1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * Collaborative memory management interface. |
4 | * |
5 | * Copyright IBM Corp 2003, 2010 |
6 | * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>, |
7 | * |
8 | */ |
9 | |
10 | #include <linux/errno.h> |
11 | #include <linux/fs.h> |
12 | #include <linux/init.h> |
13 | #include <linux/module.h> |
14 | #include <linux/moduleparam.h> |
15 | #include <linux/gfp.h> |
16 | #include <linux/sched.h> |
17 | #include <linux/string_helpers.h> |
18 | #include <linux/sysctl.h> |
19 | #include <linux/swap.h> |
20 | #include <linux/kthread.h> |
21 | #include <linux/oom.h> |
22 | #include <linux/uaccess.h> |
23 | |
24 | #include <asm/diag.h> |
25 | |
26 | #ifdef CONFIG_CMM_IUCV |
27 | static char *cmm_default_sender = "VMRMSVM" ; |
28 | #endif |
29 | static char *sender; |
30 | module_param(sender, charp, 0400); |
31 | MODULE_PARM_DESC(sender, |
32 | "Guest name that may send SMSG messages (default VMRMSVM)" ); |
33 | |
34 | #include "../../../drivers/s390/net/smsgiucv.h" |
35 | |
36 | #define CMM_NR_PAGES ((PAGE_SIZE / sizeof(unsigned long)) - 2) |
37 | |
38 | struct cmm_page_array { |
39 | struct cmm_page_array *next; |
40 | unsigned long index; |
41 | unsigned long pages[CMM_NR_PAGES]; |
42 | }; |
43 | |
44 | static long cmm_pages; |
45 | static long cmm_timed_pages; |
46 | static volatile long cmm_pages_target; |
47 | static volatile long cmm_timed_pages_target; |
48 | static long cmm_timeout_pages; |
49 | static long cmm_timeout_seconds; |
50 | |
51 | static struct cmm_page_array *cmm_page_list; |
52 | static struct cmm_page_array *cmm_timed_page_list; |
53 | static DEFINE_SPINLOCK(cmm_lock); |
54 | |
55 | static struct task_struct *cmm_thread_ptr; |
56 | static DECLARE_WAIT_QUEUE_HEAD(cmm_thread_wait); |
57 | |
58 | static void cmm_timer_fn(struct timer_list *); |
59 | static void cmm_set_timer(void); |
60 | static DEFINE_TIMER(cmm_timer, cmm_timer_fn); |
61 | |
62 | static long cmm_alloc_pages(long nr, long *counter, |
63 | struct cmm_page_array **list) |
64 | { |
65 | struct cmm_page_array *pa, *npa; |
66 | unsigned long addr; |
67 | |
68 | while (nr) { |
69 | addr = __get_free_page(GFP_NOIO); |
70 | if (!addr) |
71 | break; |
72 | spin_lock(lock: &cmm_lock); |
73 | pa = *list; |
74 | if (!pa || pa->index >= CMM_NR_PAGES) { |
75 | /* Need a new page for the page list. */ |
76 | spin_unlock(lock: &cmm_lock); |
77 | npa = (struct cmm_page_array *) |
78 | __get_free_page(GFP_NOIO); |
79 | if (!npa) { |
80 | free_page(addr); |
81 | break; |
82 | } |
83 | spin_lock(lock: &cmm_lock); |
84 | pa = *list; |
85 | if (!pa || pa->index >= CMM_NR_PAGES) { |
86 | npa->next = pa; |
87 | npa->index = 0; |
88 | pa = npa; |
89 | *list = pa; |
90 | } else |
91 | free_page((unsigned long) npa); |
92 | } |
93 | diag10_range(virt_to_pfn((void *)addr), 1); |
94 | pa->pages[pa->index++] = addr; |
95 | (*counter)++; |
96 | spin_unlock(lock: &cmm_lock); |
97 | nr--; |
98 | } |
99 | return nr; |
100 | } |
101 | |
102 | static long cmm_free_pages(long nr, long *counter, struct cmm_page_array **list) |
103 | { |
104 | struct cmm_page_array *pa; |
105 | unsigned long addr; |
106 | |
107 | spin_lock(lock: &cmm_lock); |
