Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/teigland/dlm
[linux-2.6] / 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         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);