2 * Copyright (c) 2012, Microsoft Corporation.
5 * K. Y. Srinivasan <kys@microsoft.com>
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License version 2 as published
9 * by the Free Software Foundation.
11 * This program is distributed in the hope that it will be useful, but
12 * WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
14 * NON INFRINGEMENT. See the GNU General Public License for more
19 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
21 #include <linux/kernel.h>
22 #include <linux/mman.h>
23 #include <linux/delay.h>
24 #include <linux/init.h>
25 #include <linux/module.h>
26 #include <linux/slab.h>
27 #include <linux/kthread.h>
28 #include <linux/completion.h>
29 #include <linux/memory_hotplug.h>
30 #include <linux/memory.h>
31 #include <linux/notifier.h>
32 #include <linux/percpu_counter.h>
34 #include <linux/hyperv.h>
37 * We begin with definitions supporting the Dynamic Memory protocol
40 * Begin protocol definitions.
46 * Protocol versions. The low word is the minor version, the high word the major
51 * Changed to 0.1 on 2009/03/25
52 * Changes to 0.2 on 2009/05/14
53 * Changes to 0.3 on 2009/12/03
54 * Changed to 1.0 on 2011/04/05
57 #define DYNMEM_MAKE_VERSION(Major, Minor) ((__u32)(((Major) << 16) | (Minor)))
58 #define DYNMEM_MAJOR_VERSION(Version) ((__u32)(Version) >> 16)
59 #define DYNMEM_MINOR_VERSION(Version) ((__u32)(Version) & 0xff)
62 DYNMEM_PROTOCOL_VERSION_1
= DYNMEM_MAKE_VERSION(0, 3),
63 DYNMEM_PROTOCOL_VERSION_2
= DYNMEM_MAKE_VERSION(1, 0),
65 DYNMEM_PROTOCOL_VERSION_WIN7
= DYNMEM_PROTOCOL_VERSION_1
,
66 DYNMEM_PROTOCOL_VERSION_WIN8
= DYNMEM_PROTOCOL_VERSION_2
,
68 DYNMEM_PROTOCOL_VERSION_CURRENT
= DYNMEM_PROTOCOL_VERSION_WIN8
77 enum dm_message_type
{
82 DM_VERSION_REQUEST
= 1,
83 DM_VERSION_RESPONSE
= 2,
84 DM_CAPABILITIES_REPORT
= 3,
85 DM_CAPABILITIES_RESPONSE
= 4,
87 DM_BALLOON_REQUEST
= 6,
88 DM_BALLOON_RESPONSE
= 7,
89 DM_UNBALLOON_REQUEST
= 8,
90 DM_UNBALLOON_RESPONSE
= 9,
91 DM_MEM_HOT_ADD_REQUEST
= 10,
92 DM_MEM_HOT_ADD_RESPONSE
= 11,
93 DM_VERSION_03_MAX
= 11,
103 * Structures defining the dynamic memory management
125 union dm_mem_page_range
{
128 * The PFN number of the first page in the range.
129 * 40 bits is the architectural limit of a PFN
134 * The number of pages in the range.
144 * The header for all dynamic memory messages:
146 * type: Type of the message.
147 * size: Size of the message in bytes; including the header.
148 * trans_id: The guest is responsible for manufacturing this ID.
158 * A generic message format for dynamic memory.
159 * Specific message formats are defined later in the file.
163 struct dm_header hdr
;
164 __u8 data
[]; /* enclosed message */
169 * Specific message types supporting the dynamic memory protocol.
173 * Version negotiation message. Sent from the guest to the host.
174 * The guest is free to try different versions until the host
175 * accepts the version.
177 * dm_version: The protocol version requested.
178 * is_last_attempt: If TRUE, this is the last version guest will request.
179 * reservedz: Reserved field, set to zero.
182 struct dm_version_request
{
183 struct dm_header hdr
;
184 union dm_version version
;
185 __u32 is_last_attempt
:1;
190 * Version response message; Host to Guest and indicates
191 * if the host has accepted the version sent by the guest.
193 * is_accepted: If TRUE, host has accepted the version and the guest
194 * should proceed to the next stage of the protocol. FALSE indicates that
195 * guest should re-try with a different version.
197 * reservedz: Reserved field, set to zero.
