11775826cSJeremy Fitzhardinge /******************************************************************************
21775826cSJeremy Fitzhardinge * Xen balloon driver - enables returning/claiming memory to/from Xen.
31775826cSJeremy Fitzhardinge *
41775826cSJeremy Fitzhardinge * Copyright (c) 2003, B Dragovic
51775826cSJeremy Fitzhardinge * Copyright (c) 2003-2004, M Williamson, K Fraser
61775826cSJeremy Fitzhardinge * Copyright (c) 2005 Dan M. Smith, IBM Corporation
7080e2be7SDaniel Kiper * Copyright (c) 2010 Daniel Kiper
8080e2be7SDaniel Kiper *
9080e2be7SDaniel Kiper * Memory hotplug support was written by Daniel Kiper. Work on
10080e2be7SDaniel Kiper * it was sponsored by Google under Google Summer of Code 2010
11080e2be7SDaniel Kiper * program. Jeremy Fitzhardinge from Citrix was the mentor for
12080e2be7SDaniel Kiper * this project.
131775826cSJeremy Fitzhardinge *
141775826cSJeremy Fitzhardinge * This program is free software; you can redistribute it and/or
151775826cSJeremy Fitzhardinge * modify it under the terms of the GNU General Public License version 2
161775826cSJeremy Fitzhardinge * as published by the Free Software Foundation; or, when distributed
171775826cSJeremy Fitzhardinge * separately from the Linux kernel or incorporated into other
181775826cSJeremy Fitzhardinge * software packages, subject to the following license:
191775826cSJeremy Fitzhardinge *
201775826cSJeremy Fitzhardinge * Permission is hereby granted, free of charge, to any person obtaining a copy
211775826cSJeremy Fitzhardinge * of this source file (the "Software"), to deal in the Software without
221775826cSJeremy Fitzhardinge * restriction, including without limitation the rights to use, copy, modify,
231775826cSJeremy Fitzhardinge * merge, publish, distribute, sublicense, and/or sell copies of the Software,
241775826cSJeremy Fitzhardinge * and to permit persons to whom the Software is furnished to do so, subject to
251775826cSJeremy Fitzhardinge * the following conditions:
261775826cSJeremy Fitzhardinge *
271775826cSJeremy Fitzhardinge * The above copyright notice and this permission notice shall be included in
281775826cSJeremy Fitzhardinge * all copies or substantial portions of the Software.
291775826cSJeremy Fitzhardinge *
301775826cSJeremy Fitzhardinge * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
311775826cSJeremy Fitzhardinge * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
321775826cSJeremy Fitzhardinge * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
331775826cSJeremy Fitzhardinge * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
341775826cSJeremy Fitzhardinge * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
351775826cSJeremy Fitzhardinge * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
361775826cSJeremy Fitzhardinge * IN THE SOFTWARE.
371775826cSJeremy Fitzhardinge */
381775826cSJeremy Fitzhardinge
39283c0972SJoe Perches #define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt
40283c0972SJoe Perches
41cd9151e2SStefano Stabellini #include <linux/cpu.h>
421775826cSJeremy Fitzhardinge #include <linux/kernel.h>
431775826cSJeremy Fitzhardinge #include <linux/sched.h>
445b825c3aSIngo Molnar #include <linux/cred.h>
451775826cSJeremy Fitzhardinge #include <linux/errno.h>
468480ed9cSJuergen Gross #include <linux/freezer.h>
478480ed9cSJuergen Gross #include <linux/kthread.h>
