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1a59d1b8 | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
84af458b BK |
2 | /* |
3 | * Collaborative memory management interface. | |
4 | * | |
5 | * Copyright (C) 2008 IBM Corporation | |
6 | * Author(s): Brian King (brking@linux.vnet.ibm.com), | |
84af458b BK |
7 | */ |
8 | ||
9 | #include <linux/ctype.h> | |
10 | #include <linux/delay.h> | |
11 | #include <linux/errno.h> | |
12 | #include <linux/fs.h> | |
5a0e3ad6 | 13 | #include <linux/gfp.h> |
84af458b BK |
14 | #include <linux/kthread.h> |
15 | #include <linux/module.h> | |
16 | #include <linux/oom.h> | |
fecba962 | 17 | #include <linux/reboot.h> |
84af458b BK |
18 | #include <linux/sched.h> |
19 | #include <linux/stringify.h> | |
20 | #include <linux/swap.h> | |
6c9d2909 | 21 | #include <linux/device.h> |
84af458b BK |
22 | #include <asm/firmware.h> |
23 | #include <asm/hvcall.h> | |
24 | #include <asm/mmu.h> | |
25 | #include <asm/pgalloc.h> | |
7c0f6ba6 | 26 | #include <linux/uaccess.h> |
14b8a76b | 27 | #include <linux/memory.h> |
212bebb4 | 28 | #include <asm/plpar_wrappers.h> |
84af458b | 29 | |
8f272a5d ME |
30 | #include "pseries.h" |
31 | ||
84af458b BK |
32 | #define CMM_DRIVER_VERSION "1.0.0" |
33 | #define CMM_DEFAULT_DELAY 1 | |
14b8a76b | 34 | #define CMM_HOTPLUG_DELAY 5 |
84af458b BK |
35 | #define CMM_DEBUG 0 |
36 | #define CMM_DISABLE 0 | |
37 | #define CMM_OOM_KB 1024 | |
38 | #define CMM_MIN_MEM_MB 256 | |
39 | #define KB2PAGES(_p) ((_p)>>(PAGE_SHIFT-10)) | |
40 | #define PAGES2KB(_p) ((_p)<<(PAGE_SHIFT-10)) | |
14b8a76b RJ |
41 | /* |
42 | * The priority level tries to ensure that this notifier is called as | |
43 | * late as possible to reduce thrashing in the shared memory pool. | |
44 | */ | |
45 | #define CMM_MEM_HOTPLUG_PRI 1 | |
46 | #define CMM_MEM_ISOLATE_PRI 15 | |
84af458b BK |
47 | |
48 | static unsigned int delay = CMM_DEFAULT_DELAY; | |
14b8a76b | 49 | static unsigned int hotplug_delay = CMM_HOTPLUG_DELAY; |
84af458b BK |
50 | static unsigned int oom_kb = CMM_OOM_KB; |
51 | static unsigned int cmm_debug = CMM_DEBUG; | |
52 | static unsigned int cmm_disabled = CMM_DISABLE; | |
53 | static unsigned long min_mem_mb = CMM_MIN_MEM_MB; | |
6c9d2909 | 54 | static struct device cmm_dev; |
84af458b BK |
55 | |
56 | MODULE_AUTHOR("Brian King <brking@linux.vnet.ibm.com>"); | |
57 | MODULE_DESCRIPTION("IBM System p Collaborative Memory Manager"); | |
58 | MODULE_LICENSE("GPL"); | |
59 | MODULE_VERSION(CMM_DRIVER_VERSION); | |
60 | ||
57ad583f | 61 | module_param_named(delay, delay, uint, 0644); |
84af458b BK |
62 | MODULE_PARM_DESC(delay, "Delay (in seconds) between polls to query hypervisor paging requests. " |
63 | "[Default=" __stringify(CMM_DEFAULT_DELAY) "]"); | |
57ad583f | 64 | module_param_named(hotplug_delay, hotplug_delay, uint, 0644); |
b0b5a765 | 65 | MODULE_PARM_DESC(hotplug_delay, "Delay (in seconds) after memory hotplug remove " |
14b8a76b RJ |
66 | "before loaning resumes. " |
67 | "[Default=" __stringify(CMM_HOTPLUG_DELAY) "]"); | |
57ad583f | 68 | module_param_named(oom_kb, oom_kb, uint, 0644); |
84af458b BK |
69 | MODULE_PARM_DESC(oom_kb, "Amount of memory in kb to free on OOM. " |
70 | "[Default=" __stringify(CMM_OOM_KB) "]"); | |
