aboutsummaryrefslogtreecommitdiff
path: root/arch/powerpc/platforms/pseries/cmm.c
blob: 6567439fe78dda4512e0524332255df66b5816a1 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
/*
 * Collaborative memory management interface.
 *
 * Copyright (C) 2008 IBM Corporation
 * Author(s): Brian King (brking@linux.vnet.ibm.com),
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

#include <linux/ctype.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/kthread.h>
#include <linux/module.h>
#include <linux/oom.h>
#include <linux/reboot.h>
#include <linux/sched.h>
#include <linux/stringify.h>
#include <linux/swap.h>
#include <linux/sysdev.h>
#include <asm/firmware.h>
#include <asm/hvcall.h>
#include <asm/mmu.h>
#include <asm/pgalloc.h>
#include <asm/uaccess.h>

#include "plpar_wrappers.h"

#define CMM_DRIVER_VERSION	"1.0.0"
#define CMM_DEFAULT_DELAY	1
#define CMM_DEBUG			0
#define CMM_DISABLE		0
#define CMM_OOM_KB		1024
#define CMM_MIN_MEM_MB		256
#define KB2PAGES(_p)		((_p)>>(PAGE_SHIFT-10))
#define PAGES2KB(_p)		((_p)<<(PAGE_SHIFT-10))

static unsigned int delay = CMM_DEFAULT_DELAY;
static unsigned int oom_kb = CMM_OOM_KB;
static unsigned int cmm_debug = CMM_DEBUG;
static unsigned int cmm_disabled = CMM_DISABLE;
static unsigned long min_mem_mb = CMM_MIN_MEM_MB;
static struct sys_device cmm_sysdev;

MODULE_AUTHOR("Brian King <brking@linux.vnet.ibm.com>");
MODULE_DESCRIPTION("IBM System p Collaborative Memory Manager");
MODULE_LICENSE("GPL");
MODULE_VERSION(CMM_DRIVER_VERSION);

module_param_named(delay, delay, uint, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(delay, "Delay (in seconds) between polls to query hypervisor paging requests. "
		 "[Default=" __stringify(CMM_DEFAULT_DELAY) "]");
module_param_named(oom_kb, oom_kb, uint, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(oom_kb, "Amount of memory in kb to free on OOM. "
		 "[Default=" __stringify(CMM_OOM_KB) "]");
module_param_named(min_mem_mb, min_mem_mb, ulong, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(min_mem_mb, "Minimum amount of memory (in MB) to not balloon. "
		 "[Default=" __stringify(CMM_MIN_MEM_MB) "]");
module_param_named(debug, cmm_debug, uint, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(debug, "Enable module debugging logging. Set to 1 to enable. "
		 "[Default=" __stringify(CMM_DEBUG) "]");

#define CMM_NR_PAGES ((PAGE_SIZE - sizeof(void *) - sizeof(unsigned long)) / sizeof(unsigned long))

#define cmm_dbg(...) if (cmm_debug) { printk(KERN_INFO "cmm: "__VA_ARGS__); }

struct cmm_page_array {
	struct cmm_page_array *next;
	unsigned long index;
	unsigned long page[CMM_NR_PAGES];
};

static unsigned long loaned_pages;
static unsigned long loaned_pages_target;
static unsigned long oom_freed_pages;

static struct cmm_page_array *cmm_page_list;
static DEFINE_SPINLOCK(cmm_lock);

static struct task_struct *cmm_thread_ptr;

