powerpc: Add kdump support to Collaborative Memory Manager
[linux-2.6.git] / arch / powerpc / platforms / pseries / cmm.c
blobbcdcf0ccc8d799ffde04e138e1b6fa2736d968e2
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/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>
42 #include "plpar_wrappers.h"
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))
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;
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);
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) "]");
78 #define CMM_NR_PAGES ((PAGE_SIZE - sizeof(void *) - sizeof(unsigned long)) / sizeof(unsigned long))
80 #define cmm_dbg(...) if (cmm_debug) { printk(KERN_INFO "cmm: "__VA_ARGS__); }
82 struct cmm_page_array {
83 struct cmm_page_array *next;
84 unsigned long index;
85 unsigned long page[CMM_NR_PAGES];
88 static unsigned long loaned_pages;
89 static unsigned long loaned_pages_target;
90 static unsigned long oom_freed_pages;
92 static struct cmm_page_array *cmm_page_list;
93 static DEFINE_SPINLOCK(cmm_lock);
95 static struct task_struct *cmm_thread_ptr;
97 /**
98 * cmm_alloc_pages - Allocate pages and mark them as loaned
99 * @nr: number of pages to allocate
101 * Return value:
102 * number of pages requested to be allocated which were not
104 static long cmm_alloc_pages(long nr)
106 struct cmm_page_array *pa, *npa;
107 unsigned long addr;
108 long rc;
110 cmm_dbg("Begin request for %ld pages\n", nr);
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;
129 spin_lock(&cmm_lock);
130 pa = cmm_page_list;
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);
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;
148 pa->page[pa->index++] = addr;
149 loaned_pages++;
150 totalram_pages--;
151 spin_unlock(&cmm_lock);
152 nr--;
155 cmm_dbg("End request with %ld pages unfulfilled\n", nr);
156 return nr;
160 * cmm_free_pages - Free pages and mark them as active
161 * @nr: number of pages to free
163 * Return value:
164 * number of pages requested to be freed which were not
166 static long cmm_free_pages(long nr)
168 struct cmm_page_array *pa;
169 unsigned long addr;
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];
179 if (pa->index == 0) {
180 pa = pa->next;
181 free_page((unsigned long) cmm_page_list);
182 cmm_page_list = pa;
185 plpar_page_set_active(__pa(addr));
186 free_page(addr);
187 loaned_pages--;
188 nr--;
189 totalram_pages++;
191 spin_unlock(&cmm_lock);
192 cmm_dbg("End request with %ld pages unfulfilled\n", nr);
193 return nr;
197 * cmm_oom_notify - OOM notifier
198 * @self: notifier block struct
199 * @dummy: not used
200 * @parm: returned - number of pages freed
202 * Return value:
203 * NOTIFY_OK
205 static int cmm_oom_notify(struct notifier_block *self,
206 unsigned long dummy, void *parm)
208 unsigned long *freed = parm;
209 long nr = KB2PAGES(oom_kb);
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;
221 * cmm_get_mpp - Read memory performance parameters
223 * Makes hcall to query the current page loan request from the hypervisor.
