aboutsummaryrefslogtreecommitdiff
path: root/arch/s390/mm/cmm.c
blob: 51596f429235ba1252008fd9bd0f270305d2a225 (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
/*
 *  arch/s390/mm/cmm.c
 *
 *  S390 version
 *    Copyright (C) 2003 IBM Deutschland Entwicklung GmbH, IBM Corporation
 *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
 *
 *  Collaborative memory management interface.
 */

#include <linux/config.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/sysctl.h>
#include <linux/ctype.h>

#include <asm/pgalloc.h>
#include <asm/uaccess.h>

static char *sender = "VMRMSVM";
module_param(sender, charp, 0400);
MODULE_PARM_DESC(sender,
		 "Guest name that may send SMSG messages (default VMRMSVM)");

#include "../../../drivers/s390/net/smsgiucv.h"

#define CMM_NR_PAGES ((PAGE_SIZE / sizeof(unsigned long)) - 2)

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

static long cmm_pages = 0;
static long cmm_timed_pages = 0;
static volatile long cmm_pages_target = 0;
static volatile long cmm_timed_pages_target = 0;
static long cmm_timeout_pages = 0;
static long cmm_timeout_seconds = 0;

static struct cmm_page_array *cmm_page_list = NULL;
static struct cmm_page_array *cmm_timed_page_list = NULL;

static unsigned long cmm_thread_active = 0;
static struct work_struct cmm_thread_starter;
static wait_queue_head_t cmm_thread_wait;
static struct timer_list cmm_timer;

static void cmm_timer_fn(unsigned long);
static void cmm_set_timer(void);

static long
cmm_strtoul(const char *cp, char **endp)
{
	unsigned int base = 10;

	if (*cp == '0') {
		base = 8;
		cp++;
		if ((*cp == 'x' || *cp == 'X') && isxdigit(cp[1])) {
			base = 16;
			cp++;
		}
	}
	return simple_strtoul(cp, endp, base);
}

static long
cmm_alloc_pages(long pages, long *counter, struct cmm_page_array **list)
{
	struct cmm_page_array *pa;
	unsigned long page;

	pa = *list;
	while (pages) {
		page = __get_free_page(GFP_NOIO);
		if (!page)
			break;
		if (!pa || pa->index >= CMM_NR_PAGES) {
			/* Need a new page for the page list. */
			pa = (struct cmm_page_array *)
				__get_free_page(GFP_NOIO);
			if (!pa) {
				free_page(page);
				break;
			}
			pa->next = *list;
			pa->index = 0;
			*list = pa;
		}
		diag10(page);
		pa->pages[pa->index++] = page;
		(*counter)++;
		pages--;
	}
	return pages;
}

static void
cmm_free_pages(long pages, long *counter, struct cmm_page_array **list)
{
	struct cmm_page_array *pa;
	unsigned long page;

	pa = *list;
	while (pages) {
		if (!pa || pa->index <= 0)
			break;
		page = pa->pages[--pa->index];
		if (pa->index == 0) {
			pa = pa->next;
			free_page((unsigned long) *list);
			*list = pa;
		}
		free_page(page);
		(*counter)--;
		pages--;
	}
}

static int
cmm_thread(void *dummy)
{
	int rc;

	daemonize("cmmthread");
	while (1) {
		rc = wait_event_interruptible(cmm_thread_wait,
			(cmm_pages != cmm_pages_target ||
			 cmm_timed_pages != cmm_timed_pages_target));
		if (rc == -ERESTARTSYS) {
			/* Got kill signal. End thread. */
			clear_bit(0, &cmm_thread_active);
			cmm_pages_target = cmm_pages;
			cmm_timed_pages_target = cmm_timed_pages;
			break;
		}
		if (cmm_pages_target > cmm_pages) {
			if (cmm_alloc_pages(1, &cmm_pages, &cmm_page_list))
				cmm_pages_target = cmm_pages;
		} else if (cmm_pages_target < cmm_pages) {
			cmm_free_pages(1, &cmm_pages, &cmm_page_list);
		}
		if (cmm_timed_pages_target > cmm_timed_pages) {
			if (cmm_alloc_pages(1, &cmm_timed_pages,
					   &cmm_timed_page_list))
				cmm_timed_pages_target = cmm_timed_pages;
		} else if (cmm_timed_pages_target < cmm_timed_pages) {
			cmm_free_pages(1, &cmm_timed_pages,
			       	       &cmm_timed_page_list);
		}
		if (cmm_timed_pages > 0 && !timer_pending(&cmm_timer))
			cmm_set_timer();
	}
	return 0;
}