481775826cSJeremy Fitzhardinge #include <linux/mm.h>
4957c8a661SMike Rapoport #include <linux/memblock.h>
501775826cSJeremy Fitzhardinge #include <linux/pagemap.h>
511775826cSJeremy Fitzhardinge #include <linux/highmem.h>
521775826cSJeremy Fitzhardinge #include <linux/mutex.h>
531775826cSJeremy Fitzhardinge #include <linux/list.h>
545a0e3ad6STejun Heo #include <linux/gfp.h>
55080e2be7SDaniel Kiper #include <linux/notifier.h>
56080e2be7SDaniel Kiper #include <linux/memory.h>
57080e2be7SDaniel Kiper #include <linux/memory_hotplug.h>
58cd9151e2SStefano Stabellini #include <linux/percpu-defs.h>
5955b3da98SDavid Vrabel #include <linux/slab.h>
601cf6a6c8SDavid Vrabel #include <linux/sysctl.h>
6140fdea02SJuergen Gross #include <linux/moduleparam.h>
62b537bf42SWang Qing #include <linux/jiffies.h>
631775826cSJeremy Fitzhardinge
641775826cSJeremy Fitzhardinge #include <asm/page.h>
651775826cSJeremy Fitzhardinge #include <asm/tlb.h>
661775826cSJeremy Fitzhardinge
67ecbf29cdSJeremy Fitzhardinge #include <asm/xen/hypervisor.h>
68ecbf29cdSJeremy Fitzhardinge #include <asm/xen/hypercall.h>
691ccbf534SJeremy Fitzhardinge
701ccbf534SJeremy Fitzhardinge #include <xen/xen.h>
71ecbf29cdSJeremy Fitzhardinge #include <xen/interface/xen.h>
721775826cSJeremy Fitzhardinge #include <xen/interface/memory.h>
73803eb047SDaniel De Graaf #include <xen/balloon.h>
741775826cSJeremy Fitzhardinge #include <xen/features.h>
751775826cSJeremy Fitzhardinge #include <xen/page.h>
76ae4c51a5SOleksandr Andrushchenko #include <xen/mem-reservation.h>
771775826cSJeremy Fitzhardinge
7840fdea02SJuergen Gross #undef MODULE_PARAM_PREFIX
7940fdea02SJuergen Gross #define MODULE_PARAM_PREFIX "xen."
8040fdea02SJuergen Gross
8140fdea02SJuergen Gross static uint __read_mostly balloon_boot_timeout = 180;
8240fdea02SJuergen Gross module_param(balloon_boot_timeout, uint, 0444);
8340fdea02SJuergen Gross
841cf6a6c8SDavid Vrabel #ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
85501586eaSArnd Bergmann static int xen_hotplug_unpopulated;
861cf6a6c8SDavid Vrabel
871cf6a6c8SDavid Vrabel static struct ctl_table balloon_table[] = {
881cf6a6c8SDavid Vrabel {
891cf6a6c8SDavid Vrabel .procname = "hotplug_unpopulated",
901cf6a6c8SDavid Vrabel .data = &xen_hotplug_unpopulated,
911cf6a6c8SDavid Vrabel .maxlen = sizeof(int),
921cf6a6c8SDavid Vrabel .mode = 0644,
931cf6a6c8SDavid Vrabel .proc_handler = proc_dointvec_minmax,
94eec4844fSMatteo Croce .extra1 = SYSCTL_ZERO,
95eec4844fSMatteo Croce .extra2 = SYSCTL_ONE,
961cf6a6c8SDavid Vrabel },
971cf6a6c8SDavid Vrabel { }
981cf6a6c8SDavid Vrabel };
991cf6a6c8SDavid Vrabel
100501586eaSArnd Bergmann #else
101501586eaSArnd Bergmann #define xen_hotplug_unpopulated 0
1021cf6a6c8SDavid Vrabel #endif
1031cf6a6c8SDavid Vrabel
1041775826cSJeremy Fitzhardinge /*
10530756c62SJulien Grall * Use one extent per PAGE_SIZE to avoid to break down the page into
10630756c62SJulien Grall * multiple frame.
10730756c62SJulien Grall */
10830756c62SJulien Grall #define EXTENT_ORDER (fls(XEN_PFN_PER_PAGE) - 1)
10930756c62SJulien Grall
11030756c62SJulien Grall /*
1118480ed9cSJuergen Gross * balloon_thread() state:
11295d2ac4aSDaniel Kiper *
11395d2ac4aSDaniel Kiper * BP_DONE: done or nothing to do,
114b2ac6aa8SDavid Vrabel * BP_WAIT: wait to be rescheduled,
11595d2ac4aSDaniel Kiper * BP_EAGAIN: error, go to sleep,
11695d2ac4aSDaniel Kiper * BP_ECANCELED: error, balloon operation canceled.