225 * Return value:
226 * nothing
228 static void cmm_get_mpp(void)
230 int rc;
231 struct hvcall_mpp_data mpp_data;
232 signed long active_pages_target, page_loan_request, target;
233 signed long total_pages = totalram_pages + loaned_pages;
234 signed long min_mem_pages = (min_mem_mb * 1024 * 1024) / PAGE_SIZE;
236 rc = h_get_mpp(&mpp_data);
238 if (rc != H_SUCCESS)
239 return;
241 page_loan_request = div_s64((s64)mpp_data.loan_request, PAGE_SIZE);
242 target = page_loan_request + (signed long)loaned_pages;
244 if (target < 0 || total_pages < min_mem_pages)
245 target = 0;
247 if (target > oom_freed_pages)
248 target -= oom_freed_pages;
249 else
250 target = 0;
252 active_pages_target = total_pages - target;
254 if (min_mem_pages > active_pages_target)
255 target = total_pages - min_mem_pages;
257 if (target < 0)
258 target = 0;
260 loaned_pages_target = target;
262 cmm_dbg("delta = %ld, loaned = %lu, target = %lu, oom = %lu, totalram = %lu\n",
263 page_loan_request, loaned_pages, loaned_pages_target,
264 oom_freed_pages, totalram_pages);
267 static struct notifier_block cmm_oom_nb = {
268 .notifier_call = cmm_oom_notify
272 * cmm_thread - CMM task thread
273 * @dummy: not used
275 * Return value:
278 static int cmm_thread(void *dummy)
280 unsigned long timeleft;
282 while (1) {
283 timeleft = msleep_interruptible(delay * 1000);
285 if (kthread_should_stop() || timeleft) {
286 loaned_pages_target = loaned_pages;
287 break;
290 cmm_get_mpp();
292 if (loaned_pages_target > loaned_pages) {
293 if (cmm_alloc_pages(loaned_pages_target - loaned_pages))
294 loaned_pages_target = loaned_pages;
295 } else if (loaned_pages_target < loaned_pages)
296 cmm_free_pages(loaned_pages - loaned_pages_target);
298 return 0;
301 #define CMM_SHOW(name, format, args...) \
302 static ssize_t show_##name(struct sys_device *dev, \
303 struct sysdev_attribute *attr, \
304 char *buf) \
306 return sprintf(buf, format, ##args); \
308 static SYSDEV_ATTR(name, S_IRUGO, show_##name, NULL)
310 CMM_SHOW(loaned_kb, "%lu\n", PAGES2KB(loaned_pages));
311 CMM_SHOW(loaned_target_kb, "%lu\n", PAGES2KB(loaned_pages_target));
313 static ssize_t show_oom_pages(struct sys_device *dev,
314 struct sysdev_attribute *attr, char *buf)
316 return sprintf(buf, "%lu\n", PAGES2KB(oom_freed_pages));
319 static ssize_t store_oom_pages(struct sys_device *dev,
320 struct sysdev_attribute *attr,
321 const char *buf, size_t count)
323 unsigned long val = simple_strtoul (buf, NULL, 10);
325 if (!capable(CAP_SYS_ADMIN))
326 return -EPERM;
327 if (val != 0)
328 return -EBADMSG;
330 oom_freed_pages = 0;
331 return count;
334 static SYSDEV_ATTR(oom_freed_kb, S_IWUSR| S_IRUGO,
335 show_oom_pages, store_oom_pages);
337 static struct sysdev_attribute *cmm_attrs[] = {
338 &attr_loaned_kb,
339 &attr_loaned_target_kb,
340 &attr_oom_freed_kb,
343 static struct sysdev_class cmm_sysdev_class = {
344 .name = "cmm",
348 * cmm_sysfs_register - Register with sysfs
350 * Return value:
351 * 0 on success / other on failure
353 static int cmm_sysfs_register(struct sys_device *sysdev)
355 int i, rc;
357 if ((rc = sysdev_class_register(&cmm_sysdev_class)))
358 return rc;
360 sysdev->id = 0;
361 sysdev->cls = &cmm_sysdev_class;
363 if ((rc = sysdev_register(sysdev)))