57ad583f | 71 | module_param_named(min_mem_mb, min_mem_mb, ulong, 0644); |
84af458b BK |
72 | MODULE_PARM_DESC(min_mem_mb, "Minimum amount of memory (in MB) to not balloon. " |
73 | "[Default=" __stringify(CMM_MIN_MEM_MB) "]"); | |
57ad583f | 74 | module_param_named(debug, cmm_debug, uint, 0644); |
84af458b BK |
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 | ||
14b8a76b RJ |
95 | static DEFINE_MUTEX(hotplug_mutex); |
96 | static int hotplug_occurred; /* protected by the hotplug mutex */ | |
97 | ||
84af458b BK |
98 | static struct task_struct *cmm_thread_ptr; |
99 | ||
8f272a5d ME |
100 | static long plpar_page_set_loaned(unsigned long vpa) |
101 | { | |
102 | unsigned long cmo_page_sz = cmo_get_page_size(); | |
103 | long rc = 0; | |
104 | int i; | |
105 | ||
106 | for (i = 0; !rc && i < PAGE_SIZE; i += cmo_page_sz) | |
107 | rc = plpar_hcall_norets(H_PAGE_INIT, H_PAGE_SET_LOANED, vpa + i, 0); | |
108 | ||
109 | for (i -= cmo_page_sz; rc && i != 0; i -= cmo_page_sz) | |
110 | plpar_hcall_norets(H_PAGE_INIT, H_PAGE_SET_ACTIVE, | |
111 | vpa + i - cmo_page_sz, 0); | |
112 | ||
113 | return rc; | |
114 | } | |
115 | ||
116 | static long plpar_page_set_active(unsigned long vpa) | |
117 | { | |
118 | unsigned long cmo_page_sz = cmo_get_page_size(); | |
119 | long rc = 0; | |
120 | int i; | |
121 | ||
122 | for (i = 0; !rc && i < PAGE_SIZE; i += cmo_page_sz) | |
123 | rc = plpar_hcall_norets(H_PAGE_INIT, H_PAGE_SET_ACTIVE, vpa + i, 0); | |
124 | ||
125 | for (i -= cmo_page_sz; rc && i != 0; i -= cmo_page_sz) | |
126 | plpar_hcall_norets(H_PAGE_INIT, H_PAGE_SET_LOANED, | |
127 | vpa + i - cmo_page_sz, 0); | |
128 | ||
129 | return rc; | |
130 | } | |
131 | ||
84af458b BK |
132 | /** |
133 | * cmm_alloc_pages - Allocate pages and mark them as loaned | |
134 | * @nr: number of pages to allocate | |
135 | * | |
136 | * Return value: | |
137 | * number of pages requested to be allocated which were not | |
138 | **/ | |
139 | static long cmm_alloc_pages(long nr) | |
140 | { | |
141 | struct cmm_page_array *pa, *npa; | |
142 | unsigned long addr; | |
143 | long rc; | |
144 | ||
145 | cmm_dbg("Begin request for %ld pages\n", nr); | |
146 | ||
147 | while (nr) { | |
14b8a76b RJ |
148 | /* Exit if a hotplug operation is in progress or occurred */ |
149 | if (mutex_trylock(&hotplug_mutex)) { | |
150 | if (hotplug_occurred) { | |
151 | mutex_unlock(&hotplug_mutex); | |
152 | break; | |
153 | } | |
154 | mutex_unlock(&hotplug_mutex); | |
155 | } else { | |
156 | break; | |
157 | } | |
158 | ||
84af458b BK |
159 | addr = __get_free_page(GFP_NOIO | __GFP_NOWARN | |
160 | __GFP_NORETRY | __GFP_NOMEMALLOC); | |
161 | if (!addr) | |
162 | break; | |
163 | spin_lock(&cmm_lock); | |
164 | pa = cmm_page_list; | |
165 | if (!pa || pa->index >= CMM_NR_PAGES) { | |
166 | /* Need a new page for the page list. */ | |
167 | spin_unlock(&cmm_lock); | |
14b8a76b RJ |
168 | npa = (struct cmm_page_array *)__get_free_page( |
169 | GFP_NOIO | __GFP_NOWARN | | |
170 | __GFP_NORETRY | __GFP_NOMEMALLOC); | |
84af458b | 171 | if (!npa) { |
5df72bf3 | 172 | pr_info("%s: Can not allocate new page list\n", __func__); |
84af458b BK |
173 | free_page(addr); |
174 | break; | |
175 | } | |
176 | spin_lock(&cmm_lock); | |
177 | pa = cmm_page_list; | |
