ia64/linux-2.6.18-xen.hg

view drivers/acpi/namespace/nsobject.c @ 897:329ea0ccb344

balloon: try harder to balloon up under memory pressure.

Currently if the balloon driver is unable to increase the guest's
reservation it assumes the failure was due to reaching its full
allocation, gives up on the ballooning operation and records the limit
it reached as the "hard limit". The driver will not try again until
the target is set again (even to the same value).

However it is possible that ballooning has in fact failed due to
memory pressure in the host and therefore it is desirable to keep
attempting to reach the target in case memory becomes available. The
most likely scenario is that some guests are ballooning down while
others are ballooning up and therefore there is temporary memory
pressure while things stabilise. You would not expect a well behaved
toolstack to ask a domain to balloon to more than its allocation nor
would you expect it to deliberately over-commit memory by setting
balloon targets which exceed the total host memory.

This patch drops the concept of a hard limit and causes the balloon
driver to retry increasing the reservation on a timer in the same
manner as when decreasing the reservation.

Also if we partially succeed in increasing the reservation
(i.e. receive less pages than we asked for) then we may as well keep
those pages rather than returning them to Xen.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
author Keir Fraser <keir.fraser@citrix.com>
date Fri Jun 05 14:01:20 2009 +0100 (2009-06-05)
parents 831230e53067
children
line source
1 /*******************************************************************************
2 *
3 * Module Name: nsobject - Utilities for objects attached to namespace
4 * table entries
5 *
6 ******************************************************************************/
8 /*
9 * Copyright (C) 2000 - 2006, R. Byron Moore
10 * All rights reserved.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions, and the following disclaimer,
17 * without modification.
18 * 2. Redistributions in binary form must reproduce at minimum a disclaimer
19 * substantially similar to the "NO WARRANTY" disclaimer below
20 * ("Disclaimer") and any redistribution must be conditioned upon
21 * including a substantially similar Disclaimer requirement for further
22 * binary redistribution.
23 * 3. Neither the names of the above-listed copyright holders nor the names
24 * of any contributors may be used to endorse or promote products derived
25 * from this software without specific prior written permission.
26 *
27 * Alternatively, this software may be distributed under the terms of the
28 * GNU General Public License ("GPL") version 2 as published by the Free
29 * Software Foundation.
30 *
31 * NO WARRANTY
32 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
33 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
34 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
35 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
36 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
37 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
38 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
39 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
40 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
41 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
42 * POSSIBILITY OF SUCH DAMAGES.
43 */
45 #include <acpi/acpi.h>
46 #include <acpi/acnamesp.h>
48 #define _COMPONENT ACPI_NAMESPACE
49 ACPI_MODULE_NAME("nsobject")
51 /*******************************************************************************
52 *
53 * FUNCTION: acpi_ns_attach_object
54 *
55 * PARAMETERS: Node - Parent Node
56 * Object - Object to be attached
57 * Type - Type of object, or ACPI_TYPE_ANY if not
58 * known
59 *
60 * RETURN: Status
61 *
62 * DESCRIPTION: Record the given object as the value associated with the
63 * name whose acpi_handle is passed. If Object is NULL
64 * and Type is ACPI_TYPE_ANY, set the name as having no value.
65 * Note: Future may require that the Node->Flags field be passed
66 * as a parameter.
67 *
68 * MUTEX: Assumes namespace is locked
69 *
70 ******************************************************************************/
71 acpi_status
72 acpi_ns_attach_object(struct acpi_namespace_node *node,
73 union acpi_operand_object *object, acpi_object_type type)
74 {
75 union acpi_operand_object *obj_desc;
76 union acpi_operand_object *last_obj_desc;
77 acpi_object_type object_type = ACPI_TYPE_ANY;
79 ACPI_FUNCTION_TRACE(ns_attach_object);
81 /*
82 * Parameter validation
83 */
84 if (!node) {
86 /* Invalid handle */
88 ACPI_ERROR((AE_INFO, "Null NamedObj handle"));
89 return_ACPI_STATUS(AE_BAD_PARAMETER);
90 }