108 | pa = *list; |
109 | while (nr) { |
110 | if (!pa || pa->index <= 0) |
111 | break; |
112 | addr = pa->pages[--pa->index]; |
113 | if (pa->index == 0) { |
114 | pa = pa->next; |
115 | free_page((unsigned long) *list); |
116 | *list = pa; |
117 | } |
118 | free_page(addr); |
119 | (*counter)--; |
120 | nr--; |
121 | } |
122 | spin_unlock(lock: &cmm_lock); |
123 | return nr; |
124 | } |
125 | |
126 | static int cmm_oom_notify(struct notifier_block *self, |
127 | unsigned long dummy, void *parm) |
128 | { |
129 | unsigned long *freed = parm; |
130 | long nr = 256; |
131 | |
132 | nr = cmm_free_pages(nr, counter: &cmm_timed_pages, list: &cmm_timed_page_list); |
133 | if (nr > 0) |
134 | nr = cmm_free_pages(nr, counter: &cmm_pages, list: &cmm_page_list); |
135 | cmm_pages_target = cmm_pages; |
136 | cmm_timed_pages_target = cmm_timed_pages; |
137 | *freed += 256 - nr; |
138 | return NOTIFY_OK; |
139 | } |
140 | |
141 | static struct notifier_block cmm_oom_nb = { |
142 | .notifier_call = cmm_oom_notify, |
143 | }; |
144 | |
145 | static int cmm_thread(void *dummy) |
146 | { |
147 | int rc; |
148 | |
149 | while (1) { |
150 | rc = wait_event_interruptible(cmm_thread_wait, |
151 | cmm_pages != cmm_pages_target || |
152 | cmm_timed_pages != cmm_timed_pages_target || |
153 | kthread_should_stop()); |
154 | if (kthread_should_stop() || rc == -ERESTARTSYS) { |
155 | cmm_pages_target = cmm_pages; |
156 | cmm_timed_pages_target = cmm_timed_pages; |
157 | break; |
158 | } |
159 | if (cmm_pages_target > cmm_pages) { |
160 | if (cmm_alloc_pages(nr: 1, counter: &cmm_pages, list: &cmm_page_list)) |
161 | cmm_pages_target = cmm_pages; |
162 | } else if (cmm_pages_target < cmm_pages) { |
163 | cmm_free_pages(nr: 1, counter: &cmm_pages, list: &cmm_page_list); |
164 | } |
165 | if (cmm_timed_pages_target > cmm_timed_pages) { |
166 | if (cmm_alloc_pages(nr: 1, counter: &cmm_timed_pages, |
167 | list: &cmm_timed_page_list)) |
168 | cmm_timed_pages_target = cmm_timed_pages; |
169 | } else if (cmm_timed_pages_target < cmm_timed_pages) { |
170 | cmm_free_pages(nr: 1, counter: &cmm_timed_pages, |
171 | list: &cmm_timed_page_list); |
172 | } |
173 | if (cmm_timed_pages > 0 && !timer_pending(timer: &cmm_timer)) |
174 | cmm_set_timer(); |
175 | } |
176 | return 0; |
177 | } |
178 | |
179 | static void cmm_kick_thread(void) |
180 | { |
181 | wake_up(&cmm_thread_wait); |
182 | } |
183 | |
184 | static void cmm_set_timer(void) |
185 | { |
186 | if (cmm_timed_pages_target <= 0 || cmm_timeout_seconds <= 0) { |
187 | if (timer_pending(timer: &cmm_timer)) |
188 | del_timer(timer: &cmm_timer); |
189 | return; |
190 | } |
191 | mod_timer(timer: &cmm_timer, expires: jiffies + msecs_to_jiffies(m: cmm_timeout_seconds * MSEC_PER_SEC)); |
192 | } |
193 | |
194 | static void cmm_timer_fn(struct timer_list *unused) |
195 | { |
196 | long nr; |
197 | |
198 | nr = cmm_timed_pages_target - cmm_timeout_pages; |
199 | if (nr < 0) |
200 | cmm_timed_pages_target = 0; |
201 | else |
202 | cmm_timed_pages_target = nr; |
203 | cmm_kick_thread(); |
204 | cmm_set_timer(); |
205 | } |
206 | |
207 | static void cmm_set_pages(long nr) |
208 | { |
209 | cmm_pages_target = nr; |
