Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris...
[linux/fpc-iii.git] / arch / powerpc / platforms / pseries / cmm.c
blob2d8bf15879fdd3e14da6c8c46f6bbeaf7ab3f138
1 /*
2 * Collaborative memory management interface.
4 * Copyright (C) 2008 IBM Corporation
5 * Author(s): Brian King (brking@linux.vnet.ibm.com),
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.
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.
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
23 #include <linux/ctype.h>
24 #include <linux/delay.h>
25 #include <linux/errno.h>
26 #include <linux/fs.h>
27 #include <linux/gfp.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/device.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 #include <linux/memory.h>
42 #include <asm/plpar_wrappers.h>
44 #define CMM_DRIVER_VERSION "1.0.0"
45 #define CMM_DEFAULT_DELAY 1
46 #define CMM_HOTPLUG_DELAY 5
47 #define CMM_DEBUG 0
48 #define CMM_DISABLE 0
49 #define CMM_OOM_KB 1024
50 #define CMM_MIN_MEM_MB 256
51 #define KB2PAGES(_p) ((_p)>>(PAGE_SHIFT-10))
52 #define PAGES2KB(_p) ((_p)<<(PAGE_SHIFT-10))
54 * The priority level tries to ensure that this notifier is called as
55 * late as possible to reduce thrashing in the shared memory pool.
57 #define CMM_MEM_HOTPLUG_PRI 1
58 #define CMM_MEM_ISOLATE_PRI 15
60 static unsigned int delay = CMM_DEFAULT_DELAY;
61 static unsigned int hotplug_delay = CMM_HOTPLUG_DELAY;
62 static unsigned int oom_kb = CMM_OOM_KB;
63 static unsigned int cmm_debug = CMM_DEBUG;
64 static unsigned int cmm_disabled = CMM_DISABLE;
65 static unsigned long min_mem_mb = CMM_MIN_MEM_MB;
66 static struct device cmm_dev;
68 MODULE_AUTHOR("Brian King <brking@linux.vnet.ibm.com>");
69 MODULE_DESCRIPTION("IBM System p Collaborative Memory Manager");
70 MODULE_LICENSE("GPL");
71 MODULE_VERSION(CMM_DRIVER_VERSION);
73 module_param_named(delay, delay, uint, S_IRUGO | S_IWUSR);
74 MODULE_PARM_DESC(delay, "Delay (in seconds) between polls to query hypervisor paging requests. "
75 "[Default=" __stringify(CMM_DEFAULT_DELAY) "]");
76 module_param_named(hotplug_delay, hotplug_delay, uint, S_IRUGO | S_IWUSR);
77 MODULE_PARM_DESC(delay, "Delay (in seconds) after memory hotplug remove "
78 "before loaning resumes. "
79 "[Default=" __stringify(CMM_HOTPLUG_DELAY) "]");
80 module_param_named(oom_kb, oom_kb, uint, S_IRUGO | S_IWUSR);
81 MODULE_PARM_DESC(oom_kb, "Amount of memory in kb to free on OOM. "
82 "[Default=" __stringify(CMM_OOM_KB) "]");
83 module_param_named(min_mem_mb, min_mem_mb, ulong, S_IRUGO | S_IWUSR);
84 MODULE_PARM_DESC(min_mem_mb, "Minimum amount of memory (in MB) to not balloon. "
85 "[Default=" __stringify(CMM_MIN_MEM_MB) "]");
86 module_param_named(debug, cmm_debug, uint, S_IRUGO | S_IWUSR);
87 MODULE_PARM_DESC(debug, "Enable module debugging logging. Set to 1 to enable. "
88 "[Default=" __stringify(CMM_DEBUG) "]");
90 #define CMM_NR_PAGES ((PAGE_SIZE - sizeof(void *) - sizeof(unsigned long)) / sizeof(unsigned long))
92 #define cmm_dbg(...) if (cmm_debug) { printk(KERN_INFO "cmm: "__VA_ARGS__); }
94 struct cmm_page_array {
95 struct cmm_page_array *next;
96 unsigned long index;
97 unsigned long page[CMM_NR_PAGES];
100 static unsigned long loaned_pages;
101 static unsigned long loaned_pages_target;
102 static unsigned long oom_freed_pages;
104 static struct cmm_page_array *cmm_page_list;
105 static DEFINE_SPINLOCK(cmm_lock);