1171775826cSJeremy Fitzhardinge */
11895d2ac4aSDaniel Kiper
11940fdea02SJuergen Gross static enum bp_state {
12095d2ac4aSDaniel Kiper BP_DONE,
121b2ac6aa8SDavid Vrabel BP_WAIT,
12295d2ac4aSDaniel Kiper BP_EAGAIN,
12395d2ac4aSDaniel Kiper BP_ECANCELED
12440fdea02SJuergen Gross } balloon_state = BP_DONE;
1251775826cSJeremy Fitzhardinge
1268480ed9cSJuergen Gross /* Main waiting point for xen-balloon thread. */
1278480ed9cSJuergen Gross static DECLARE_WAIT_QUEUE_HEAD(balloon_thread_wq);
1281775826cSJeremy Fitzhardinge
1291775826cSJeremy Fitzhardinge static DEFINE_MUTEX(balloon_mutex);
1301775826cSJeremy Fitzhardinge
131803eb047SDaniel De Graaf struct balloon_stats balloon_stats;
132803eb047SDaniel De Graaf EXPORT_SYMBOL_GPL(balloon_stats);
1331775826cSJeremy Fitzhardinge
1341775826cSJeremy Fitzhardinge /* We increase/decrease in batches which fit in a page */
1353990dd27SJulien Grall static xen_pfn_t frame_list[PAGE_SIZE / sizeof(xen_pfn_t)];
136cd9151e2SStefano Stabellini
1371775826cSJeremy Fitzhardinge
1381775826cSJeremy Fitzhardinge /* List of ballooned pages, threaded through the mem_map array. */
1391775826cSJeremy Fitzhardinge static LIST_HEAD(ballooned_pages);
1401cf6a6c8SDavid Vrabel static DECLARE_WAIT_QUEUE_HEAD(balloon_wq);
1411775826cSJeremy Fitzhardinge
1421775826cSJeremy Fitzhardinge /* When ballooning out (allocating memory to return to Xen) we don't really
1431775826cSJeremy Fitzhardinge want the kernel to try too hard since that can trigger the oom killer. */
1441775826cSJeremy Fitzhardinge #define GFP_BALLOON \
1451775826cSJeremy Fitzhardinge (GFP_HIGHUSER | __GFP_NOWARN | __GFP_NORETRY | __GFP_NOMEMALLOC)
1461775826cSJeremy Fitzhardinge
1471775826cSJeremy Fitzhardinge /* balloon_append: add the given page to the balloon. */
balloon_append(struct page * page)148dde3285fSDavid Hildenbrand static void balloon_append(struct page *page)
1491775826cSJeremy Fitzhardinge {
15059b52f10SDavid Hildenbrand __SetPageOffline(page);
15159b52f10SDavid Hildenbrand
1521775826cSJeremy Fitzhardinge /* Lowmem is re-populated first, so highmem pages go at list tail. */
1531775826cSJeremy Fitzhardinge if (PageHighMem(page)) {
1541775826cSJeremy Fitzhardinge list_add_tail(&page->lru, &ballooned_pages);
1551775826cSJeremy Fitzhardinge balloon_stats.balloon_high++;
1561775826cSJeremy Fitzhardinge } else {
1571775826cSJeremy Fitzhardinge list_add(&page->lru, &ballooned_pages);
1581775826cSJeremy Fitzhardinge balloon_stats.balloon_low++;
1591775826cSJeremy Fitzhardinge }
1601cf6a6c8SDavid Vrabel wake_up(&balloon_wq);
1619be4d457SJeremy Fitzhardinge }
1623d65c948SGianluca Guida
1631775826cSJeremy Fitzhardinge /* balloon_retrieve: rescue a page from the balloon, if it is not empty. */
balloon_retrieve(bool require_lowmem)16481b286e0SDavid Vrabel static struct page *balloon_retrieve(bool require_lowmem)
1651775826cSJeremy Fitzhardinge {
1661775826cSJeremy Fitzhardinge struct page *page;
1671775826cSJeremy Fitzhardinge
1681775826cSJeremy Fitzhardinge if (list_empty(&ballooned_pages))
1691775826cSJeremy Fitzhardinge return NULL;
1701775826cSJeremy Fitzhardinge
1711775826cSJeremy Fitzhardinge page = list_entry(ballooned_pages.next, struct page, lru);
17281b286e0SDavid Vrabel if (require_lowmem && PageHighMem(page))
17381b286e0SDavid Vrabel return NULL;