178 | ||
179 | if (!pa || pa->index >= CMM_NR_PAGES) { | |
180 | npa->next = pa; | |
181 | npa->index = 0; | |
182 | pa = npa; | |
183 | cmm_page_list = pa; | |
184 | } else | |
185 | free_page((unsigned long) npa); | |
186 | } | |
187 | ||
188 | if ((rc = plpar_page_set_loaned(__pa(addr)))) { | |
5df72bf3 | 189 | pr_err("%s: Can not set page to loaned. rc=%ld\n", __func__, rc); |
84af458b BK |
190 | spin_unlock(&cmm_lock); |
191 | free_page(addr); | |
192 | break; | |
193 | } | |
194 | ||
195 | pa->page[pa->index++] = addr; | |
196 | loaned_pages++; | |
ca79b0c2 | 197 | totalram_pages_dec(); |
84af458b BK |
198 | spin_unlock(&cmm_lock); |
199 | nr--; | |
200 | } | |
201 | ||
202 | cmm_dbg("End request with %ld pages unfulfilled\n", nr); | |
203 | return nr; | |
204 | } | |
205 | ||
206 | /** | |
207 | * cmm_free_pages - Free pages and mark them as active | |
208 | * @nr: number of pages to free | |
209 | * | |
210 | * Return value: | |
211 | * number of pages requested to be freed which were not | |
212 | **/ | |
213 | static long cmm_free_pages(long nr) | |
214 | { | |
215 | struct cmm_page_array *pa; | |
216 | unsigned long addr; | |
217 | ||
218 | cmm_dbg("Begin free of %ld pages.\n", nr); | |
219 | spin_lock(&cmm_lock); | |
220 | pa = cmm_page_list; | |
221 | while (nr) { | |
222 | if (!pa || pa->index <= 0) | |
223 | break; | |
224 | addr = pa->page[--pa->index]; | |
225 | ||
226 | if (pa->index == 0) { | |
227 | pa = pa->next; | |
228 | free_page((unsigned long) cmm_page_list); | |
229 | cmm_page_list = pa; | |
230 | } | |
231 | ||
232 | plpar_page_set_active(__pa(addr)); | |
233 | free_page(addr); | |
234 | loaned_pages--; | |
235 | nr--; | |
ca79b0c2 | 236 | totalram_pages_inc(); |
84af458b BK |
237 | } |
238 | spin_unlock(&cmm_lock); | |
239 | cmm_dbg("End request with %ld pages unfulfilled\n", nr); | |
240 | return nr; | |
241 | } | |
242 | ||
243 | /** | |
244 | * cmm_oom_notify - OOM notifier | |
245 | * @self: notifier block struct | |
246 | * @dummy: not used | |
247 | * @parm: returned - number of pages freed | |
248 | * | |
249 | * Return value: | |
250 | * NOTIFY_OK | |
251 | **/ | |
252 | static int cmm_oom_notify(struct notifier_block *self, | |
253 | unsigned long dummy, void *parm) | |
254 | { | |
255 | unsigned long *freed = parm; | |
256 | long nr = KB2PAGES(oom_kb); | |
257 | ||
258 | cmm_dbg("OOM processing started\n"); | |
259 | nr = cmm_free_pages(nr); | |
260 | loaned_pages_target = loaned_pages; | |
261 | *freed += KB2PAGES(oom_kb) - nr; | |
262 | oom_freed_pages += KB2PAGES(oom_kb) - nr; | |
263 | cmm_dbg("OOM processing complete\n"); | |
264 | return NOTIFY_OK; | |
265 | } | |
266 | ||
267 | /** | |
268 | * cmm_get_mpp - Read memory performance parameters | |
269 | * | |
270 | * Makes hcall to query the current page loan request from the hypervisor. | |
271 | * | |
272 | * Return value: | |
273 | * nothing | |
274 | **/ | |
275 | static void cmm_get_mpp(void) | |
276 | { | |
277 | int rc; | |
278 | struct hvcall_mpp_data mpp_data; | |
8be8cf5b | 279 | signed long active_pages_target, page_loan_request, target; |
ca79b0c2 | 280 | signed long total_pages = totalram_pages() + loaned_pages; |
8be8cf5b | 281 | signed long min_mem_pages = (min_mem_mb * 1024 * 1024) / PAGE_SIZE; |