static void
cmm_start_thread(void)
{
	kernel_thread(cmm_thread, 0, 0);
}

static void
cmm_kick_thread(void)
{
	if (!test_and_set_bit(0, &cmm_thread_active))
		schedule_work(&cmm_thread_starter);
	wake_up(&cmm_thread_wait);
}

static void
cmm_set_timer(void)
{
	if (cmm_timed_pages_target <= 0 || cmm_timeout_seconds <= 0) {
		if (timer_pending(&cmm_timer))
			del_timer(&cmm_timer);
		return;
	}
	if (timer_pending(&cmm_timer)) {
		if (mod_timer(&cmm_timer, jiffies + cmm_timeout_seconds*HZ))
			return;
	}
	cmm_timer.function = cmm_timer_fn;
	cmm_timer.data = 0;
	cmm_timer.expires = jiffies + cmm_timeout_seconds*HZ;
	add_timer(&cmm_timer);
}

static void
cmm_timer_fn(unsigned long ignored)
{
	long pages;

	pages = cmm_timed_pages_target - cmm_timeout_pages;
	if (pages < 0)
		cmm_timed_pages_target = 0;
	else
		cmm_timed_pages_target = pages;
	cmm_kick_thread();
	cmm_set_timer();
}

void
cmm_set_pages(long pages)
{
	cmm_pages_target = pages;
	cmm_kick_thread();
}

long
cmm_get_pages(void)
{
	return cmm_pages;
}

void
cmm_add_timed_pages(long pages)
{
	cmm_timed_pages_target += pages;
	cmm_kick_thread();
}

long
cmm_get_timed_pages(void)
{
	return cmm_timed_pages;
}

void
cmm_set_timeout(long pages, long seconds)
{
	cmm_timeout_pages = pages;
	cmm_timeout_seconds = seconds;
	cmm_set_timer();
}

static inline int
cmm_skip_blanks(char *cp, char **endp)
{
	char *str;

	for (str = cp; *str == ' ' || *str == '\t'; str++);
	*endp = str;
	return str != cp;
}

#ifdef CONFIG_CMM_PROC
/* These will someday get removed. */
#define VM_CMM_PAGES		1111
#define VM_CMM_TIMED_PAGES	1112
#define VM_CMM_TIMEOUT		1113

static struct ctl_table cmm_table[];

static int
cmm_pages_handler(ctl_table *ctl, int write, struct file *filp,
		  void __user *buffer, size_t *lenp, loff_t *ppos)
{
	char buf[16], *p;
	long pages;
	int len;

	if (!*lenp || (*ppos && !write)) {
		*lenp = 0;
		return 0;
	}

	if (write) {
		len = *lenp;
		if (copy_from_user(buf, buffer,
				   len > sizeof(buf) ? sizeof(buf) : len))
			return -EFAULT;
		buf[sizeof(buf) - 1] = '\0';
		cmm_skip_blanks(buf, &p);
		pages = cmm_strtoul(p, &p);
		if (ctl == &cmm_table[0])
			cmm_set_pages(pages);
		else
			cmm_add_timed_pages(pages);
	} else {
		if (ctl == &cmm_table[0])
			pages = cmm_get_pages();
		else
			pages = cmm_get_timed_pages();
		len = sprintf(buf, "%ld\n", pages);
		if (len > *lenp)
			len = *lenp;
		if (copy_to_user(buffer, buf, len))
			return -EFAULT;
	}
	*lenp = len;
	*ppos += len;
	return 0;
}

static int
cmm_timeout_handler(ctl_table *ctl, int write, struct file *filp,
		    void __user *buffer, size_t *lenp, loff_t *ppos)
{
	char buf[64], *p;
	long pages, seconds;
	int len;

	if (!*lenp || (*ppos && !write)) {
		*lenp = 0;
		return 0;
	}

	if (write) {
		len = *lenp;
		if (copy_from_user(buf, buffer,
				   len > sizeof(buf) ? sizeof(buf) : len))
			return -EFAULT;
		buf[sizeof(buf) - 1] = '\0';
		cmm_skip_blanks(buf, &p);
		pages = cmm_strtoul(p, &p);
		cmm_skip_blanks(p, &p);
		seconds = cmm_strtoul(p, &p);
		cmm_set_timeout(pages, seconds);
	} else {
		len = sprintf(buf, "%ld %ld\n",
			      cmm_timeout_pages, cmm_timeout_seconds);
		if (len > *lenp)
			len = *lenp;
		if (copy_to_user(buffer, buf, len))
			return -EFAULT;
	}
	*lenp = len;
	*ppos += len;
	return 0;
}