/**
 * cmm_alloc_pages - Allocate pages and mark them as loaned
 * @nr:	number of pages to allocate
 *
 * Return value:
 * 	number of pages requested to be allocated which were not
 **/
static long cmm_alloc_pages(long nr)
{
	struct cmm_page_array *pa, *npa;
	unsigned long addr;
	long rc;

	cmm_dbg("Begin request for %ld pages\n", nr);

	while (nr) {
		addr = __get_free_page(GFP_NOIO | __GFP_NOWARN |
				       __GFP_NORETRY | __GFP_NOMEMALLOC);
		if (!addr)
			break;
		spin_lock(&cmm_lock);
		pa = cmm_page_list;
		if (!pa || pa->index >= CMM_NR_PAGES) {
			/* Need a new page for the page list. */
			spin_unlock(&cmm_lock);
			npa = (struct cmm_page_array *)__get_free_page(GFP_NOIO | __GFP_NOWARN |
								       __GFP_NORETRY | __GFP_NOMEMALLOC);
			if (!npa) {
				pr_info("%s: Can not allocate new page list\n", __func__);
				free_page(addr);
				break;
			}
			spin_lock(&cmm_lock);
			pa = cmm_page_list;

			if (!pa || pa->index >= CMM_NR_PAGES) {
				npa->next = pa;
				npa->index = 0;
				pa = npa;
				cmm_page_list = pa;
			} else
				free_page((unsigned long) npa);
		}

		if ((rc = plpar_page_set_loaned(__pa(addr)))) {
			pr_err("%s: Can not set page to loaned. rc=%ld\n", __func__, rc);
			spin_unlock(&cmm_lock);
			free_page(addr);
			break;
		}

		pa->page[pa->index++] = addr;
		loaned_pages++;
		totalram_pages--;
		spin_unlock(&cmm_lock);
		nr--;
	}

	cmm_dbg("End request with %ld pages unfulfilled\n", nr);
	return nr;
}

/**
 * cmm_free_pages - Free pages and mark them as active
 * @nr:	number of pages to free
 *
 * Return value:
 * 	number of pages requested to be freed which were not
 **/
static long cmm_free_pages(long nr)
{
	struct cmm_page_array *pa;
	unsigned long addr;

	cmm_dbg("Begin free of %ld pages.\n", nr);
	spin_lock(&cmm_lock);
	pa = cmm_page_list;
	while (nr) {
		if (!pa || pa->index <= 0)
			break;
		addr = pa->page[--pa->index];

		if (pa->index == 0) {
			pa = pa->next;
			free_page((unsigned long) cmm_page_list);
			cmm_page_list = pa;
		}

		plpar_page_set_active(__pa(addr));
		free_page(addr);
		loaned_pages--;
		nr--;
		totalram_pages++;
	}
	spin_unlock(&cmm_lock);
	cmm_dbg("End request with %ld pages unfulfilled\n", nr);
	return nr;
}

/**
 * cmm_oom_notify - OOM notifier
 * @self:	notifier block struct
 * @dummy:	not used
 * @parm:	returned - number of pages freed
 *
 * Return value:
 * 	NOTIFY_OK
 **/
static int cmm_oom_notify(struct notifier_block *self,
			  unsigned long dummy, void *parm)
{
	unsigned long *freed = parm;
	long nr = KB2PAGES(oom_kb);

	cmm_dbg("OOM processing started\n");
	nr = cmm_free_pages(nr);
	loaned_pages_target = loaned_pages;
	*freed += KB2PAGES(oom_kb) - nr;
	oom_freed_pages += KB2PAGES(oom_kb) - nr;
	cmm_dbg("OOM processing complete\n");
	return NOTIFY_OK;
}

/**
 * cmm_get_mpp - Read memory performance parameters
 *
 * Makes hcall to query the current page loan request from the hypervisor.
 *
 * Return value:
 * 	nothing
 **/
static void cmm_get_mpp(void)
{
	int rc;
	struct hvcall_mpp_data mpp_data;
	unsigned long active_pages_target;
	signed long page_loan_request;

	rc = h_get_mpp(&mpp_data);

	if (rc != H_SUCCESS)
		return;

	page_loan_request = div_s64((s64)mpp_data.loan_request, PAGE_SIZE);
	loaned_pages_target = page_loan_request + loaned_pages;
	if (loaned_pages_target > oom_freed_pages)
		loaned_pages_target -= oom_freed_pages;
	else
		loaned_pages_target = 0;