200 struct dm_version_response
{
201 struct dm_header hdr
;
207 * Message reporting capabilities. This is sent from the guest to the
211 struct dm_capabilities
{
212 struct dm_header hdr
;
215 __u64 max_page_number
;
219 * Response to the capabilities message. This is sent from the host to the
220 * guest. This message notifies if the host has accepted the guest's
221 * capabilities. If the host has not accepted, the guest must shutdown
224 * is_accepted: Indicates if the host has accepted guest's capabilities.
225 * reservedz: Must be 0.
228 struct dm_capabilities_resp_msg
{
229 struct dm_header hdr
;
235 * This message is used to report memory pressure from the guest.
236 * This message is not part of any transaction and there is no
237 * response to this message.
239 * num_avail: Available memory in pages.
240 * num_committed: Committed memory in pages.
241 * page_file_size: The accumulated size of all page files
242 * in the system in pages.
243 * zero_free: The nunber of zero and free pages.
244 * page_file_writes: The writes to the page file in pages.
245 * io_diff: An indicator of file cache efficiency or page file activity,
246 * calculated as File Cache Page Fault Count - Page Read Count.
247 * This value is in pages.
249 * Some of these metrics are Windows specific and fortunately
250 * the algorithm on the host side that computes the guest memory
251 * pressure only uses num_committed value.
255 struct dm_header hdr
;
258 __u64 page_file_size
;
260 __u32 page_file_writes
;
266 * Message to ask the guest to allocate memory - balloon up message.
267 * This message is sent from the host to the guest. The guest may not be
268 * able to allocate as much memory as requested.
270 * num_pages: number of pages to allocate.
274 struct dm_header hdr
;
281 * Balloon response message; this message is sent from the guest
282 * to the host in response to the balloon message.
284 * reservedz: Reserved; must be set to zero.
285 * more_pages: If FALSE, this is the last message of the transaction.
286 * if TRUE there will atleast one more message from the guest.
288 * range_count: The number of ranges in the range array.
290 * range_array: An array of page ranges returned to the host.
294 struct dm_balloon_response
{
295 struct dm_header hdr
;
298 __u32 range_count
:31;
299 union dm_mem_page_range range_array
[];
303 * Un-balloon message; this message is sent from the host
304 * to the guest to give guest more memory.
306 * more_pages: If FALSE, this is the last message of the transaction.
307 * if TRUE there will atleast one more message from the guest.
309 * reservedz: Reserved; must be set to zero.
311 * range_count: The number of ranges in the range array.
313 * range_array: An array of page ranges returned to the host.
317 struct dm_unballoon_request
{
318 struct dm_header hdr
;
322 union dm_mem_page_range range_array
[];
326 * Un-balloon response message; this message is sent from the guest
327 * to the host in response to an unballoon request.
331 struct dm_unballoon_response
{
332 struct dm_header hdr
;
337 * Hot add request message. Message sent from the host to the guest.
339 * mem_range: Memory range to hot add.
341 * On Linux we currently don't support this since we cannot hot add
342 * arbitrary granularity of memory.
346 struct dm_header hdr
;
347 union dm_mem_page_range range
;
351 * Hot add response message.
352 * This message is sent by the guest to report the status of a hot add request.
353 * If page_count is less than the requested page count, then the host should
354 * assume all further hot add requests will fail, since this indicates that
355 * the guest has hit an upper physical memory barrier.
357 * Hot adds may also fail due to low resources; in this case, the guest must
358 * not complete this message until the hot add can succeed, and the host must
359 * not send a new hot add request until the response is sent.
360 * If VSC fails to hot add memory DYNMEM_NUMBER_OF_UNSUCCESSFUL_HOTADD_ATTEMPTS
361 * times it fails the request.
364 * page_count: number of pages that were successfully hot added.
366 * result: result of the operation 1: success, 0: failure.
370 struct dm_hot_add_response
{
371 struct dm_header hdr
;
377 * Types of information sent from host to the guest.
381 INFO_TYPE_MAX_PAGE_CNT
= 0,
387 * Header for the information message.
390 struct dm_info_header
{
391 enum dm_info_type type
;
396 * This message is sent from the host to the guest to pass
397 * some relevant information (win8 addition).
400 * info_size: size of the information blob.
401 * info: information blob.
405 struct dm_header hdr
;
412 * End protocol definitions.
416 static bool do_hot_add
;
418 * Delay reporting memory pressure by
419 * the specified number of seconds.