84af458b BK |
282 | |
283 | rc = h_get_mpp(&mpp_data); | |
284 | ||
285 | if (rc != H_SUCCESS) | |
286 | return; | |
287 | ||
288 | page_loan_request = div_s64((s64)mpp_data.loan_request, PAGE_SIZE); | |
8be8cf5b BK |
289 | target = page_loan_request + (signed long)loaned_pages; |
290 | ||
291 | if (target < 0 || total_pages < min_mem_pages) | |
292 | target = 0; | |
293 | ||
294 | if (target > oom_freed_pages) | |
295 | target -= oom_freed_pages; | |
84af458b | 296 | else |
8be8cf5b BK |
297 | target = 0; |
298 | ||
299 | active_pages_target = total_pages - target; | |
300 | ||
301 | if (min_mem_pages > active_pages_target) | |
302 | target = total_pages - min_mem_pages; | |
84af458b | 303 | |
8be8cf5b BK |
304 | if (target < 0) |
305 | target = 0; | |
84af458b | 306 | |
8be8cf5b | 307 | loaned_pages_target = target; |
84af458b BK |
308 | |
309 | cmm_dbg("delta = %ld, loaned = %lu, target = %lu, oom = %lu, totalram = %lu\n", | |
310 | page_loan_request, loaned_pages, loaned_pages_target, | |
ca79b0c2 | 311 | oom_freed_pages, totalram_pages()); |
84af458b BK |
312 | } |
313 | ||
314 | static struct notifier_block cmm_oom_nb = { | |
315 | .notifier_call = cmm_oom_notify | |
316 | }; | |
317 | ||
318 | /** | |
319 | * cmm_thread - CMM task thread | |
320 | * @dummy: not used | |
321 | * | |
322 | * Return value: | |
323 | * 0 | |
324 | **/ | |
325 | static int cmm_thread(void *dummy) | |
326 | { | |
327 | unsigned long timeleft; | |
328 | ||
329 | while (1) { | |
330 | timeleft = msleep_interruptible(delay * 1000); | |
331 | ||
14b8a76b | 332 | if (kthread_should_stop() || timeleft) |
84af458b | 333 | break; |
14b8a76b RJ |
334 | |
335 | if (mutex_trylock(&hotplug_mutex)) { | |
336 | if (hotplug_occurred) { | |
337 | hotplug_occurred = 0; | |
338 | mutex_unlock(&hotplug_mutex); | |
339 | cmm_dbg("Hotplug operation has occurred, " | |
340 | "loaning activity suspended " | |
341 | "for %d seconds.\n", | |
342 | hotplug_delay); | |
343 | timeleft = msleep_interruptible(hotplug_delay * | |
344 | 1000); | |
345 | if (kthread_should_stop() || timeleft) | |
346 | break; | |
347 | continue; | |
348 | } | |
349 | mutex_unlock(&hotplug_mutex); | |
350 | } else { | |
351 | cmm_dbg("Hotplug operation in progress, activity " | |
352 | "suspended\n"); | |
353 | continue; | |
84af458b BK |
354 | } |
355 | ||
356 | cmm_get_mpp(); | |
357 | ||
358 | if (loaned_pages_target > loaned_pages) { | |
359 | if (cmm_alloc_pages(loaned_pages_target - loaned_pages)) | |
360 | loaned_pages_target = loaned_pages; | |
361 | } else if (loaned_pages_target < loaned_pages) | |
362 | cmm_free_pages(loaned_pages - loaned_pages_target); | |
363 | } | |
364 | return 0; | |
365 | } | |
366 | ||
367 | #define CMM_SHOW(name, format, args...) \ | |
6c9d2909 KS |
368 | static ssize_t show_##name(struct device *dev, \ |
369 | struct device_attribute *attr, \ | |
3cee67f7 | 370 | char *buf) \ |
84af458b BK |
371 | { \ |
372 | return sprintf(buf, format, ##args); \ | |
373 | } \ | |
57ad583f | 374 | static DEVICE_ATTR(name, 0444, show_##name, NULL) |
84af458b BK |
375 | |
376 | CMM_SHOW(loaned_kb, "%lu\n", PAGES2KB(loaned_pages)); | |
377 | CMM_SHOW(loaned_target_kb, "%lu\n", PAGES2KB(loaned_pages_target)); | |
378 | ||
