ia64/linux-2.6.18-xen.hg

view drivers/acpi/pci_irq.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 * pci_irq.c - ACPI PCI Interrupt Routing ($Revision: 11 $)
3 *
4 * Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
5 * Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
6 * Copyright (C) 2002 Dominik Brodowski <devel@brodo.de>
7 *
8 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; either version 2 of the License, or (at
13 * your option) any later version.
14 *
15 * This program is distributed in the hope that it will be useful, but
16 * WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 * General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License along
21 * with this program; if not, write to the Free Software Foundation, Inc.,
22 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
23 *
24 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
25 */
28 #include <linux/kernel.h>
29 #include <linux/module.h>
30 #include <linux/init.h>
31 #include <linux/types.h>
32 #include <linux/proc_fs.h>
33 #include <linux/spinlock.h>
34 #include <linux/pm.h>
35 #include <linux/pci.h>
36 #include <linux/acpi.h>
37 #include <acpi/acpi_bus.h>
38 #include <acpi/acpi_drivers.h>
40 #define _COMPONENT ACPI_PCI_COMPONENT
41 ACPI_MODULE_NAME("pci_irq")
43 static struct acpi_prt_list acpi_prt;
44 static DEFINE_SPINLOCK(acpi_prt_lock);
46 /* --------------------------------------------------------------------------
47 PCI IRQ Routing Table (PRT) Support
48 -------------------------------------------------------------------------- */
50 static struct acpi_prt_entry *acpi_pci_irq_find_prt_entry(int segment,
51 int bus,
52 int device, int pin)
53 {
54 struct list_head *node = NULL;
55 struct acpi_prt_entry *entry = NULL;
58 if (!acpi_prt.count)
59 return NULL;
61 /*
62 * Parse through all PRT entries looking for a match on the specified
63 * PCI device's segment, bus, device, and pin (don't care about func).
64 *
65 */
66 spin_lock(&acpi_prt_lock);
67 list_for_each(node, &acpi_prt.entries) {
68 entry = list_entry(node, struct acpi_prt_entry, node);
69 if ((segment == entry->id.segment)
70 && (bus == entry->id.bus)
71 && (device == entry->id.device)
72 && (pin == entry->pin)) {
73 spin_unlock(&acpi_prt_lock);
74 return entry;
75 }
76 }
78 spin_unlock(&acpi_prt_lock);
79 return NULL;
80 }
82 static int
83 acpi_pci_irq_add_entry(acpi_handle handle,
84 int segment, int bus, struct acpi_pci_routing_table *prt)
85 {
86 struct acpi_prt_entry *entry = NULL;
89 if (!prt)
90 return -EINVAL;
92 entry = kmalloc(sizeof(struct acpi_prt_entry), GFP_KERNEL);
93 if (!entry)
94 return -ENOMEM;
95 memset(entry, 0, sizeof(struct acpi_prt_entry));
97 entry->id.segment = segment;
98 entry->id.bus = bus;
99 entry->id.device = (prt->address >> 16) & 0xFFFF;
100 entry->id.function = prt->address & 0xFFFF;
101 entry->pin = prt->pin;
103 /*
104 * Type 1: Dynamic
105 * ---------------
106 * The 'source' field specifies the PCI interrupt link device used to
107 * configure the IRQ assigned to this slot|dev|pin. The 'source_index'
108 * indicates which resource descriptor in the resource template (of
109 * the link device) this interrupt is allocated from.
110 *
111 * NOTE: Don't query the Link Device for IRQ information at this time
112 * because Link Device enumeration may not have occurred yet
113 * (e.g. exists somewhere 'below' this _PRT entry in the ACPI
114 * namespace).
115 */
116 if (prt->source[0]) {
117 acpi_get_handle(handle, prt->source, &entry->link.handle);
118 entry->link.index = prt->source_index;
119 }
120 /*
121 * Type 2: Static
122 * --------------
123 * The 'source' field is NULL, and the 'source_index' field specifies
124 * the IRQ value, which is hardwired to specific interrupt inputs on
125 * the interrupt controller.