107 static DEFINE_MUTEX(hotplug_mutex);
108 static int hotplug_occurred; /* protected by the hotplug mutex */
110 static struct task_struct *cmm_thread_ptr;
113 * cmm_alloc_pages - Allocate pages and mark them as loaned
114 * @nr: number of pages to allocate
116 * Return value:
117 * number of pages requested to be allocated which were not
119 static long cmm_alloc_pages(long nr)
121 struct cmm_page_array *pa, *npa;
122 unsigned long addr;
123 long rc;
125 cmm_dbg("Begin request for %ld pages\n", nr);
127 while (nr) {
128 /* Exit if a hotplug operation is in progress or occurred */
129 if (mutex_trylock(&hotplug_mutex)) {
130 if (hotplug_occurred) {
131 mutex_unlock(&hotplug_mutex);
132 break;
134 mutex_unlock(&hotplug_mutex);
135 } else {
136 break;
139 addr = __get_free_page(GFP_NOIO | __GFP_NOWARN |
140 __GFP_NORETRY | __GFP_NOMEMALLOC);
141 if (!addr)
142 break;
143 spin_lock(&cmm_lock);
144 pa = cmm_page_list;
145 if (!pa || pa->index >= CMM_NR_PAGES) {
146 /* Need a new page for the page list. */
147 spin_unlock(&cmm_lock);
148 npa = (struct cmm_page_array *)__get_free_page(
149 GFP_NOIO | __GFP_NOWARN |
150 __GFP_NORETRY | __GFP_NOMEMALLOC);
151 if (!npa) {
152 pr_info("%s: Can not allocate new page list\n", __func__);
153 free_page(addr);
154 break;
156 spin_lock(&cmm_lock);
157 pa = cmm_page_list;
159 if (!pa || pa->index >= CMM_NR_PAGES) {
160 npa->next = pa;
161 npa->index = 0;
162 pa = npa;
163 cmm_page_list = pa;
164 } else
165 free_page((unsigned long) npa);
168 if ((rc = plpar_page_set_loaned(__pa(addr)))) {
169 pr_err("%s: Can not set page to loaned. rc=%ld\n", __func__, rc);
170 spin_unlock(&cmm_lock);
171 free_page(addr);
172 break;
175 pa->page[pa->index++] = addr;
176 loaned_pages++;
177 totalram_pages--;
178 spin_unlock(&cmm_lock);
179 nr--;
182 cmm_dbg("End request with %ld pages unfulfilled\n", nr);
183 return nr;
187 * cmm_free_pages - Free pages and mark them as active
188 * @nr: number of pages to free
190 * Return value:
191 * number of pages requested to be freed which were not
193 static long cmm_free_pages(long nr)
195 struct cmm_page_array *pa;
196 unsigned long addr;
198 cmm_dbg("Begin free of %ld pages.\n", nr);
199 spin_lock(&cmm_lock);
200 pa = cmm_page_list;
201 while (nr) {
202 if (!pa || pa->index <= 0)
203 break;
204 addr = pa->page[--pa->index];
206 if (pa->index == 0) {
207 pa = pa->next;
208 free_page((unsigned long) cmm_page_list);
209 cmm_page_list = pa;
212 plpar_page_set_active(__pa(addr));
213 free_page(addr);
214 loaned_pages--;
215 nr--;
216 totalram_pages++;
218 spin_unlock(&cmm_lock);
219 cmm_dbg("End request with %ld pages unfulfilled\n", nr);
220 return nr;
224 * cmm_oom_notify - OOM notifier
225 * @self: notifier block struct
226 * @dummy: not used
227 * @parm: returned - number of pages freed
229 * Return value:
230 * NOTIFY_OK
232 static int cmm_oom_notify(struct notifier_block *self,
233 unsigned long dummy, void *parm)
235 unsigned long *freed = parm;
236 long nr = KB2PAGES(oom_kb);
238 cmm_dbg("OOM processing started\n");
239 nr = cmm_free_pages(nr);
240 loaned_pages_target = loaned_pages;
241 *freed += KB2PAGES(oom_kb) - nr;
242 oom_freed_pages += KB2PAGES(oom_kb) - nr;
243 cmm_dbg("OOM processing complete\n");
244 return NOTIFY_OK;
248 * cmm_get_mpp - Read memory performance parameters
250 * Makes hcall to query the current page loan request from the hypervisor.