6c9d2909 KS |
379 | static ssize_t show_oom_pages(struct device *dev, |
380 | struct device_attribute *attr, char *buf) | |
84af458b BK |
381 | { |
382 | return sprintf(buf, "%lu\n", PAGES2KB(oom_freed_pages)); | |
383 | } | |
384 | ||
6c9d2909 KS |
385 | static ssize_t store_oom_pages(struct device *dev, |
386 | struct device_attribute *attr, | |
84af458b BK |
387 | const char *buf, size_t count) |
388 | { | |
389 | unsigned long val = simple_strtoul (buf, NULL, 10); | |
390 | ||
391 | if (!capable(CAP_SYS_ADMIN)) | |
392 | return -EPERM; | |
393 | if (val != 0) | |
394 | return -EBADMSG; | |
395 | ||
396 | oom_freed_pages = 0; | |
397 | return count; | |
398 | } | |
399 | ||
57ad583f | 400 | static DEVICE_ATTR(oom_freed_kb, 0644, |
84af458b BK |
401 | show_oom_pages, store_oom_pages); |
402 | ||
6c9d2909 KS |
403 | static struct device_attribute *cmm_attrs[] = { |
404 | &dev_attr_loaned_kb, | |
405 | &dev_attr_loaned_target_kb, | |
406 | &dev_attr_oom_freed_kb, | |
84af458b BK |
407 | }; |
408 | ||
6c9d2909 | 409 | static struct bus_type cmm_subsys = { |
84af458b | 410 | .name = "cmm", |
6c9d2909 | 411 | .dev_name = "cmm", |
84af458b BK |
412 | }; |
413 | ||
6182db06 DH |
414 | static void cmm_release_device(struct device *dev) |
415 | { | |
416 | } | |
417 | ||
84af458b BK |
418 | /** |
419 | * cmm_sysfs_register - Register with sysfs | |
420 | * | |
421 | * Return value: | |
422 | * 0 on success / other on failure | |
423 | **/ | |
6c9d2909 | 424 | static int cmm_sysfs_register(struct device *dev) |
84af458b BK |
425 | { |
426 | int i, rc; | |
427 | ||
6c9d2909 | 428 | if ((rc = subsys_system_register(&cmm_subsys, NULL))) |
84af458b BK |
429 | return rc; |
430 | ||
6c9d2909 KS |
431 | dev->id = 0; |
432 | dev->bus = &cmm_subsys; | |
6182db06 | 433 | dev->release = cmm_release_device; |
84af458b | 434 | |
6c9d2909 KS |
435 | if ((rc = device_register(dev))) |
436 | goto subsys_unregister; | |
84af458b BK |
437 | |
438 | for (i = 0; i < ARRAY_SIZE(cmm_attrs); i++) { | |
6c9d2909 | 439 | if ((rc = device_create_file(dev, cmm_attrs[i]))) |
84af458b BK |
440 | goto fail; |
441 | } | |
442 | ||
443 | return 0; | |
444 | ||
445 | fail: | |
446 | while (--i >= 0) | |
6c9d2909 KS |
447 | device_remove_file(dev, cmm_attrs[i]); |
448 | device_unregister(dev); | |
449 | subsys_unregister: | |
450 | bus_unregister(&cmm_subsys); | |
84af458b BK |
451 | return rc; |
452 | } | |
453 | ||
454 | /** | |
455 | * cmm_unregister_sysfs - Unregister from sysfs | |
456 | * | |
457 | **/ | |
6c9d2909 | 458 | static void cmm_unregister_sysfs(struct device *dev) |
84af458b BK |
459 | { |
460 | int i; | |
461 | ||
462 | for (i = 0; i < ARRAY_SIZE(cmm_attrs); i++) | |
6c9d2909 KS |
463 | device_remove_file(dev, cmm_attrs[i]); |
464 | device_unregister(dev); | |
465 | bus_unregister(&cmm_subsys); | |
84af458b BK |
466 | } |
467 | ||
fecba962 BK |
468 | /** |
469 | * cmm_reboot_notifier - Make sure pages are not still marked as "loaned" | |
470 | * | |
471 | **/ | |
472 | static int cmm_reboot_notifier(struct notifier_block *nb, | |
473 | unsigned long action, void *unused) | |
474 | { | |
475 | if (action == SYS_RESTART) { | |
476 | if (cmm_thread_ptr) | |
477 | kthread_stop(cmm_thread_ptr); | |
478 | cmm_thread_ptr = NULL; | |