421 static uint pressure_report_delay
= 30;
423 module_param(hot_add
, bool, (S_IRUGO
| S_IWUSR
));
424 MODULE_PARM_DESC(hot_add
, "If set attempt memory hot_add");
426 module_param(pressure_report_delay
, uint
, (S_IRUGO
| S_IWUSR
));
427 MODULE_PARM_DESC(pressure_report_delay
, "Delay in secs in reporting pressure");
428 static atomic_t trans_id
= ATOMIC_INIT(0);
430 static int dm_ring_size
= (5 * PAGE_SIZE
);
433 * Driver specific state.
446 static __u8 recv_buffer
[PAGE_SIZE
];
447 static __u8
*send_buffer
;
448 #define PAGES_IN_2M 512
450 struct hv_dynmem_device
{
451 struct hv_device
*dev
;
452 enum hv_dm_state state
;
453 struct completion host_event
;
454 struct completion config_event
;
457 * Number of pages we have currently ballooned out.
459 unsigned int num_pages_ballooned
;
462 * This thread handles both balloon/hot-add
463 * requests from the host as well as notifying
464 * the host with regards to memory pressure in
467 struct task_struct
*thread
;
470 * We start with the highest version we can support
471 * and downgrade based on the host; we save here the
472 * next version to try.
477 static struct hv_dynmem_device dm_device
;
479 static void hot_add_req(struct hv_dynmem_device
*dm
, struct dm_hot_add
*msg
)
482 struct dm_hot_add_response resp
;
486 pr_info("Memory hot add not supported\n");
489 * Currently we do not support hot add.
490 * Just fail the request.
494 memset(&resp
, 0, sizeof(struct dm_hot_add_response
));
495 resp
.hdr
.type
= DM_MEM_HOT_ADD_RESPONSE
;
496 resp
.hdr
.size
= sizeof(struct dm_hot_add_response
);
497 resp
.hdr
.trans_id
= atomic_inc_return(&trans_id
);
502 dm
->state
= DM_INITIALIZED
;
503 vmbus_sendpacket(dm
->dev
->channel
, &resp
,
504 sizeof(struct dm_hot_add_response
),
506 VM_PKT_DATA_INBAND
, 0);
510 static void process_info(struct hv_dynmem_device
*dm
, struct dm_info_msg
*msg
)
512 struct dm_info_header
*info_hdr
;
514 info_hdr
= (struct dm_info_header
*)msg
->info
;
516 switch (info_hdr
->type
) {
517 case INFO_TYPE_MAX_PAGE_CNT
:
518 pr_info("Received INFO_TYPE_MAX_PAGE_CNT\n");
519 pr_info("Data Size is %d\n", info_hdr
->data_size
);
522 pr_info("Received Unknown type: %d\n", info_hdr
->type
);
526 unsigned long compute_balloon_floor(void)
528 unsigned long min_pages
;
529 #define MB2PAGES(mb) ((mb) << (20 - PAGE_SHIFT))
530 /* Simple continuous piecewiese linear function:
531 * max MiB -> min MiB gradient
542 if (totalram_pages
< MB2PAGES(128))
543 min_pages
= MB2PAGES(8) + (totalram_pages
>> 1);
544 else if (totalram_pages
< MB2PAGES(512))
545 min_pages
= MB2PAGES(40) + (totalram_pages
>> 2);
546 else if (totalram_pages
< MB2PAGES(2048))
547 min_pages
= MB2PAGES(104) + (totalram_pages
>> 3);
549 min_pages
= MB2PAGES(296) + (totalram_pages
>> 5);
555 * Post our status as it relates memory pressure to the
556 * host. Host expects the guests to post this status
557 * periodically at 1 second intervals.
559 * The metrics specified in this protocol are very Windows
560 * specific and so we cook up numbers here to convey our memory
564 static void post_status(struct hv_dynmem_device
*dm
)
566 struct dm_status status
;
569 if (pressure_report_delay
> 0) {
570 --pressure_report_delay
;
574 memset(&status
, 0, sizeof(struct dm_status
));
575 status
.hdr
.type
= DM_STATUS_REPORT
;
576 status
.hdr
.size
= sizeof(struct dm_status
);
577 status
.hdr
.trans_id
= atomic_inc_return(&trans_id
);
580 * The host expects the guest to report free memory.
581 * Further, the host expects the pressure information to
582 * include the ballooned out pages.
583 * For a given amount of memory that we are managing, we
584 * need to compute a floor below which we should not balloon.
585 * Compute this and add it to the pressure report.