252 * Return value:
253 * nothing
255 static void cmm_get_mpp(void)
257 int rc;
258 struct hvcall_mpp_data mpp_data;
259 signed long active_pages_target, page_loan_request, target;
260 signed long total_pages = totalram_pages + loaned_pages;
261 signed long min_mem_pages = (min_mem_mb * 1024 * 1024) / PAGE_SIZE;
263 rc = h_get_mpp(&mpp_data);
265 if (rc != H_SUCCESS)
266 return;
268 page_loan_request = div_s64((s64)mpp_data.loan_request, PAGE_SIZE);
269 target = page_loan_request + (signed long)loaned_pages;
271 if (target < 0 || total_pages < min_mem_pages)
272 target = 0;
274 if (target > oom_freed_pages)
275 target -= oom_freed_pages;
276 else
277 target = 0;
279 active_pages_target = total_pages - target;
281 if (min_mem_pages > active_pages_target)
282 target = total_pages - min_mem_pages;
284 if (target < 0)
285 target = 0;
287 loaned_pages_target = target;
289 cmm_dbg("delta = %ld, loaned = %lu, target = %lu, oom = %lu, totalram = %lu\n",
290 page_loan_request, loaned_pages, loaned_pages_target,
291 oom_freed_pages, totalram_pages);
294 static struct notifier_block cmm_oom_nb = {
295 .notifier_call = cmm_oom_notify
299 * cmm_thread - CMM task thread
300 * @dummy: not used
302 * Return value:
305 static int cmm_thread(void *dummy)
307 unsigned long timeleft;
309 while (1) {
310 timeleft = msleep_interruptible(delay * 1000);
312 if (kthread_should_stop() || timeleft)
313 break;
315 if (mutex_trylock(&hotplug_mutex)) {
316 if (hotplug_occurred) {
317 hotplug_occurred = 0;
318 mutex_unlock(&hotplug_mutex);
319 cmm_dbg("Hotplug operation has occurred, "
320 "loaning activity suspended "
321 "for %d seconds.\n",
322 hotplug_delay);
323 timeleft = msleep_interruptible(hotplug_delay *
324 1000);
325 if (kthread_should_stop() || timeleft)
326 break;
327 continue;
329 mutex_unlock(&hotplug_mutex);
330 } else {
331 cmm_dbg("Hotplug operation in progress, activity "
332 "suspended\n");
333 continue;
336 cmm_get_mpp();
338 if (loaned_pages_target > loaned_pages) {
339 if (cmm_alloc_pages(loaned_pages_target - loaned_pages))
340 loaned_pages_target = loaned_pages;
341 } else if (loaned_pages_target < loaned_pages)
342 cmm_free_pages(loaned_pages - loaned_pages_target);
344 return 0;
347 #define CMM_SHOW(name, format, args...) \
348 static ssize_t show_##name(struct device *dev, \
349 struct device_attribute *attr, \
350 char *buf) \
352 return sprintf(buf, format, ##args); \