479 | cmm_free_pages(loaned_pages); | |
480 | } | |
481 | return NOTIFY_DONE; | |
482 | } | |
483 | ||
484 | static struct notifier_block cmm_reboot_nb = { | |
485 | .notifier_call = cmm_reboot_notifier, | |
486 | }; | |
487 | ||
14b8a76b RJ |
488 | /** |
489 | * cmm_count_pages - Count the number of pages loaned in a particular range. | |
490 | * | |
491 | * @arg: memory_isolate_notify structure with address range and count | |
492 | * | |
493 | * Return value: | |
494 | * 0 on success | |
495 | **/ | |
496 | static unsigned long cmm_count_pages(void *arg) | |
497 | { | |
498 | struct memory_isolate_notify *marg = arg; | |
499 | struct cmm_page_array *pa; | |
500 | unsigned long start = (unsigned long)pfn_to_kaddr(marg->start_pfn); | |
501 | unsigned long end = start + (marg->nr_pages << PAGE_SHIFT); | |
502 | unsigned long idx; | |
503 | ||
504 | spin_lock(&cmm_lock); | |
505 | pa = cmm_page_list; | |
506 | while (pa) { | |
507 | if ((unsigned long)pa >= start && (unsigned long)pa < end) | |
508 | marg->pages_found++; | |
509 | for (idx = 0; idx < pa->index; idx++) | |
510 | if (pa->page[idx] >= start && pa->page[idx] < end) | |
511 | marg->pages_found++; | |
512 | pa = pa->next; | |
513 | } | |
514 | spin_unlock(&cmm_lock); | |
515 | return 0; | |
516 | } | |
517 | ||
518 | /** | |
519 | * cmm_memory_isolate_cb - Handle memory isolation notifier calls | |
520 | * @self: notifier block struct | |
521 | * @action: action to take | |
522 | * @arg: struct memory_isolate_notify data for handler | |
523 | * | |
524 | * Return value: | |
525 | * NOTIFY_OK or notifier error based on subfunction return value | |
526 | **/ | |
527 | static int cmm_memory_isolate_cb(struct notifier_block *self, | |
528 | unsigned long action, void *arg) | |
529 | { | |
530 | int ret = 0; | |
531 | ||
532 | if (action == MEM_ISOLATE_COUNT) | |
533 | ret = cmm_count_pages(arg); | |
534 | ||
7e26065d | 535 | return notifier_from_errno(ret); |
14b8a76b RJ |
536 | } |
537 | ||
538 | static struct notifier_block cmm_mem_isolate_nb = { | |
539 | .notifier_call = cmm_memory_isolate_cb, | |
540 | .priority = CMM_MEM_ISOLATE_PRI | |
541 | }; | |
542 | ||
543 | /** | |
544 | * cmm_mem_going_offline - Unloan pages where memory is to be removed | |
545 | * @arg: memory_notify structure with page range to be offlined | |
546 | * | |
547 | * Return value: | |
548 | * 0 on success | |
549 | **/ | |
550 | static int cmm_mem_going_offline(void *arg) | |
551 | { | |
552 | struct memory_notify *marg = arg; | |
553 | unsigned long start_page = (unsigned long)pfn_to_kaddr(marg->start_pfn); | |
554 | unsigned long end_page = start_page + (marg->nr_pages << PAGE_SHIFT); | |
555 | struct cmm_page_array *pa_curr, *pa_last, *npa; | |
556 | unsigned long idx; | |
557 | unsigned long freed = 0; | |
558 | ||
559 | cmm_dbg("Memory going offline, searching 0x%lx (%ld pages).\n", | |
560 | start_page, marg->nr_pages); | |
561 | spin_lock(&cmm_lock); | |
562 | ||
563 | /* Search the page list for pages in the range to be offlined */ | |
564 | pa_last = pa_curr = cmm_page_list; | |
565 | while (pa_curr) { | |
566 | for (idx = (pa_curr->index - 1); (idx + 1) > 0; idx--) { | |
567 | if ((pa_curr->page[idx] < start_page) || | |
568 | (pa_curr->page[idx] >= end_page)) | |
