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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/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", __func__);
 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", __func__, 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...)                 \
 292         static ssize_t show_##name(struct sys_device *dev,      \
 293                                    struct sysdev_attribute *attr,       \
 294                                    char *buf)                   \
 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
 303 static ssize_t show_oom_pages(struct sys_device *dev,
 304                               struct sysdev_attribute *attr, char *buf)
 305 {
 306         return sprintf(buf, "%lu\n", PAGES2KB(oom_freed_pages));
 307 }
 308
 309 static ssize_t store_oom_pages(struct sys_device *dev,
 310                                struct sysdev_attribute *attr,
 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);