	active_pages_target = totalram_pages + loaned_pages - loaned_pages_target;

	if ((min_mem_mb * 1024 * 1024) > (active_pages_target * PAGE_SIZE))
		loaned_pages_target = totalram_pages + loaned_pages -
			((min_mem_mb * 1024 * 1024) / PAGE_SIZE);

	cmm_dbg("delta = %ld, loaned = %lu, target = %lu, oom = %lu, totalram = %lu\n",
		page_loan_request, loaned_pages, loaned_pages_target,
		oom_freed_pages, totalram_pages);
}

static struct notifier_block cmm_oom_nb = {
	.notifier_call = cmm_oom_notify
};

/**
 * cmm_thread - CMM task thread
 * @dummy:	not used
 *
 * Return value:
 * 	0
 **/
static int cmm_thread(void *dummy)
{
	unsigned long timeleft;

	while (1) {
		timeleft = msleep_interruptible(delay * 1000);

		if (kthread_should_stop() || timeleft) {
			loaned_pages_target = loaned_pages;
			break;
		}

		cmm_get_mpp();

		if (loaned_pages_target > loaned_pages) {
			if (cmm_alloc_pages(loaned_pages_target - loaned_pages))
				loaned_pages_target = loaned_pages;
		} else if (loaned_pages_target < loaned_pages)
			cmm_free_pages(loaned_pages - loaned_pages_target);
	}
	return 0;
}

#define CMM_SHOW(name, format, args...)			\
	static ssize_t show_##name(struct sys_device *dev,	\
				   struct sysdev_attribute *attr,	\
				   char *buf)			\
	{							\
		return sprintf(buf, format, ##args);		\
	}							\
	static SYSDEV_ATTR(name, S_IRUGO, show_##name, NULL)

CMM_SHOW(loaned_kb, "%lu\n", PAGES2KB(loaned_pages));
CMM_SHOW(loaned_target_kb, "%lu\n", PAGES2KB(loaned_pages_target));

static ssize_t show_oom_pages(struct sys_device *dev,
			      struct sysdev_attribute *attr, char *buf)
{
	return sprintf(buf, "%lu\n", PAGES2KB(oom_freed_pages));
}

static ssize_t store_oom_pages(struct sys_device *dev,
			       struct sysdev_attribute *attr,
			       const char *buf, size_t count)
{
	unsigned long val = simple_strtoul (buf, NULL, 10);

	if (!capable(CAP_SYS_ADMIN))
		return -EPERM;
	if (val != 0)
		return -EBADMSG;

	oom_freed_pages = 0;
	return count;
}

static SYSDEV_ATTR(oom_freed_kb, S_IWUSR| S_IRUGO,
		   show_oom_pages, store_oom_pages);

static struct sysdev_attribute *cmm_attrs[] = {
	&attr_loaned_kb,
	&attr_loaned_target_kb,
	&attr_oom_freed_kb,
};

static struct sysdev_class cmm_sysdev_class = {
	.name = "cmm",
};

/**
 * cmm_sysfs_register - Register with sysfs
 *
 * Return value:
 * 	0 on success / other on failure
 **/
static int cmm_sysfs_register(struct sys_device *sysdev)
{
	int i, rc;

	if ((rc = sysdev_class_register(&cmm_sysdev_class)))
		return rc;

	sysdev->id = 0;
	sysdev->cls = &cmm_sysdev_class;

	if ((rc = sysdev_register(sysdev)))
		goto class_unregister;

	for (i = 0; i < ARRAY_SIZE(cmm_attrs); i++) {
		if ((rc = sysdev_create_file(sysdev, cmm_attrs[i])))
			goto fail;
	}

	return 0;

fail:
	while (--i >= 0)
		sysdev_remove_file(sysdev, cmm_attrs[i]);
	sysdev_unregister(sysdev);
class_unregister:
	sysdev_class_unregister(&cmm_sysdev_class);
	return rc;
}