569 | continue; | |
570 | ||
571 | plpar_page_set_active(__pa(pa_curr->page[idx])); | |
572 | free_page(pa_curr->page[idx]); | |
573 | freed++; | |
574 | loaned_pages--; | |
ca79b0c2 | 575 | totalram_pages_inc(); |
14b8a76b RJ |
576 | pa_curr->page[idx] = pa_last->page[--pa_last->index]; |
577 | if (pa_last->index == 0) { | |
578 | if (pa_curr == pa_last) | |
579 | pa_curr = pa_last->next; | |
580 | pa_last = pa_last->next; | |
581 | free_page((unsigned long)cmm_page_list); | |
582 | cmm_page_list = pa_last; | |
14b8a76b RJ |
583 | } |
584 | } | |
585 | pa_curr = pa_curr->next; | |
586 | } | |
587 | ||
588 | /* Search for page list structures in the range to be offlined */ | |
589 | pa_last = NULL; | |
590 | pa_curr = cmm_page_list; | |
591 | while (pa_curr) { | |
592 | if (((unsigned long)pa_curr >= start_page) && | |
593 | ((unsigned long)pa_curr < end_page)) { | |
594 | npa = (struct cmm_page_array *)__get_free_page( | |
595 | GFP_NOIO | __GFP_NOWARN | | |
596 | __GFP_NORETRY | __GFP_NOMEMALLOC); | |
597 | if (!npa) { | |
598 | spin_unlock(&cmm_lock); | |
599 | cmm_dbg("Failed to allocate memory for list " | |
600 | "management. Memory hotplug " | |
601 | "failed.\n"); | |
e2be2371 | 602 | return -ENOMEM; |
14b8a76b RJ |
603 | } |
604 | memcpy(npa, pa_curr, PAGE_SIZE); | |
605 | if (pa_curr == cmm_page_list) | |
606 | cmm_page_list = npa; | |
607 | if (pa_last) | |
608 | pa_last->next = npa; | |
609 | free_page((unsigned long) pa_curr); | |
610 | freed++; | |
611 | pa_curr = npa; | |
612 | } | |
613 | ||
614 | pa_last = pa_curr; | |
615 | pa_curr = pa_curr->next; | |
616 | } | |
617 | ||
618 | spin_unlock(&cmm_lock); | |
619 | cmm_dbg("Released %ld pages in the search range.\n", freed); | |
620 | ||
621 | return 0; | |
622 | } | |
623 | ||
624 | /** | |
625 | * cmm_memory_cb - Handle memory hotplug notifier calls | |
626 | * @self: notifier block struct | |
627 | * @action: action to take | |
628 | * @arg: struct memory_notify data for handler | |
629 | * | |
630 | * Return value: | |
631 | * NOTIFY_OK or notifier error based on subfunction return value | |
632 | * | |
633 | **/ | |
634 | static int cmm_memory_cb(struct notifier_block *self, | |
635 | unsigned long action, void *arg) | |
636 | { | |
637 | int ret = 0; | |
638 | ||
639 | switch (action) { | |
640 | case MEM_GOING_OFFLINE: | |
641 | mutex_lock(&hotplug_mutex); | |
642 | hotplug_occurred = 1; | |
643 | ret = cmm_mem_going_offline(arg); | |
644 | break; | |
645 | case MEM_OFFLINE: | |
646 | case MEM_CANCEL_OFFLINE: | |
647 | mutex_unlock(&hotplug_mutex); | |
648 | cmm_dbg("Memory offline operation complete.\n"); | |
649 | break; | |
650 | case MEM_GOING_ONLINE: | |
651 | case MEM_ONLINE: | |
652 | case MEM_CANCEL_ONLINE: | |
653 | break; | |
654 | } | |
655 | ||
7e26065d | 656 | return notifier_from_errno(ret); |
14b8a76b RJ |
657 | } |
658 | ||
659 | static struct notifier_block cmm_mem_nb = { | |
660 | .notifier_call = cmm_memory_cb, | |
661 | .priority = CMM_MEM_HOTPLUG_PRI | |
662 | }; | |
663 | ||
84af458b BK |
664 | /** |
665 | * cmm_init - Module initialization | |
666 | * | |
667 | * Return value: | |
668 | * 0 on success / other on failure | |
669 | **/ | |
670 | static int cmm_init(void) | |
671 | { | |