210 | cmm_kick_thread(); |
211 | } |
212 | |
213 | static long cmm_get_pages(void) |
214 | { |
215 | return cmm_pages; |
216 | } |
217 | |
218 | static void cmm_add_timed_pages(long nr) |
219 | { |
220 | cmm_timed_pages_target += nr; |
221 | cmm_kick_thread(); |
222 | } |
223 | |
224 | static long cmm_get_timed_pages(void) |
225 | { |
226 | return cmm_timed_pages; |
227 | } |
228 | |
229 | static void cmm_set_timeout(long nr, long seconds) |
230 | { |
231 | cmm_timeout_pages = nr; |
232 | cmm_timeout_seconds = seconds; |
233 | cmm_set_timer(); |
234 | } |
235 | |
236 | static int cmm_skip_blanks(char *cp, char **endp) |
237 | { |
238 | char *str; |
239 | |
240 | for (str = cp; *str == ' ' || *str == '\t'; str++) |
241 | ; |
242 | *endp = str; |
243 | return str != cp; |
244 | } |
245 | |
246 | static int cmm_pages_handler(struct ctl_table *ctl, int write, |
247 | void *buffer, size_t *lenp, loff_t *ppos) |
248 | { |
249 | long nr = cmm_get_pages(); |
250 | struct ctl_table ctl_entry = { |
251 | .procname = ctl->procname, |
252 | .data = &nr, |
253 | .maxlen = sizeof(long), |
254 | }; |
255 | int rc; |
256 | |
257 | rc = proc_doulongvec_minmax(&ctl_entry, write, buffer, lenp, ppos); |
258 | if (rc < 0 || !write) |
259 | return rc; |
260 | |
261 | cmm_set_pages(nr); |
262 | return 0; |
263 | } |
264 | |
265 | static int cmm_timed_pages_handler(struct ctl_table *ctl, int write, |
266 | void *buffer, size_t *lenp, |
267 | loff_t *ppos) |
268 | { |
269 | long nr = cmm_get_timed_pages(); |
270 | struct ctl_table ctl_entry = { |
271 | .procname = ctl->procname, |
272 | .data = &nr, |
273 | .maxlen = sizeof(long), |
274 | }; |
275 | int rc; |
276 | |
277 | rc = proc_doulongvec_minmax(&ctl_entry, write, buffer, lenp, ppos); |
278 | if (rc < 0 || !write) |
279 | return rc; |
280 | |
281 | cmm_add_timed_pages(nr); |
282 | return 0; |
283 | } |
284 | |
285 | static int cmm_timeout_handler(struct ctl_table *ctl, int write, |
286 | void *buffer, size_t *lenp, loff_t *ppos) |
287 | { |
288 | char buf[64], *p; |
289 | long nr, seconds; |
290 | unsigned int len; |
291 | |
292 | if (!*lenp || (*ppos && !write)) { |
293 | *lenp = 0; |
294 | return 0; |
295 | } |
296 | |
297 | if (write) { |
298 | len = min(*lenp, sizeof(buf)); |
299 | memcpy(buf, buffer, len); |
300 | buf[len - 1] = '\0'; |
301 | cmm_skip_blanks(cp: buf, endp: &p); |
302 | nr = simple_strtoul(p, &p, 0); |
303 | cmm_skip_blanks(cp: p, endp: &p); |
304 | seconds = simple_strtoul(p, &p, 0); |
305 | cmm_set_timeout(nr, seconds); |
306 | *ppos += *lenp; |
307 | } else { |
308 | len = sprintf(buf, fmt: "%ld %ld\n" , |
309 | cmm_timeout_pages, cmm_timeout_seconds); |
310 | if (len > *lenp) |
311 | len = *lenp; |
312 | memcpy(buffer, buf, len); |
313 | *lenp = len; |
314 | *ppos += len; |
315 | } |
316 | return 0; |
317 | } |
318 | |
319 | static struct ctl_table cmm_table[] = { |
320 | { |
321 | .procname = "cmm_pages" , |
322 | .mode = 0644, |
323 | .proc_handler = cmm_pages_handler, |
324 | }, |
325 | { |
326 | .procname = "cmm_timed_pages" , |
327 | .mode = 0644, |
328 | .proc_handler = cmm_timed_pages_handler, |
329 | }, |
330 | { |
331 | .procname = "cmm_timeout" , |
332 | .mode = 0644, |