364 goto class_unregister;
366 for (i = 0; i < ARRAY_SIZE(cmm_attrs); i++) {
367 if ((rc = sysdev_create_file(sysdev, cmm_attrs[i])))
368 goto fail;
371 return 0;
373 fail:
374 while (--i >= 0)
375 sysdev_remove_file(sysdev, cmm_attrs[i]);
376 sysdev_unregister(sysdev);
377 class_unregister:
378 sysdev_class_unregister(&cmm_sysdev_class);
379 return rc;
383 * cmm_unregister_sysfs - Unregister from sysfs
386 static void cmm_unregister_sysfs(struct sys_device *sysdev)
388 int i;
390 for (i = 0; i < ARRAY_SIZE(cmm_attrs); i++)
391 sysdev_remove_file(sysdev, cmm_attrs[i]);
392 sysdev_unregister(sysdev);
393 sysdev_class_unregister(&cmm_sysdev_class);
397 * cmm_reboot_notifier - Make sure pages are not still marked as "loaned"
400 static int cmm_reboot_notifier(struct notifier_block *nb,
401 unsigned long action, void *unused)
403 if (action == SYS_RESTART) {
404 if (cmm_thread_ptr)
405 kthread_stop(cmm_thread_ptr);
406 cmm_thread_ptr = NULL;
407 cmm_free_pages(loaned_pages);
409 return NOTIFY_DONE;
412 static struct notifier_block cmm_reboot_nb = {
413 .notifier_call = cmm_reboot_notifier,
417 * cmm_init - Module initialization
419 * Return value:
420 * 0 on success / other on failure
422 static int cmm_init(void)
424 int rc = -ENOMEM;
426 if (!firmware_has_feature(FW_FEATURE_CMO))
427 return -EOPNOTSUPP;
429 if ((rc = register_oom_notifier(&cmm_oom_nb)) < 0)
430 return rc;
432 if ((rc = register_reboot_notifier(&cmm_reboot_nb)))
433 goto out_oom_notifier;
435 if ((rc = cmm_sysfs_register(&cmm_sysdev)))
436 goto out_reboot_notifier;
438 if (cmm_disabled)
439 return rc;
441 cmm_thread_ptr = kthread_run(cmm_thread, NULL, "cmmthread");
442 if (IS_ERR(cmm_thread_ptr)) {
443 rc = PTR_ERR(cmm_thread_ptr);
444 goto out_unregister_sysfs;
447 return rc;
449 out_unregister_sysfs:
450 cmm_unregister_sysfs(&cmm_sysdev);
451 out_reboot_notifier:
452 unregister_reboot_notifier(&cmm_reboot_nb);
453 out_oom_notifier:
454 unregister_oom_notifier(&cmm_oom_nb);
455 return rc;
459 * cmm_exit - Module exit
461 * Return value:
462 * nothing
464 static void cmm_exit(void)
466 if (cmm_thread_ptr)
467 kthread_stop(cmm_thread_ptr);
468 unregister_oom_notifier(&cmm_oom_nb);
469 unregister_reboot_notifier(&cmm_reboot_nb);
470 cmm_free_pages(loaned_pages);
471 cmm_unregister_sysfs(&cmm_sysdev);
475 * cmm_set_disable - Disable/Enable CMM
477 * Return value:
478 * 0 on success / other on failure
480 static int cmm_set_disable(const char *val, struct kernel_param *kp)
482 int disable = simple_strtoul(val, NULL, 10);
484 if (disable != 0 && disable != 1)
485 return -EINVAL;
487 if (disable && !cmm_disabled) {
488 if (cmm_thread_ptr)
489 kthread_stop(cmm_thread_ptr);
490 cmm_thread_ptr = NULL;
491 cmm_free_pages(loaned_pages);
492 } else if (!disable && cmm_disabled) {
493 cmm_thread_ptr = kthread_run(cmm_thread, NULL, "cmmthread");
494 if (IS_ERR(cmm_thread_ptr))
495 return PTR_ERR(cmm_thread_ptr);
498 cmm_disabled = disable;
499 return 0;
502 module_param_call(disable, cmm_set_disable, param_get_uint,
503 &cmm_disabled, S_IRUGO | S_IWUSR);
504 MODULE_PARM_DESC(disable, "Disable CMM. Set to 1 to disable. "
505 "[Default=" __stringify(CMM_DISABLE) "]");
507 module_init(cmm_init);
508 module_exit(cmm_exit);