587 status
.num_avail
= val
.freeram
;
588 status
.num_committed
= vm_memory_committed() +
589 dm
->num_pages_ballooned
+
590 compute_balloon_floor();
592 vmbus_sendpacket(dm
->dev
->channel
, &status
,
593 sizeof(struct dm_status
),
595 VM_PKT_DATA_INBAND
, 0);
599 static void free_balloon_pages(struct hv_dynmem_device
*dm
,
600 union dm_mem_page_range
*range_array
)
602 int num_pages
= range_array
->finfo
.page_cnt
;
603 __u64 start_frame
= range_array
->finfo
.start_page
;
607 for (i
= 0; i
< num_pages
; i
++) {
608 pg
= pfn_to_page(i
+ start_frame
);
610 dm
->num_pages_ballooned
--;
616 static int alloc_balloon_pages(struct hv_dynmem_device
*dm
, int num_pages
,
617 struct dm_balloon_response
*bl_resp
, int alloc_unit
,
623 if (num_pages
< alloc_unit
)
626 for (i
= 0; (i
* alloc_unit
) < num_pages
; i
++) {
627 if (bl_resp
->hdr
.size
+ sizeof(union dm_mem_page_range
) >
629 return i
* alloc_unit
;
632 * We execute this code in a thread context. Furthermore,
633 * we don't want the kernel to try too hard.
635 pg
= alloc_pages(GFP_HIGHUSER
| __GFP_NORETRY
|
636 __GFP_NOMEMALLOC
| __GFP_NOWARN
,
637 get_order(alloc_unit
<< PAGE_SHIFT
));
641 return i
* alloc_unit
;
645 dm
->num_pages_ballooned
+= alloc_unit
;
647 bl_resp
->range_count
++;
648 bl_resp
->range_array
[i
].finfo
.start_page
=
650 bl_resp
->range_array
[i
].finfo
.page_cnt
= alloc_unit
;
651 bl_resp
->hdr
.size
+= sizeof(union dm_mem_page_range
);
660 static void balloon_up(struct hv_dynmem_device
*dm
, struct dm_balloon
*req
)
662 int num_pages
= req
->num_pages
;
663 int num_ballooned
= 0;
664 struct dm_balloon_response
*bl_resp
;
667 bool alloc_error
= false;
673 * Currently, we only support 4k allocations.
678 bl_resp
= (struct dm_balloon_response
*)send_buffer
;
679 memset(send_buffer
, 0, PAGE_SIZE
);
680 bl_resp
->hdr
.type
= DM_BALLOON_RESPONSE
;
681 bl_resp
->hdr
.trans_id
= atomic_inc_return(&trans_id
);
682 bl_resp
->hdr
.size
= sizeof(struct dm_balloon_response
);
683 bl_resp
->more_pages
= 1;
686 num_pages
-= num_ballooned
;
687 num_ballooned
= alloc_balloon_pages(dm
, num_pages
,
691 if ((alloc_error
) || (num_ballooned
== num_pages
)) {
692 bl_resp
->more_pages
= 0;
694 dm
->state
= DM_INITIALIZED
;
698 * We are pushing a lot of data through the channel;
699 * deal with transient failures caused because of the
700 * lack of space in the ring buffer.
704 ret
= vmbus_sendpacket(dm_device
.dev
->channel
,
708 VM_PKT_DATA_INBAND
, 0);
713 } while (ret
== -EAGAIN
);
717 * Free up the memory we allocatted.
719 pr_info("Balloon response failed\n");
721 for (i
= 0; i
< bl_resp
->range_count
; i
++)
722 free_balloon_pages(dm
,
723 &bl_resp
->range_array
[i
]);
731 static void balloon_down(struct hv_dynmem_device
*dm
,
732 struct dm_unballoon_request
*req
)
734 union dm_mem_page_range
*range_array
= req
->range_array
;
735 int range_count
= req
->range_count
;
736 struct dm_unballoon_response resp
;
739 for (i
= 0; i
< range_count
; i
++)
740 free_balloon_pages(dm
, &range_array
[i
]);
742 if (req
->more_pages
== 1)
745 memset(&resp
, 0, sizeof(struct dm_unballoon_response
));
746 resp
.hdr
.type
= DM_UNBALLOON_RESPONSE
;
747 resp
.hdr
.trans_id
= atomic_inc_return(&trans_id
);
748 resp
.hdr
.size
= sizeof(struct dm_unballoon_response
);
750 vmbus_sendpacket(dm_device
.dev
->channel
, &resp
,
751 sizeof(struct dm_unballoon_response
),
753 VM_PKT_DATA_INBAND
, 0);
755 dm
->state
= DM_INITIALIZED
;
758 static void balloon_onchannelcallback(void *context
);
760 static int dm_thread_func(void *dm_dev
)
762 struct hv_dynmem_device
*dm
= dm_dev
;
764 unsigned long scan_start
;
766 while (!kthread_should_stop()) {
767 t
= wait_for_completion_timeout(&dm_device
.config_event
, 1*HZ
);
769 * The host expects us to post information on the memory
770 * pressure every second.