126 */
127 else
128 entry->link.index = prt->source_index;
130 ACPI_DEBUG_PRINT_RAW((ACPI_DB_INFO,
131 " %02X:%02X:%02X[%c] -> %s[%d]\n",
132 entry->id.segment, entry->id.bus,
133 entry->id.device, ('A' + entry->pin), prt->source,
134 entry->link.index));
136 spin_lock(&acpi_prt_lock);
137 list_add_tail(&entry->node, &acpi_prt.entries);
138 acpi_prt.count++;
139 spin_unlock(&acpi_prt_lock);
141 return 0;
142 }
144 static void
145 acpi_pci_irq_del_entry(int segment, int bus, struct acpi_prt_entry *entry)
146 {
147 if (segment == entry->id.segment && bus == entry->id.bus) {
148 acpi_prt.count--;
149 list_del(&entry->node);
150 kfree(entry);
151 }
152 }
154 int acpi_pci_irq_add_prt(acpi_handle handle, int segment, int bus)
155 {
156 acpi_status status = AE_OK;
157 char *pathname = NULL;
158 struct acpi_buffer buffer = { 0, NULL };
159 struct acpi_pci_routing_table *prt = NULL;
160 struct acpi_pci_routing_table *entry = NULL;
161 static int first_time = 1;
164 pathname = (char *)kmalloc(ACPI_PATHNAME_MAX, GFP_KERNEL);
165 if (!pathname)
166 return -ENOMEM;
167 memset(pathname, 0, ACPI_PATHNAME_MAX);
169 if (first_time) {
170 acpi_prt.count = 0;
171 INIT_LIST_HEAD(&acpi_prt.entries);
172 first_time = 0;
173 }
175 /*
176 * NOTE: We're given a 'handle' to the _PRT object's parent device
177 * (either a PCI root bridge or PCI-PCI bridge).
178 */
180 buffer.length = ACPI_PATHNAME_MAX;
181 buffer.pointer = pathname;
182 acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
184 printk(KERN_DEBUG "ACPI: PCI Interrupt Routing Table [%s._PRT]\n",
185 pathname);
187 /*
188 * Evaluate this _PRT and add its entries to our global list (acpi_prt).
189 */
191 buffer.length = 0;
192 buffer.pointer = NULL;
193 kfree(pathname);
194 status = acpi_get_irq_routing_table(handle, &buffer);
195 if (status != AE_BUFFER_OVERFLOW) {
196 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PRT [%s]",
197 acpi_format_exception(status)));
198 return -ENODEV;
199 }
201 prt = kmalloc(buffer.length, GFP_KERNEL);
202 if (!prt) {
203 return -ENOMEM;
204 }
205 memset(prt, 0, buffer.length);
206 buffer.pointer = prt;
208 status = acpi_get_irq_routing_table(handle, &buffer);
209 if (ACPI_FAILURE(status)) {
210 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PRT [%s]",
211 acpi_format_exception(status)));
212 kfree(buffer.pointer);
213 return -ENODEV;
214 }
216 entry = prt;
218 while (entry && (entry->length > 0)) {
219 acpi_pci_irq_add_entry(handle, segment, bus, entry);
220 entry = (struct acpi_pci_routing_table *)
221 ((unsigned long)entry + entry->length);
222 }
224 kfree(prt);
226 return 0;
227 }
229 void acpi_pci_irq_del_prt(int segment, int bus)
230 {
231 struct list_head *node = NULL, *n = NULL;
232 struct acpi_prt_entry *entry = NULL;
234 if (!acpi_prt.count) {
235 return;
236 }
238 printk(KERN_DEBUG
239 "ACPI: Delete PCI Interrupt Routing Table for %x:%x\n", segment,
240 bus);
241 spin_lock(&acpi_prt_lock);
242 list_for_each_safe(node, n, &acpi_prt.entries) {
243 entry = list_entry(node, struct acpi_prt_entry, node);
245 acpi_pci_irq_del_entry(segment, bus, entry);
246 }
247 spin_unlock(&acpi_prt_lock);
248 }
250 /* --------------------------------------------------------------------------
251 PCI Interrupt Routing Support
252 -------------------------------------------------------------------------- */
253 typedef int (*irq_lookup_func) (struct acpi_prt_entry *, int *, int *, char **);
255 static int
256 acpi_pci_allocate_irq(struct acpi_prt_entry *entry,
257 int *triggering, int *polarity, char **link)
258 {
259 int irq;
262 if (entry->link.handle) {
263 irq = acpi_pci_link_allocate_irq(entry->link.handle,
264 entry->link.index, triggering,