/**
 * cmm_unregister_sysfs - Unregister from sysfs
 *
 **/
static void cmm_unregister_sysfs(struct sys_device *sysdev)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(cmm_attrs); i++)
		sysdev_remove_file(sysdev, cmm_attrs[i]);
	sysdev_unregister(sysdev);
	sysdev_class_unregister(&cmm_sysdev_class);
}

/**
 * cmm_reboot_notifier - Make sure pages are not still marked as "loaned"
 *
 **/
static int cmm_reboot_notifier(struct notifier_block *nb,
			       unsigned long action, void *unused)
{
	if (action == SYS_RESTART) {
		if (cmm_thread_ptr)
			kthread_stop(cmm_thread_ptr);
		cmm_thread_ptr = NULL;
		cmm_free_pages(loaned_pages);
	}
	return NOTIFY_DONE;
}

static struct notifier_block cmm_reboot_nb = {
	.notifier_call = cmm_reboot_notifier,
};

/**
 * cmm_init - Module initialization
 *
 * Return value:
 * 	0 on success / other on failure
 **/
static int cmm_init(void)
{
	int rc = -ENOMEM;

	if (!firmware_has_feature(FW_FEATURE_CMO))
		return -EOPNOTSUPP;

	if ((rc = register_oom_notifier(&cmm_oom_nb)) < 0)
		return rc;

	if ((rc = register_reboot_notifier(&cmm_reboot_nb)))
		goto out_oom_notifier;

	if ((rc = cmm_sysfs_register(&cmm_sysdev)))
		goto out_reboot_notifier;

	if (cmm_disabled)
		return rc;

	cmm_thread_ptr = kthread_run(cmm_thread, NULL, "cmmthread");
	if (IS_ERR(cmm_thread_ptr)) {
		rc = PTR_ERR(cmm_thread_ptr);
		goto out_unregister_sysfs;
	}

	return rc;

out_unregister_sysfs:
	cmm_unregister_sysfs(&cmm_sysdev);
out_reboot_notifier:
	unregister_reboot_notifier(&cmm_reboot_nb);
out_oom_notifier:
	unregister_oom_notifier(&cmm_oom_nb);
	return rc;
}

/**
 * cmm_exit - Module exit
 *
 * Return value:
 * 	nothing
 **/
static void cmm_exit(void)
{
	if (cmm_thread_ptr)
		kthread_stop(cmm_thread_ptr);
	unregister_oom_notifier(&cmm_oom_nb);
	unregister_reboot_notifier(&cmm_reboot_nb);
	cmm_free_pages(loaned_pages);
	cmm_unregister_sysfs(&cmm_sysdev);
}

/**
 * cmm_set_disable - Disable/Enable CMM
 *
 * Return value:
 * 	0 on success / other on failure
 **/
static int cmm_set_disable(const char *val, struct kernel_param *kp)
{
	int disable = simple_strtoul(val, NULL, 10);

	if (disable != 0 && disable != 1)
		return -EINVAL;

	if (disable && !cmm_disabled) {
		if (cmm_thread_ptr)
			kthread_stop(cmm_thread_ptr);
		cmm_thread_ptr = NULL;
		cmm_free_pages(loaned_pages);
	} else if (!disable && cmm_disabled) {
		cmm_thread_ptr = kthread_run(cmm_thread, NULL, "cmmthread");
		if (IS_ERR(cmm_thread_ptr))
			return PTR_ERR(cmm_thread_ptr);
	}

	cmm_disabled = disable;
	return 0;
}

module_param_call(disable, cmm_set_disable, param_get_uint,
		  &cmm_disabled, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(disable, "Disable CMM. Set to 1 to disable. "
		 "[Default=" __stringify(CMM_DISABLE) "]");

module_init(cmm_init);
module_exit(cmm_exit);