static struct ctl_table cmm_table[] = {
	{
		.ctl_name	= VM_CMM_PAGES,
		.procname	= "cmm_pages",
		.mode		= 0644,
		.proc_handler	= &cmm_pages_handler,
	},
	{
		.ctl_name	= VM_CMM_TIMED_PAGES,
		.procname	= "cmm_timed_pages",
		.mode		= 0644,
		.proc_handler	= &cmm_pages_handler,
	},
	{
		.ctl_name	= VM_CMM_TIMEOUT,
		.procname	= "cmm_timeout",
		.mode		= 0644,
		.proc_handler	= &cmm_timeout_handler,
	},
	{ .ctl_name = 0 }
};

static struct ctl_table cmm_dir_table[] = {
	{
		.ctl_name	= CTL_VM,
		.procname	= "vm",
		.maxlen		= 0,
		.mode		= 0555,
		.child		= cmm_table,
	},
	{ .ctl_name = 0 }
};
#endif

#ifdef CONFIG_CMM_IUCV
#define SMSG_PREFIX "CMM"
static void
cmm_smsg_target(char *from, char *msg)
{
	long pages, seconds;

	if (strlen(sender) > 0 && strcmp(from, sender) != 0)
		return;
	if (!cmm_skip_blanks(msg + strlen(SMSG_PREFIX), &msg))
		return;
	if (strncmp(msg, "SHRINK", 6) == 0) {
		if (!cmm_skip_blanks(msg + 6, &msg))
			return;
		pages = cmm_strtoul(msg, &msg);
		cmm_skip_blanks(msg, &msg);
		if (*msg == '\0')
			cmm_set_pages(pages);
	} else if (strncmp(msg, "RELEASE", 7) == 0) {
		if (!cmm_skip_blanks(msg + 7, &msg))
			return;
		pages = cmm_strtoul(msg, &msg);
		cmm_skip_blanks(msg, &msg);
		if (*msg == '\0')
			cmm_add_timed_pages(pages);
	} else if (strncmp(msg, "REUSE", 5) == 0) {
		if (!cmm_skip_blanks(msg + 5, &msg))
			return;
		pages = cmm_strtoul(msg, &msg);
		if (!cmm_skip_blanks(msg, &msg))
			return;
		seconds = cmm_strtoul(msg, &msg);
		cmm_skip_blanks(msg, &msg);
		if (*msg == '\0')
			cmm_set_timeout(pages, seconds);
	}
}
#endif

struct ctl_table_header *cmm_sysctl_header;

static int
cmm_init (void)
{
#ifdef CONFIG_CMM_PROC
	cmm_sysctl_header = register_sysctl_table(cmm_dir_table, 1);
#endif
#ifdef CONFIG_CMM_IUCV
	smsg_register_callback(SMSG_PREFIX, cmm_smsg_target);
#endif
	INIT_WORK(&cmm_thread_starter, (void *) cmm_start_thread, NULL);
	init_waitqueue_head(&cmm_thread_wait);
	init_timer(&cmm_timer);
	return 0;
}

static void
cmm_exit(void)
{
	cmm_free_pages(cmm_pages, &cmm_pages, &cmm_page_list);
	cmm_free_pages(cmm_timed_pages, &cmm_timed_pages, &cmm_timed_page_list);
#ifdef CONFIG_CMM_PROC
	unregister_sysctl_table(cmm_sysctl_header);
#endif
#ifdef CONFIG_CMM_IUCV
	smsg_unregister_callback(SMSG_PREFIX, cmm_smsg_target);
#endif
}

module_init(cmm_init);
module_exit(cmm_exit);

EXPORT_SYMBOL(cmm_set_pages);
EXPORT_SYMBOL(cmm_get_pages);
EXPORT_SYMBOL(cmm_add_timed_pages);
EXPORT_SYMBOL(cmm_get_timed_pages);
EXPORT_SYMBOL(cmm_set_timeout);

MODULE_LICENSE("GPL");