776 scan_start
= jiffies
;
779 balloon_up(dm
, (struct dm_balloon
*)recv_buffer
);
783 hot_add_req(dm
, (struct dm_hot_add
*)recv_buffer
);
789 if (!time_in_range(jiffies
, scan_start
, scan_start
+ HZ
))
798 static void version_resp(struct hv_dynmem_device
*dm
,
799 struct dm_version_response
*vresp
)
801 struct dm_version_request version_req
;
804 if (vresp
->is_accepted
) {
806 * We are done; wakeup the
807 * context waiting for version
810 complete(&dm
->host_event
);
814 * If there are more versions to try, continue
815 * with negotiations; if not
816 * shutdown the service since we are not able
817 * to negotiate a suitable version number
820 if (dm
->next_version
== 0)
823 dm
->next_version
= 0;
824 memset(&version_req
, 0, sizeof(struct dm_version_request
));
825 version_req
.hdr
.type
= DM_VERSION_REQUEST
;
826 version_req
.hdr
.size
= sizeof(struct dm_version_request
);
827 version_req
.hdr
.trans_id
= atomic_inc_return(&trans_id
);
828 version_req
.version
.version
= DYNMEM_PROTOCOL_VERSION_WIN7
;
829 version_req
.is_last_attempt
= 1;
831 ret
= vmbus_sendpacket(dm
->dev
->channel
, &version_req
,
832 sizeof(struct dm_version_request
),
834 VM_PKT_DATA_INBAND
, 0);
842 dm
->state
= DM_INIT_ERROR
;
843 complete(&dm
->host_event
);
846 static void cap_resp(struct hv_dynmem_device
*dm
,
847 struct dm_capabilities_resp_msg
*cap_resp
)
849 if (!cap_resp
->is_accepted
) {
850 pr_info("Capabilities not accepted by host\n");
851 dm
->state
= DM_INIT_ERROR
;
853 complete(&dm
->host_event
);
856 static void balloon_onchannelcallback(void *context
)
858 struct hv_device
*dev
= context
;
861 struct dm_message
*dm_msg
;
862 struct dm_header
*dm_hdr
;
863 struct hv_dynmem_device
*dm
= hv_get_drvdata(dev
);
865 memset(recv_buffer
, 0, sizeof(recv_buffer
));
866 vmbus_recvpacket(dev
->channel
, recv_buffer
,
867 PAGE_SIZE
, &recvlen
, &requestid
);
870 dm_msg
= (struct dm_message
*)recv_buffer
;
871 dm_hdr
= &dm_msg
->hdr
;
873 switch (dm_hdr
->type
) {
874 case DM_VERSION_RESPONSE
:
876 (struct dm_version_response
*)dm_msg
);
879 case DM_CAPABILITIES_RESPONSE
:
881 (struct dm_capabilities_resp_msg
*)dm_msg
);
884 case DM_BALLOON_REQUEST
:
885 dm
->state
= DM_BALLOON_UP
;
886 complete(&dm
->config_event
);
889 case DM_UNBALLOON_REQUEST
:
890 dm
->state
= DM_BALLOON_DOWN
;
892 (struct dm_unballoon_request
*)recv_buffer
);
895 case DM_MEM_HOT_ADD_REQUEST
:
896 dm
->state
= DM_HOT_ADD
;
897 complete(&dm
->config_event
);
900 case DM_INFO_MESSAGE
:
901 process_info(dm
, (struct dm_info_msg
*)dm_msg
);
905 pr_err("Unhandled message: type: %d\n", dm_hdr
->type
);
912 static int balloon_probe(struct hv_device
*dev
,
913 const struct hv_vmbus_device_id
*dev_id
)
916 struct dm_version_request version_req
;
917 struct dm_capabilities cap_msg
;
919 do_hot_add
= hot_add
;
922 * First allocate a send buffer.