92 if (!object && (ACPI_TYPE_ANY != type)) {
94 /* Null object */
96 ACPI_ERROR((AE_INFO,
97 "Null object, but type not ACPI_TYPE_ANY"));
98 return_ACPI_STATUS(AE_BAD_PARAMETER);
99 }
101 if (ACPI_GET_DESCRIPTOR_TYPE(node) != ACPI_DESC_TYPE_NAMED) {
103 /* Not a name handle */
105 ACPI_ERROR((AE_INFO, "Invalid handle %p [%s]",
106 node, acpi_ut_get_descriptor_name(node)));
107 return_ACPI_STATUS(AE_BAD_PARAMETER);
108 }
110 /* Check if this object is already attached */
112 if (node->object == object) {
113 ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
114 "Obj %p already installed in NameObj %p\n",
115 object, node));
117 return_ACPI_STATUS(AE_OK);
118 }
120 /* If null object, we will just install it */
122 if (!object) {
123 obj_desc = NULL;
124 object_type = ACPI_TYPE_ANY;
125 }
127 /*
128 * If the source object is a namespace Node with an attached object,
129 * we will use that (attached) object
130 */
131 else if ((ACPI_GET_DESCRIPTOR_TYPE(object) == ACPI_DESC_TYPE_NAMED) &&
132 ((struct acpi_namespace_node *)object)->object) {
133 /*
134 * Value passed is a name handle and that name has a
135 * non-null value. Use that name's value and type.
136 */
137 obj_desc = ((struct acpi_namespace_node *)object)->object;
138 object_type = ((struct acpi_namespace_node *)object)->type;
139 }
141 /*
142 * Otherwise, we will use the parameter object, but we must type
143 * it first
144 */
145 else {
146 obj_desc = (union acpi_operand_object *)object;
148 /* Use the given type */
150 object_type = type;
151 }
153 ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "Installing %p into Node %p [%4.4s]\n",
154 obj_desc, node, acpi_ut_get_node_name(node)));
156 /* Detach an existing attached object if present */
158 if (node->object) {
159 acpi_ns_detach_object(node);
160 }
162 if (obj_desc) {
163 /*
164 * Must increment the new value's reference count
165 * (if it is an internal object)
166 */
167 acpi_ut_add_reference(obj_desc);
169 /*
170 * Handle objects with multiple descriptors - walk
171 * to the end of the descriptor list
172 */
173 last_obj_desc = obj_desc;
174 while (last_obj_desc->common.next_object) {
175 last_obj_desc = last_obj_desc->common.next_object;
176 }
178 /* Install the object at the front of the object list */
180 last_obj_desc->common.next_object = node->object;
181 }
183 node->type = (u8) object_type;
184 node->object = obj_desc;
186 return_ACPI_STATUS(AE_OK);
187 }
189 /*******************************************************************************
190 *
191 * FUNCTION: acpi_ns_detach_object
192 *
193 * PARAMETERS: Node - A Namespace node whose object will be detached
194 *
195 * RETURN: None.
196 *
197 * DESCRIPTION: Detach/delete an object associated with a namespace node.
198 * if the object is an allocated object, it is freed.
199 * Otherwise, the field is simply cleared.
200 *
201 ******************************************************************************/
203 void acpi_ns_detach_object(struct acpi_namespace_node *node)
204 {
205 union acpi_operand_object *obj_desc;
207 ACPI_FUNCTION_TRACE(ns_detach_object);
209 obj_desc = node->object;
211 if (!obj_desc ||
212 (ACPI_GET_OBJECT_TYPE(obj_desc) == ACPI_TYPE_LOCAL_DATA)) {
213 return_VOID;
214 }
216 /* Clear the entry in all cases */
218 node->object = NULL;
219 if (ACPI_GET_DESCRIPTOR_TYPE(obj_desc) == ACPI_DESC_TYPE_OPERAND) {
220 node->object = obj_desc->common.next_object;
221 if (node->object &&
222 (ACPI_GET_OBJECT_TYPE(node->object) !=
223 ACPI_TYPE_LOCAL_DATA)) {
224 node->object = node->object->common.next_object;
225 }
226 }
228 /* Reset the node type to untyped */
230 node->type = ACPI_TYPE_ANY;
232 ACPI_DEBUG_PRINT((ACPI_DB_NAMES, "Node %p [%4.4s] Object %p\n",
233 node, acpi_ut_get_node_name(node), obj_desc));
235 /* Remove one reference on the object (and all subobjects) */
237 acpi_ut_remove_reference(obj_desc);
238 return_VOID;
239 }
241 /*******************************************************************************
242 *
243 * FUNCTION: acpi_ns_get_attached_object
244 *
245 * PARAMETERS: Node - Namespace node
246 *
247 * RETURN: Current value of the object field from the Node whose
248 * handle is passed
249 *
250 * DESCRIPTION: Obtain the object attached to a namespace node.
251 *
252 ******************************************************************************/
254 union acpi_operand_object *acpi_ns_get_attached_object(struct
255 acpi_namespace_node
256 *node)
257 {
258 ACPI_FUNCTION_TRACE_PTR(ns_get_attached_object, node);
260 if (!node) {
261 ACPI_WARNING((AE_INFO, "Null Node ptr"));
262 return_PTR(NULL);
263 }
265 if (!node->object ||
266 ((ACPI_GET_DESCRIPTOR_TYPE(node->object) != ACPI_DESC_TYPE_OPERAND)
267 && (ACPI_GET_DESCRIPTOR_TYPE(node->object) !=
268 ACPI_DESC_TYPE_NAMED))