333 | .proc_handler = cmm_timeout_handler, |
334 | }, |
335 | }; |
336 | |
337 | #ifdef CONFIG_CMM_IUCV |
338 | #define SMSG_PREFIX "CMM" |
339 | static void cmm_smsg_target(const char *from, char *msg) |
340 | { |
341 | long nr, seconds; |
342 | |
343 | if (strlen(sender) > 0 && strcmp(from, sender) != 0) |
344 | return; |
345 | if (!cmm_skip_blanks(msg + strlen(SMSG_PREFIX), &msg)) |
346 | return; |
347 | if (strncmp(msg, "SHRINK" , 6) == 0) { |
348 | if (!cmm_skip_blanks(msg + 6, &msg)) |
349 | return; |
350 | nr = simple_strtoul(msg, &msg, 0); |
351 | cmm_skip_blanks(msg, &msg); |
352 | if (*msg == '\0') |
353 | cmm_set_pages(nr); |
354 | } else if (strncmp(msg, "RELEASE" , 7) == 0) { |
355 | if (!cmm_skip_blanks(msg + 7, &msg)) |
356 | return; |
357 | nr = simple_strtoul(msg, &msg, 0); |
358 | cmm_skip_blanks(msg, &msg); |
359 | if (*msg == '\0') |
360 | cmm_add_timed_pages(nr); |
361 | } else if (strncmp(msg, "REUSE" , 5) == 0) { |
362 | if (!cmm_skip_blanks(msg + 5, &msg)) |
363 | return; |
364 | nr = simple_strtoul(msg, &msg, 0); |
365 | if (!cmm_skip_blanks(msg, &msg)) |
366 | return; |
367 | seconds = simple_strtoul(msg, &msg, 0); |
368 | cmm_skip_blanks(msg, &msg); |
369 | if (*msg == '\0') |
370 | cmm_set_timeout(nr, seconds); |
371 | } |
372 | } |
373 | #endif |
374 | |
375 | static struct ctl_table_header *; |
376 | |
377 | static int __init cmm_init(void) |
378 | { |
379 | int rc = -ENOMEM; |
380 | |
381 | cmm_sysctl_header = register_sysctl("vm" , cmm_table); |
382 | if (!cmm_sysctl_header) |
383 | goto out_sysctl; |
384 | #ifdef CONFIG_CMM_IUCV |
385 | /* convert sender to uppercase characters */ |
386 | if (sender) |
387 | string_upper(sender, sender); |
388 | else |
389 | sender = cmm_default_sender; |
390 | |
391 | rc = smsg_register_callback(SMSG_PREFIX, cmm_smsg_target); |
392 | if (rc < 0) |
393 | goto out_smsg; |
394 | #endif |
395 | rc = register_oom_notifier(nb: &cmm_oom_nb); |
396 | if (rc < 0) |
397 | goto out_oom_notify; |
398 | cmm_thread_ptr = kthread_run(cmm_thread, NULL, "cmmthread" ); |
399 | if (!IS_ERR(ptr: cmm_thread_ptr)) |
400 | return 0; |
401 | |
402 | rc = PTR_ERR(ptr: cmm_thread_ptr); |
403 | unregister_oom_notifier(nb: &cmm_oom_nb); |
404 | out_oom_notify: |
405 | #ifdef CONFIG_CMM_IUCV |
406 | smsg_unregister_callback(SMSG_PREFIX, cmm_smsg_target); |
407 | out_smsg: |
408 | #endif |
409 | unregister_sysctl_table(table: cmm_sysctl_header); |
410 | out_sysctl: |
411 | del_timer_sync(timer: &cmm_timer); |
412 | return rc; |
413 | } |
414 | module_init(cmm_init); |
415 | |
416 | static void __exit cmm_exit(void) |
417 | { |
418 | unregister_sysctl_table(table: cmm_sysctl_header); |
419 | #ifdef CONFIG_CMM_IUCV |
420 | smsg_unregister_callback(SMSG_PREFIX, cmm_smsg_target); |
421 | #endif |
422 | unregister_oom_notifier(nb: &cmm_oom_nb); |
423 | kthread_stop(k: cmm_thread_ptr); |
424 | del_timer_sync(timer: &cmm_timer); |
425 | cmm_free_pages(nr: cmm_pages, counter: &cmm_pages, list: &cmm_page_list); |
426 | cmm_free_pages(nr: cmm_timed_pages, counter: &cmm_timed_pages, list: &cmm_timed_page_list); |
427 | } |
428 | module_exit(cmm_exit); |
429 | |
430 | MODULE_LICENSE("GPL" ); |
431 | |