354 static DEVICE_ATTR(name, S_IRUGO, show_##name, NULL)
356 CMM_SHOW(loaned_kb, "%lu\n", PAGES2KB(loaned_pages));
357 CMM_SHOW(loaned_target_kb, "%lu\n", PAGES2KB(loaned_pages_target));
359 static ssize_t show_oom_pages(struct device *dev,
360 struct device_attribute *attr, char *buf)
362 return sprintf(buf, "%lu\n", PAGES2KB(oom_freed_pages));
365 static ssize_t store_oom_pages(struct device *dev,
366 struct device_attribute *attr,
367 const char *buf, size_t count)
369 unsigned long val = simple_strtoul (buf, NULL, 10);
371 if (!capable(CAP_SYS_ADMIN))
372 return -EPERM;
373 if (val != 0)
374 return -EBADMSG;
376 oom_freed_pages = 0;
377 return count;
380 static DEVICE_ATTR(oom_freed_kb, S_IWUSR | S_IRUGO,
381 show_oom_pages, store_oom_pages);
383 static struct device_attribute *cmm_attrs[] = {
384 &dev_attr_loaned_kb,
385 &dev_attr_loaned_target_kb,
386 &dev_attr_oom_freed_kb,
389 static struct bus_type cmm_subsys = {
390 .name = "cmm",
391 .dev_name = "cmm",
395 * cmm_sysfs_register - Register with sysfs
397 * Return value:
398 * 0 on success / other on failure
400 static int cmm_sysfs_register(struct device *dev)
402 int i, rc;
404 if ((rc = subsys_system_register(&cmm_subsys, NULL)))
405 return rc;
407 dev->id = 0;
408 dev->bus = &cmm_subsys;
410 if ((rc = device_register(dev)))
411 goto subsys_unregister;
413 for (i = 0; i < ARRAY_SIZE(cmm_attrs); i++) {
414 if ((rc = device_create_file(dev, cmm_attrs[i])))
415 goto fail;
418 return 0;
420 fail:
421 while (--i >= 0)
422 device_remove_file(dev, cmm_attrs[i]);
423 device_unregister(dev);
424 subsys_unregister:
425 bus_unregister(&cmm_subsys);
426 return rc;
430 * cmm_unregister_sysfs - Unregister from sysfs
433 static void cmm_unregister_sysfs(struct device *dev)
435 int i;
437 for (i = 0; i < ARRAY_SIZE(cmm_attrs); i++)
438 device_remove_file(dev, cmm_attrs[i]);
439 device_unregister(dev);
440 bus_unregister(&cmm_subsys);
444 * cmm_reboot_notifier - Make sure pages are not still marked as "loaned"
447 static int cmm_reboot_notifier(struct notifier_block *nb,
448 unsigned long action, void *unused)
450 if (action == SYS_RESTART) {
451 if (cmm_thread_ptr)
452 kthread_stop(cmm_thread_ptr);
453 cmm_thread_ptr = NULL;
454 cmm_free_pages(loaned_pages);
456 return NOTIFY_DONE;
459 static struct notifier_block cmm_reboot_nb = {
460 .notifier_call = cmm_reboot_notifier,
464 * cmm_count_pages - Count the number of pages loaned in a particular range.