269 || (ACPI_GET_OBJECT_TYPE(node->object) == ACPI_TYPE_LOCAL_DATA)) {
270 return_PTR(NULL);
271 }
273 return_PTR(node->object);
274 }
276 /*******************************************************************************
277 *
278 * FUNCTION: acpi_ns_get_secondary_object
279 *
280 * PARAMETERS: Node - Namespace node
281 *
282 * RETURN: Current value of the object field from the Node whose
283 * handle is passed.
284 *
285 * DESCRIPTION: Obtain a secondary object associated with a namespace node.
286 *
287 ******************************************************************************/
289 union acpi_operand_object *acpi_ns_get_secondary_object(union
290 acpi_operand_object
291 *obj_desc)
292 {
293 ACPI_FUNCTION_TRACE_PTR(ns_get_secondary_object, obj_desc);
295 if ((!obj_desc) ||
296 (ACPI_GET_OBJECT_TYPE(obj_desc) == ACPI_TYPE_LOCAL_DATA) ||
297 (!obj_desc->common.next_object) ||
298 (ACPI_GET_OBJECT_TYPE(obj_desc->common.next_object) ==
299 ACPI_TYPE_LOCAL_DATA)) {
300 return_PTR(NULL);
301 }
303 return_PTR(obj_desc->common.next_object);
304 }
306 /*******************************************************************************
307 *
308 * FUNCTION: acpi_ns_attach_data
309 *
310 * PARAMETERS: Node - Namespace node
311 * Handler - Handler to be associated with the data
312 * Data - Data to be attached
313 *
314 * RETURN: Status
315 *
316 * DESCRIPTION: Low-level attach data. Create and attach a Data object.
317 *
318 ******************************************************************************/
320 acpi_status
321 acpi_ns_attach_data(struct acpi_namespace_node *node,
322 acpi_object_handler handler, void *data)
323 {
324 union acpi_operand_object *prev_obj_desc;
325 union acpi_operand_object *obj_desc;
326 union acpi_operand_object *data_desc;
328 /* We only allow one attachment per handler */
330 prev_obj_desc = NULL;
331 obj_desc = node->object;
332 while (obj_desc) {
333 if ((ACPI_GET_OBJECT_TYPE(obj_desc) == ACPI_TYPE_LOCAL_DATA) &&
334 (obj_desc->data.handler == handler)) {
335 return (AE_ALREADY_EXISTS);
336 }
338 prev_obj_desc = obj_desc;
339 obj_desc = obj_desc->common.next_object;
340 }
342 /* Create an internal object for the data */
344 data_desc = acpi_ut_create_internal_object(ACPI_TYPE_LOCAL_DATA);
345 if (!data_desc) {
346 return (AE_NO_MEMORY);
347 }
349 data_desc->data.handler = handler;
350 data_desc->data.pointer = data;
352 /* Install the data object */
354 if (prev_obj_desc) {
355 prev_obj_desc->common.next_object = data_desc;
356 } else {
357 node->object = data_desc;
358 }
360 return (AE_OK);
361 }
363 /*******************************************************************************
364 *
365 * FUNCTION: acpi_ns_detach_data
366 *
367 * PARAMETERS: Node - Namespace node
368 * Handler - Handler associated with the data
369 *
370 * RETURN: Status
371 *
372 * DESCRIPTION: Low-level detach data. Delete the data node, but the caller
373 * is responsible for the actual data.
374 *
375 ******************************************************************************/
377 acpi_status
378 acpi_ns_detach_data(struct acpi_namespace_node * node,
379 acpi_object_handler handler)
380 {
381 union acpi_operand_object *obj_desc;
382 union acpi_operand_object *prev_obj_desc;
384 prev_obj_desc = NULL;
385 obj_desc = node->object;
386 while (obj_desc) {
387 if ((ACPI_GET_OBJECT_TYPE(obj_desc) == ACPI_TYPE_LOCAL_DATA) &&
388 (obj_desc->data.handler == handler)) {
389 if (prev_obj_desc) {
390 prev_obj_desc->common.next_object =
391 obj_desc->common.next_object;
392 } else {
393 node->object = obj_desc->common.next_object;
394 }
396 acpi_ut_remove_reference(obj_desc);
397 return (AE_OK);
398 }
400 prev_obj_desc = obj_desc;
401 obj_desc = obj_desc->common.next_object;
402 }
404 return (AE_NOT_FOUND);
405 }
407 /*******************************************************************************
408 *
409 * FUNCTION: acpi_ns_get_attached_data
410 *
411 * PARAMETERS: Node - Namespace node
412 * Handler - Handler associated with the data
413 * Data - Where the data is returned
414 *
415 * RETURN: Status
416 *
417 * DESCRIPTION: Low level interface to obtain data previously associated with
418 * a namespace node.
419 *
420 ******************************************************************************/
422 acpi_status
423 acpi_ns_get_attached_data(struct acpi_namespace_node * node,
424 acpi_object_handler handler, void **data)
425 {
426 union acpi_operand_object *obj_desc;
428 obj_desc = node->object;
429 while (obj_desc) {
430 if ((ACPI_GET_OBJECT_TYPE(obj_desc) == ACPI_TYPE_LOCAL_DATA) &&
431 (obj_desc->data.handler == handler)) {
432 *data = obj_desc->data.pointer;
433 return (AE_OK);
434 }
436 obj_desc = obj_desc->common.next_object;
437 }
439 return (AE_NOT_FOUND);
440 }