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>
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>
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
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
;
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
;
98 * cmm_alloc_pages - Allocate pages and mark them as loaned
99 * @nr: number of pages to allocate
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
;
110 cmm_dbg("Begin request for %ld pages\n", nr
);
113 addr
= __get_free_page(GFP_NOIO
| __GFP_NOWARN
|
114 __GFP_NORETRY
| __GFP_NOMEMALLOC
);
117 spin_lock(&cmm_lock
);
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
);
125 pr_info("%s: Can not allocate new page list\n", __func__
);
129 spin_lock(&cmm_lock
);
132 if (!pa
|| pa
->index
>= CMM_NR_PAGES
) {
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
);
148 pa
->page
[pa
->index
++] = addr
;
151 spin_unlock(&cmm_lock
);
155 cmm_dbg("End request with %ld pages unfulfilled\n", nr
);
160 * cmm_free_pages - Free pages and mark them as active
161 * @nr: number of pages to free
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
;
171 cmm_dbg("Begin free of %ld pages.\n", nr
);
172 spin_lock(&cmm_lock
);
175 if (!pa
|| pa
->index
<= 0)
177 addr
= pa
->page
[--pa
->index
];
179 if (pa
->index
== 0) {
181 free_page((unsigned long) cmm_page_list
);
185 plpar_page_set_active(__pa(addr
));
191 spin_unlock(&cmm_lock
);
192 cmm_dbg("End request with %ld pages unfulfilled\n", nr
);
197 * cmm_oom_notify - OOM notifier
198 * @self: notifier block struct
200 * @parm: returned - number of pages freed
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");
221 * cmm_get_mpp - Read memory performance parameters
223 * Makes hcall to query the current page loan request from the hypervisor.
228 static void cmm_get_mpp(void)
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
);
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
)
247 if (target
> oom_freed_pages
)
248 target
-= oom_freed_pages
;
252 active_pages_target
= total_pages
- target
;
254 if (min_mem_pages
> active_pages_target
)
255 target
= total_pages
- min_mem_pages
;
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
278 static int cmm_thread(void *dummy
)
280 unsigned long timeleft
;
283 timeleft
= msleep_interruptible(delay
* 1000);
285 if (kthread_should_stop() || timeleft
) {
286 loaned_pages_target
= loaned_pages
;
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
);
301 #define CMM_SHOW(name, format, args...) \
302 static ssize_t show_##name(struct sys_device *dev, \
303 struct sysdev_attribute *attr, \
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
))
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
[] = {
339 &attr_loaned_target_kb
,
343 static struct sysdev_class cmm_sysdev_class
= {
348 * cmm_sysfs_register - Register with sysfs
351 * 0 on success / other on failure
353 static int cmm_sysfs_register(struct sys_device
*sysdev
)
357 if ((rc
= sysdev_class_register(&cmm_sysdev_class
)))
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
])))
375 sysdev_remove_file(sysdev
, cmm_attrs
[i
]);
376 sysdev_unregister(sysdev
);
378 sysdev_class_unregister(&cmm_sysdev_class
);
383 * cmm_unregister_sysfs - Unregister from sysfs
386 static void cmm_unregister_sysfs(struct sys_device
*sysdev
)
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
) {
405 kthread_stop(cmm_thread_ptr
);
406 cmm_thread_ptr
= NULL
;
407 cmm_free_pages(loaned_pages
);
412 static struct notifier_block cmm_reboot_nb
= {
413 .notifier_call
= cmm_reboot_notifier
,
417 * cmm_init - Module initialization
420 * 0 on success / other on failure
422 static int cmm_init(void)
426 if (!firmware_has_feature(FW_FEATURE_CMO
))
429 if ((rc
= register_oom_notifier(&cmm_oom_nb
)) < 0)
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
;
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
;
449 out_unregister_sysfs
:
450 cmm_unregister_sysfs(&cmm_sysdev
);
452 unregister_reboot_notifier(&cmm_reboot_nb
);
454 unregister_oom_notifier(&cmm_oom_nb
);
459 * cmm_exit - Module exit
464 static void cmm_exit(void)
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
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)
487 if (disable
&& !cmm_disabled
) {
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
;
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
);