466 * @arg: memory_isolate_notify structure with address range and count
468 * Return value:
469 * 0 on success
471 static unsigned long cmm_count_pages(void *arg)
473 struct memory_isolate_notify *marg = arg;
474 struct cmm_page_array *pa;
475 unsigned long start = (unsigned long)pfn_to_kaddr(marg->start_pfn);
476 unsigned long end = start + (marg->nr_pages << PAGE_SHIFT);
477 unsigned long idx;
479 spin_lock(&cmm_lock);
480 pa = cmm_page_list;
481 while (pa) {
482 if ((unsigned long)pa >= start && (unsigned long)pa < end)
483 marg->pages_found++;
484 for (idx = 0; idx < pa->index; idx++)
485 if (pa->page[idx] >= start && pa->page[idx] < end)
486 marg->pages_found++;
487 pa = pa->next;
489 spin_unlock(&cmm_lock);
490 return 0;
494 * cmm_memory_isolate_cb - Handle memory isolation notifier calls
495 * @self: notifier block struct
496 * @action: action to take
497 * @arg: struct memory_isolate_notify data for handler
499 * Return value:
500 * NOTIFY_OK or notifier error based on subfunction return value
502 static int cmm_memory_isolate_cb(struct notifier_block *self,
503 unsigned long action, void *arg)
505 int ret = 0;
507 if (action == MEM_ISOLATE_COUNT)
508 ret = cmm_count_pages(arg);
510 return notifier_from_errno(ret);
513 static struct notifier_block cmm_mem_isolate_nb = {
514 .notifier_call = cmm_memory_isolate_cb,
515 .priority = CMM_MEM_ISOLATE_PRI
519 * cmm_mem_going_offline - Unloan pages where memory is to be removed
520 * @arg: memory_notify structure with page range to be offlined
522 * Return value:
523 * 0 on success
525 static int cmm_mem_going_offline(void *arg)
527 struct memory_notify *marg = arg;
528 unsigned long start_page = (unsigned long)pfn_to_kaddr(marg->start_pfn);
529 unsigned long end_page = start_page + (marg->nr_pages << PAGE_SHIFT);
530 struct cmm_page_array *pa_curr, *pa_last, *npa;
531 unsigned long idx;
532 unsigned long freed = 0;
534 cmm_dbg("Memory going offline, searching 0x%lx (%ld pages).\n",
535 start_page, marg->nr_pages);
536 spin_lock(&cmm_lock);
538 /* Search the page list for pages in the range to be offlined */
539 pa_last = pa_curr = cmm_page_list;
540 while (pa_curr) {
541 for (idx = (pa_curr->index - 1); (idx + 1) > 0; idx--) {
542 if ((pa_curr->page[idx] < start_page) ||
543 (pa_curr->page[idx] >= end_page))
544 continue;
546 plpar_page_set_active(__pa(pa_curr->page[idx]));
547 free_page(pa_curr->page[idx]);
548 freed++;
549 loaned_pages--;
550 totalram_pages++;
551 pa_curr->page[idx] = pa_last->page[--pa_last->index];
552 if (pa_last->index == 0) {
553 if (pa_curr == pa_last)
554 pa_curr = pa_last->next;
555 pa_last = pa_last->next;
556 free_page((unsigned long)cmm_page_list);
557 cmm_page_list = pa_last;
558 continue;
561 pa_curr = pa_curr->next;
564 /* Search for page list structures in the range to be offlined */
565 pa_last = NULL;
566 pa_curr = cmm_page_list;
567 while (pa_curr) {
568 if (((unsigned long)pa_curr >= start_page) &&
569 ((unsigned long)pa_curr < end_page)) {
570 npa = (struct cmm_page_array *)__get_free_page(
571 GFP_NOIO | __GFP_NOWARN |
572 __GFP_NORETRY | __GFP_NOMEMALLOC);
573 if (!npa) {
574 spin_unlock(&cmm_lock);
575 cmm_dbg("Failed to allocate memory for list "
576 "management. Memory hotplug "
577 "failed.\n");
578 return ENOMEM;
580 memcpy(npa, pa_curr, PAGE_SIZE);
581 if (pa_curr == cmm_page_list)
582 cmm_page_list = npa;
583 if (pa_last)
584 pa_last->next = npa;
585 free_page((unsigned long) pa_curr);
586 freed++;
587 pa_curr = npa;
590 pa_last = pa_curr;
591 pa_curr = pa_curr->next;