925 send_buffer
= kmalloc(PAGE_SIZE
, GFP_KERNEL
);
929 ret
= vmbus_open(dev
->channel
, dm_ring_size
, dm_ring_size
, NULL
, 0,
930 balloon_onchannelcallback
, dev
);
936 dm_device
.state
= DM_INITIALIZING
;
937 dm_device
.next_version
= DYNMEM_PROTOCOL_VERSION_WIN7
;
938 init_completion(&dm_device
.host_event
);
939 init_completion(&dm_device
.config_event
);
942 kthread_run(dm_thread_func
, &dm_device
, "hv_balloon");
943 if (IS_ERR(dm_device
.thread
)) {
944 ret
= PTR_ERR(dm_device
.thread
);
948 hv_set_drvdata(dev
, &dm_device
);
950 * Initiate the hand shake with the host and negotiate
951 * a version that the host can support. We start with the
952 * highest version number and go down if the host cannot
955 memset(&version_req
, 0, sizeof(struct dm_version_request
));
956 version_req
.hdr
.type
= DM_VERSION_REQUEST
;
957 version_req
.hdr
.size
= sizeof(struct dm_version_request
);
958 version_req
.hdr
.trans_id
= atomic_inc_return(&trans_id
);
959 version_req
.version
.version
= DYNMEM_PROTOCOL_VERSION_WIN8
;
960 version_req
.is_last_attempt
= 0;
962 ret
= vmbus_sendpacket(dev
->channel
, &version_req
,
963 sizeof(struct dm_version_request
),
966 VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED
);
970 t
= wait_for_completion_timeout(&dm_device
.host_event
, 5*HZ
);
977 * If we could not negotiate a compatible version with the host
978 * fail the probe function.
980 if (dm_device
.state
== DM_INIT_ERROR
) {
985 * Now submit our capabilities to the host.
987 memset(&cap_msg
, 0, sizeof(struct dm_capabilities
));
988 cap_msg
.hdr
.type
= DM_CAPABILITIES_REPORT
;
989 cap_msg
.hdr
.size
= sizeof(struct dm_capabilities
);
990 cap_msg
.hdr
.trans_id
= atomic_inc_return(&trans_id
);
992 cap_msg
.caps
.cap_bits
.balloon
= 1;
994 * While we currently don't support hot-add,
995 * we still advertise this capability since the
996 * host requires that guests partcipating in the
997 * dynamic memory protocol support hot add.
999 cap_msg
.caps
.cap_bits
.hot_add
= 1;
1002 * Currently the host does not use these
1003 * values and we set them to what is done in the
1006 cap_msg
.min_page_cnt
= 0;
1007 cap_msg
.max_page_number
= -1;
1009 ret
= vmbus_sendpacket(dev
->channel
, &cap_msg
,
1010 sizeof(struct dm_capabilities
),
1011 (unsigned long)NULL
,
1013 VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED
);
1017 t
= wait_for_completion_timeout(&dm_device
.host_event
, 5*HZ
);
1024 * If the host does not like our capabilities,
1025 * fail the probe function.
1027 if (dm_device
.state
== DM_INIT_ERROR
) {
1032 dm_device
.state
= DM_INITIALIZED
;
1037 kthread_stop(dm_device
.thread
);
1040 vmbus_close(dev
->channel
);
1046 static int balloon_remove(struct hv_device
*dev
)
1048 struct hv_dynmem_device
*dm
= hv_get_drvdata(dev
);
1050 if (dm
->num_pages_ballooned
!= 0)
1051 pr_warn("Ballooned pages: %d\n", dm
->num_pages_ballooned
);
1053 vmbus_close(dev
->channel
);
1054 kthread_stop(dm
->thread
);
1060 static const struct hv_vmbus_device_id id_table
[] = {
1061 /* Dynamic Memory Class ID */
1062 /* 525074DC-8985-46e2-8057-A307DC18A502 */
1067 MODULE_DEVICE_TABLE(vmbus
, id_table
);
1069 static struct hv_driver balloon_drv
= {
1070 .name
= "hv_balloon",
1071 .id_table
= id_table
,
1072 .probe
= balloon_probe
,
1073 .remove
= balloon_remove
,
1076 static int __init
init_balloon_drv(void)
1079 return vmbus_driver_register(&balloon_drv
);
1082 static void exit_balloon_drv(void)
1085 vmbus_driver_unregister(&balloon_drv
);
1088 module_init(init_balloon_drv
);
1089 module_exit(exit_balloon_drv
);
1091 MODULE_DESCRIPTION("Hyper-V Balloon");
1092 MODULE_VERSION(HV_DRV_VERSION
);
1093 MODULE_LICENSE("GPL");