1741775826cSJeremy Fitzhardinge list_del(&page->lru);
1751775826cSJeremy Fitzhardinge
1763dcc0571SJiang Liu if (PageHighMem(page))
1771775826cSJeremy Fitzhardinge balloon_stats.balloon_high--;
1783dcc0571SJiang Liu else
1791775826cSJeremy Fitzhardinge balloon_stats.balloon_low--;
1801775826cSJeremy Fitzhardinge
18104ccbdc3SDavid Hildenbrand __ClearPageOffline(page);
1821775826cSJeremy Fitzhardinge return page;
1831775826cSJeremy Fitzhardinge }
1841775826cSJeremy Fitzhardinge
balloon_next_page(struct page * page)1851775826cSJeremy Fitzhardinge static struct page *balloon_next_page(struct page *page)
1861775826cSJeremy Fitzhardinge {
1871775826cSJeremy Fitzhardinge struct list_head *next = page->lru.next;
1881775826cSJeremy Fitzhardinge if (next == &ballooned_pages)
1891775826cSJeremy Fitzhardinge return NULL;
1901775826cSJeremy Fitzhardinge return list_entry(next, struct page, lru);
1911775826cSJeremy Fitzhardinge }
1921775826cSJeremy Fitzhardinge
update_schedule(void)19340fdea02SJuergen Gross static void update_schedule(void)
1941775826cSJeremy Fitzhardinge {
19540fdea02SJuergen Gross if (balloon_state == BP_WAIT || balloon_state == BP_ECANCELED)
19640fdea02SJuergen Gross return;
197b2ac6aa8SDavid Vrabel
19840fdea02SJuergen Gross if (balloon_state == BP_DONE) {
19995d2ac4aSDaniel Kiper balloon_stats.schedule_delay = 1;
20095d2ac4aSDaniel Kiper balloon_stats.retry_count = 1;
20140fdea02SJuergen Gross return;
20295d2ac4aSDaniel Kiper }
20395d2ac4aSDaniel Kiper
20495d2ac4aSDaniel Kiper ++balloon_stats.retry_count;
20595d2ac4aSDaniel Kiper
20695d2ac4aSDaniel Kiper if (balloon_stats.max_retry_count != RETRY_UNLIMITED &&
20795d2ac4aSDaniel Kiper balloon_stats.retry_count > balloon_stats.max_retry_count) {
20895d2ac4aSDaniel Kiper balloon_stats.schedule_delay = 1;
20995d2ac4aSDaniel Kiper balloon_stats.retry_count = 1;
21040fdea02SJuergen Gross balloon_state = BP_ECANCELED;
21140fdea02SJuergen Gross return;
21295d2ac4aSDaniel Kiper }
21395d2ac4aSDaniel Kiper
21495d2ac4aSDaniel Kiper balloon_stats.schedule_delay <<= 1;
21595d2ac4aSDaniel Kiper
21695d2ac4aSDaniel Kiper if (balloon_stats.schedule_delay > balloon_stats.max_schedule_delay)
21795d2ac4aSDaniel Kiper balloon_stats.schedule_delay = balloon_stats.max_schedule_delay;
21895d2ac4aSDaniel Kiper
21940fdea02SJuergen Gross balloon_state = BP_EAGAIN;
2201775826cSJeremy Fitzhardinge }
2211775826cSJeremy Fitzhardinge
222080e2be7SDaniel Kiper #ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
release_memory_resource(struct resource * resource)223842775f1SRoss Lagerwall static void release_memory_resource(struct resource *resource)
224842775f1SRoss Lagerwall {
225842775f1SRoss Lagerwall if (!resource)
226842775f1SRoss Lagerwall return;
227842775f1SRoss Lagerwall
228842775f1SRoss Lagerwall /*
229842775f1SRoss Lagerwall * No need to reset region to identity mapped since we now
230842775f1SRoss Lagerwall * know that no I/O can be in this region
231842775f1SRoss Lagerwall */
232842775f1SRoss Lagerwall release_resource(resource);
233842775f1SRoss Lagerwall kfree(resource);
234842775f1SRoss Lagerwall }
235842775f1SRoss Lagerwall
additional_memory_resource(phys_addr_t size)23655b3da98SDavid Vrabel static struct resource *additional_memory_resource(phys_addr_t size)
23755b3da98SDavid Vrabel {
23812366410SIgor Druzhinin struct resource *res;