594 spin_unlock(&cmm_lock);
595 cmm_dbg("Released %ld pages in the search range.\n", freed);
597 return 0;
601 * cmm_memory_cb - Handle memory hotplug notifier calls
602 * @self: notifier block struct
603 * @action: action to take
604 * @arg: struct memory_notify data for handler
606 * Return value:
607 * NOTIFY_OK or notifier error based on subfunction return value
610 static int cmm_memory_cb(struct notifier_block *self,
611 unsigned long action, void *arg)
613 int ret = 0;
615 switch (action) {
616 case MEM_GOING_OFFLINE:
617 mutex_lock(&hotplug_mutex);
618 hotplug_occurred = 1;
619 ret = cmm_mem_going_offline(arg);
620 break;
621 case MEM_OFFLINE:
622 case MEM_CANCEL_OFFLINE:
623 mutex_unlock(&hotplug_mutex);
624 cmm_dbg("Memory offline operation complete.\n");
625 break;
626 case MEM_GOING_ONLINE:
627 case MEM_ONLINE:
628 case MEM_CANCEL_ONLINE:
629 break;
632 return notifier_from_errno(ret);
635 static struct notifier_block cmm_mem_nb = {
636 .notifier_call = cmm_memory_cb,
637 .priority = CMM_MEM_HOTPLUG_PRI
641 * cmm_init - Module initialization
643 * Return value:
644 * 0 on success / other on failure
646 static int cmm_init(void)
648 int rc = -ENOMEM;
650 if (!firmware_has_feature(FW_FEATURE_CMO))
651 return -EOPNOTSUPP;
653 if ((rc = register_oom_notifier(&cmm_oom_nb)) < 0)
654 return rc;
656 if ((rc = register_reboot_notifier(&cmm_reboot_nb)))
657 goto out_oom_notifier;
659 if ((rc = cmm_sysfs_register(&cmm_dev)))
660 goto out_reboot_notifier;
662 if (register_memory_notifier(&cmm_mem_nb) ||
663 register_memory_isolate_notifier(&cmm_mem_isolate_nb))
664 goto out_unregister_notifier;
666 if (cmm_disabled)
667 return rc;
669 cmm_thread_ptr = kthread_run(cmm_thread, NULL, "cmmthread");
670 if (IS_ERR(cmm_thread_ptr)) {
671 rc = PTR_ERR(cmm_thread_ptr);
672 goto out_unregister_notifier;
675 return rc;
677 out_unregister_notifier:
678 unregister_memory_notifier(&cmm_mem_nb);
679 unregister_memory_isolate_notifier(&cmm_mem_isolate_nb);
680 cmm_unregister_sysfs(&cmm_dev);
681 out_reboot_notifier:
682 unregister_reboot_notifier(&cmm_reboot_nb);
683 out_oom_notifier:
684 unregister_oom_notifier(&cmm_oom_nb);
685 return rc;
689 * cmm_exit - Module exit
691 * Return value:
692 * nothing
694 static void cmm_exit(void)
696 if (cmm_thread_ptr)
697 kthread_stop(cmm_thread_ptr);
698 unregister_oom_notifier(&cmm_oom_nb);
699 unregister_reboot_notifier(&cmm_reboot_nb);
700 unregister_memory_notifier(&cmm_mem_nb);
701 unregister_memory_isolate_notifier(&cmm_mem_isolate_nb);
702 cmm_free_pages(loaned_pages);
703 cmm_unregister_sysfs(&cmm_dev);
707 * cmm_set_disable - Disable/Enable CMM
709 * Return value:
710 * 0 on success / other on failure
712 static int cmm_set_disable(const char *val, struct kernel_param *kp)
714 int disable = simple_strtoul(val, NULL, 10);
716 if (disable != 0 && disable != 1)
717 return -EINVAL;
719 if (disable && !cmm_disabled) {
720 if (cmm_thread_ptr)
721 kthread_stop(cmm_thread_ptr);
722 cmm_thread_ptr = NULL;
723 cmm_free_pages(loaned_pages);
724 } else if (!disable && cmm_disabled) {
725 cmm_thread_ptr = kthread_run(cmm_thread, NULL, "cmmthread");
726 if (IS_ERR(cmm_thread_ptr))
727 return PTR_ERR(cmm_thread_ptr);
730 cmm_disabled = disable;
731 return 0;
734 module_param_call(disable, cmm_set_disable, param_get_uint,
735 &cmm_disabled, S_IRUGO | S_IWUSR);
736 MODULE_PARM_DESC(disable, "Disable CMM. Set to 1 to disable. "
737 "[Default=" __stringify(CMM_DISABLE) "]");
739 module_init(cmm_init);
740 module_exit(cmm_exit);