
 495 MODULE_PARM_DESC(disable, "Disable CMM. Set to 1 to disable. "
 496                  "[Default=" __stringify(CMM_DISABLE) "]");
 497
 498 module_init(cmm_init);
 499 module_exit(cmm_exit);