265 polarity, link);
266 if (irq < 0) {
267 printk(KERN_WARNING PREFIX
268 "Invalid IRQ link routing entry\n");
269 return -1;
270 }
271 } else {
272 irq = entry->link.index;
273 *triggering = ACPI_LEVEL_SENSITIVE;
274 *polarity = ACPI_ACTIVE_LOW;
275 }
277 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found IRQ %d\n", irq));
278 return irq;
279 }
281 static int
282 acpi_pci_free_irq(struct acpi_prt_entry *entry,
283 int *triggering, int *polarity, char **link)
284 {
285 int irq;
287 if (entry->link.handle) {
288 irq = acpi_pci_link_free_irq(entry->link.handle);
289 } else {
290 irq = entry->link.index;
291 }
292 return irq;
293 }
295 /*
296 * acpi_pci_irq_lookup
297 * success: return IRQ >= 0
298 * failure: return -1
299 */
300 static int
301 acpi_pci_irq_lookup(struct pci_bus *bus,
302 int device,
303 int pin,
304 int *triggering,
305 int *polarity, char **link, irq_lookup_func func)
306 {
307 struct acpi_prt_entry *entry = NULL;
308 int segment = pci_domain_nr(bus);
309 int bus_nr = bus->number;
310 int ret;
313 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
314 "Searching for PRT entry for %02x:%02x:%02x[%c]\n",
315 segment, bus_nr, device, ('A' + pin)));
317 entry = acpi_pci_irq_find_prt_entry(segment, bus_nr, device, pin);
318 if (!entry) {
319 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "PRT entry not found\n"));
320 return -1;
321 }
323 ret = func(entry, triggering, polarity, link);
324 return ret;
325 }
327 /*
328 * acpi_pci_irq_derive
329 * success: return IRQ >= 0
330 * failure: return < 0
331 */
332 static int
333 acpi_pci_irq_derive(struct pci_dev *dev,
334 int pin,
335 int *triggering,
336 int *polarity, char **link, irq_lookup_func func)
337 {
338 struct pci_dev *bridge = dev;
339 int irq = -1;
340 u8 bridge_pin = 0;
343 if (!dev)
344 return -EINVAL;
346 /*
347 * Attempt to derive an IRQ for this device from a parent bridge's
348 * PCI interrupt routing entry (eg. yenta bridge and add-in card bridge).
349 */
350 while (irq < 0 && bridge->bus->self) {
351 pin = (pin + PCI_SLOT(bridge->devfn)) % 4;
352 bridge = bridge->bus->self;
354 if ((bridge->class >> 8) == PCI_CLASS_BRIDGE_CARDBUS) {
355 /* PC card has the same IRQ as its cardbridge */
356 bridge_pin = bridge->pin;
357 if (!bridge_pin) {
358 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
359 "No interrupt pin configured for device %s\n",
360 pci_name(bridge)));
361 return -1;
362 }
363 /* Pin is from 0 to 3 */
364 bridge_pin--;
365 pin = bridge_pin;
366 }
368 irq = acpi_pci_irq_lookup(bridge->bus, PCI_SLOT(bridge->devfn),
369 pin, triggering, polarity,
370 link, func);
371 }
373 if (irq < 0) {
374 printk(KERN_WARNING PREFIX "Unable to derive IRQ for device %s\n",
375 pci_name(dev));
376 return -1;
377 }
379 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Derive IRQ %d for device %s from %s\n",
380 irq, pci_name(dev), pci_name(bridge)));
382 return irq;
383 }
385 /*
386 * acpi_pci_irq_enable
387 * success: return 0
388 * failure: return < 0
389 */
391 int acpi_pci_irq_enable(struct pci_dev *dev)
392 {
393 int irq = 0;
394 u8 pin = 0;
395 int triggering = ACPI_LEVEL_SENSITIVE;
396 int polarity = ACPI_ACTIVE_LOW;
397 char *link = NULL;
398 int rc;
401 if (!dev)
402 return -EINVAL;
404 pin = dev->pin;
405 if (!pin) {
406 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
407 "No interrupt pin configured for device %s\n",
408 pci_name(dev)));
409 return 0;
410 }
411 pin--;
413 if (!dev->bus) {
414 printk(KERN_ERR PREFIX "Invalid (NULL) 'bus' field\n");
415 return -ENODEV;
416 }
418 /*
419 * First we check the PCI IRQ routing table (PRT) for an IRQ. PRT
420 * values override any BIOS-assigned IRQs set during boot.