672 | int rc = -ENOMEM; | |
673 | ||
674 | if (!firmware_has_feature(FW_FEATURE_CMO)) | |
675 | return -EOPNOTSUPP; | |
676 | ||
677 | if ((rc = register_oom_notifier(&cmm_oom_nb)) < 0) | |
678 | return rc; | |
679 | ||
fecba962 | 680 | if ((rc = register_reboot_notifier(&cmm_reboot_nb))) |
84af458b BK |
681 | goto out_oom_notifier; |
682 | ||
6c9d2909 | 683 | if ((rc = cmm_sysfs_register(&cmm_dev))) |
fecba962 BK |
684 | goto out_reboot_notifier; |
685 | ||
14b8a76b RJ |
686 | if (register_memory_notifier(&cmm_mem_nb) || |
687 | register_memory_isolate_notifier(&cmm_mem_isolate_nb)) | |
688 | goto out_unregister_notifier; | |
689 | ||
84af458b BK |
690 | if (cmm_disabled) |
691 | return rc; | |
692 | ||
693 | cmm_thread_ptr = kthread_run(cmm_thread, NULL, "cmmthread"); | |
694 | if (IS_ERR(cmm_thread_ptr)) { | |
695 | rc = PTR_ERR(cmm_thread_ptr); | |
14b8a76b | 696 | goto out_unregister_notifier; |
84af458b BK |
697 | } |
698 | ||
699 | return rc; | |
700 | ||
14b8a76b RJ |
701 | out_unregister_notifier: |
702 | unregister_memory_notifier(&cmm_mem_nb); | |
703 | unregister_memory_isolate_notifier(&cmm_mem_isolate_nb); | |
6c9d2909 | 704 | cmm_unregister_sysfs(&cmm_dev); |
fecba962 BK |
705 | out_reboot_notifier: |
706 | unregister_reboot_notifier(&cmm_reboot_nb); | |
84af458b BK |
707 | out_oom_notifier: |
708 | unregister_oom_notifier(&cmm_oom_nb); | |
709 | return rc; | |
710 | } | |
711 | ||
712 | /** | |
713 | * cmm_exit - Module exit | |
714 | * | |
715 | * Return value: | |
716 | * nothing | |
717 | **/ | |
718 | static void cmm_exit(void) | |
719 | { | |
720 | if (cmm_thread_ptr) | |
721 | kthread_stop(cmm_thread_ptr); | |
722 | unregister_oom_notifier(&cmm_oom_nb); | |
fecba962 | 723 | unregister_reboot_notifier(&cmm_reboot_nb); |
14b8a76b RJ |
724 | unregister_memory_notifier(&cmm_mem_nb); |
725 | unregister_memory_isolate_notifier(&cmm_mem_isolate_nb); | |
84af458b | 726 | cmm_free_pages(loaned_pages); |
6c9d2909 | 727 | cmm_unregister_sysfs(&cmm_dev); |
84af458b BK |
728 | } |
729 | ||
730 | /** | |
731 | * cmm_set_disable - Disable/Enable CMM | |
732 | * | |
733 | * Return value: | |
734 | * 0 on success / other on failure | |
735 | **/ | |
e4dca7b7 | 736 | static int cmm_set_disable(const char *val, const struct kernel_param *kp) |
84af458b BK |
737 | { |
738 | int disable = simple_strtoul(val, NULL, 10); | |
739 | ||
740 | if (disable != 0 && disable != 1) | |
741 | return -EINVAL; | |
742 | ||
743 | if (disable && !cmm_disabled) { | |
744 | if (cmm_thread_ptr) | |
745 | kthread_stop(cmm_thread_ptr); | |
746 | cmm_thread_ptr = NULL; | |
747 | cmm_free_pages(loaned_pages); | |
748 | } else if (!disable && cmm_disabled) { | |
749 | cmm_thread_ptr = kthread_run(cmm_thread, NULL, "cmmthread"); | |
750 | if (IS_ERR(cmm_thread_ptr)) | |
751 | return PTR_ERR(cmm_thread_ptr); | |
752 | } | |
753 | ||
754 | cmm_disabled = disable; | |
755 | return 0; | |
756 | } | |
757 | ||
758 | module_param_call(disable, cmm_set_disable, param_get_uint, | |
57ad583f | 759 | &cmm_disabled, 0644); |
84af458b BK |
760 | MODULE_PARM_DESC(disable, "Disable CMM. Set to 1 to disable. " |
761 | "[Default=" __stringify(CMM_DISABLE) "]"); | |
762 | ||
763 | module_init(cmm_init); | |
764 | module_exit(cmm_exit); |