421 */
422 irq = acpi_pci_irq_lookup(dev->bus, PCI_SLOT(dev->devfn), pin,
423 &triggering, &polarity, &link,
424 acpi_pci_allocate_irq);
426 /*
427 * If no PRT entry was found, we'll try to derive an IRQ from the
428 * device's parent bridge.
429 */
430 if (irq < 0)
431 irq = acpi_pci_irq_derive(dev, pin, &triggering,
432 &polarity, &link,
433 acpi_pci_allocate_irq);
435 /*
436 * No IRQ known to the ACPI subsystem - maybe the BIOS /
437 * driver reported one, then use it. Exit in any case.
438 */
439 if (irq < 0) {
440 printk(KERN_WARNING PREFIX "PCI Interrupt %s[%c]: no GSI",
441 pci_name(dev), ('A' + pin));
442 /* Interrupt Line values above 0xF are forbidden */
443 if (dev->irq > 0 && (dev->irq <= 0xF)) {
444 printk(" - using IRQ %d\n", dev->irq);
445 acpi_register_gsi(dev->irq, ACPI_LEVEL_SENSITIVE,
446 ACPI_ACTIVE_LOW);
447 return 0;
448 } else {
449 printk("\n");
450 return 0;
451 }
452 }
454 rc = acpi_register_gsi(irq, triggering, polarity);
455 if (rc < 0) {
456 printk(KERN_WARNING PREFIX "PCI Interrupt %s[%c]: failed "
457 "to register GSI\n", pci_name(dev), ('A' + pin));
458 return rc;
459 }
460 dev->irq = rc;
462 printk(KERN_INFO PREFIX "PCI Interrupt %s[%c] -> ",
463 pci_name(dev), 'A' + pin);
465 if (link)
466 printk("Link [%s] -> ", link);
468 printk("GSI %u (%s, %s) -> IRQ %d\n", irq,
469 (triggering == ACPI_LEVEL_SENSITIVE) ? "level" : "edge",
470 (polarity == ACPI_ACTIVE_LOW) ? "low" : "high", dev->irq);
472 return 0;
473 }
475 EXPORT_SYMBOL(acpi_pci_irq_enable);
477 /* FIXME: implement x86/x86_64 version */
478 void __attribute__ ((weak)) acpi_unregister_gsi(u32 i)
479 {
480 }
482 void acpi_pci_irq_disable(struct pci_dev *dev)
483 {
484 int gsi = 0;
485 u8 pin = 0;
486 int triggering = ACPI_LEVEL_SENSITIVE;
487 int polarity = ACPI_ACTIVE_LOW;
490 if (!dev || !dev->bus)
491 return;
493 pin = dev->pin;
494 if (!pin)
495 return;
496 pin--;
498 /*
499 * First we check the PCI IRQ routing table (PRT) for an IRQ.
500 */
501 gsi = acpi_pci_irq_lookup(dev->bus, PCI_SLOT(dev->devfn), pin,
502 &triggering, &polarity, NULL,
503 acpi_pci_free_irq);
504 /*
505 * If no PRT entry was found, we'll try to derive an IRQ from the
506 * device's parent bridge.
507 */
508 if (gsi < 0)
509 gsi = acpi_pci_irq_derive(dev, pin,
510 &triggering, &polarity, NULL,
511 acpi_pci_free_irq);
512 if (gsi < 0)
513 return;
515 /*
516 * TBD: It might be worth clearing dev->irq by magic constant
517 * (e.g. PCI_UNDEFINED_IRQ).
518 */
520 printk(KERN_INFO PREFIX "PCI interrupt for device %s disabled\n",
521 pci_name(dev));
523 acpi_unregister_gsi(gsi);
525 return;
526 }