23912366410SIgor Druzhinin int ret;
24055b3da98SDavid Vrabel
24155b3da98SDavid Vrabel res = kzalloc(sizeof(*res), GFP_KERNEL);
24255b3da98SDavid Vrabel if (!res)
24355b3da98SDavid Vrabel return NULL;
24455b3da98SDavid Vrabel
24555b3da98SDavid Vrabel res->name = "System RAM";
246782b8664SToshi Kani res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
24755b3da98SDavid Vrabel
24855b3da98SDavid Vrabel ret = allocate_resource(&iomem_resource, res,
24955b3da98SDavid Vrabel size, 0, -1,
25055b3da98SDavid Vrabel PAGES_PER_SECTION * PAGE_SIZE, NULL, NULL);
25155b3da98SDavid Vrabel if (ret < 0) {
25255b3da98SDavid Vrabel pr_err("Cannot allocate new System RAM resource\n");
25355b3da98SDavid Vrabel kfree(res);
25455b3da98SDavid Vrabel return NULL;
25555b3da98SDavid Vrabel }
25655b3da98SDavid Vrabel
25755b3da98SDavid Vrabel return res;
25855b3da98SDavid Vrabel }
25955b3da98SDavid Vrabel
reserve_additional_memory(void)260b2ac6aa8SDavid Vrabel static enum bp_state reserve_additional_memory(void)
261080e2be7SDaniel Kiper {
262b2ac6aa8SDavid Vrabel long credit;
26355b3da98SDavid Vrabel struct resource *resource;
264080e2be7SDaniel Kiper int nid, rc;
26555b3da98SDavid Vrabel unsigned long balloon_hotplug;
266080e2be7SDaniel Kiper
2671cf6a6c8SDavid Vrabel credit = balloon_stats.target_pages + balloon_stats.target_unpopulated
2681cf6a6c8SDavid Vrabel - balloon_stats.total_pages;
269b2ac6aa8SDavid Vrabel
270b2ac6aa8SDavid Vrabel /*
271b2ac6aa8SDavid Vrabel * Already hotplugged enough pages? Wait for them to be
272b2ac6aa8SDavid Vrabel * onlined.
273b2ac6aa8SDavid Vrabel */
274b2ac6aa8SDavid Vrabel if (credit <= 0)
275b2ac6aa8SDavid Vrabel return BP_WAIT;
276b2ac6aa8SDavid Vrabel
27755b3da98SDavid Vrabel balloon_hotplug = round_up(credit, PAGES_PER_SECTION);
27855b3da98SDavid Vrabel
27955b3da98SDavid Vrabel resource = additional_memory_resource(balloon_hotplug * PAGE_SIZE);
28055b3da98SDavid Vrabel if (!resource)
28155b3da98SDavid Vrabel goto err;
28255b3da98SDavid Vrabel
28355b3da98SDavid Vrabel nid = memory_add_physaddr_to_nid(resource->start);
284080e2be7SDaniel Kiper
2853c56b3a1SJuergen Gross #ifdef CONFIG_XEN_HAVE_PVMMU
2863c56b3a1SJuergen Gross /*
28730756c62SJulien Grall * We don't support PV MMU when Linux and Xen is using
28830756c62SJulien Grall * different page granularity.
28930756c62SJulien Grall */
29030756c62SJulien Grall BUILD_BUG_ON(XEN_PAGE_SIZE != PAGE_SIZE);
29130756c62SJulien Grall
29230756c62SJulien Grall /*
2933c56b3a1SJuergen Gross * add_memory() will build page tables for the new memory so
2943c56b3a1SJuergen Gross * the p2m must contain invalid entries so the correct
2953c56b3a1SJuergen Gross * non-present PTEs will be written.
2963c56b3a1SJuergen Gross *
2973c56b3a1SJuergen Gross * If a failure occurs, the original (identity) p2m entries
2983c56b3a1SJuergen Gross * are not restored since this region is now known not to
2993c56b3a1SJuergen Gross * conflict with any devices.
3003c56b3a1SJuergen Gross */
3013c56b3a1SJuergen Gross if (!xen_feature(XENFEAT_auto_translated_physmap)) {
3023c56b3a1SJuergen Gross unsigned long pfn, i;
3033c56b3a1SJuergen Gross
30455b3da98SDavid Vrabel pfn = PFN_DOWN(resource->start);
3053c56b3a1SJuergen Gross for (i = 0; i < balloon_hotplug; i++) {
3063c56b3a1SJuergen Gross if (!set_phys_to_machine(pfn + i, INVALID_P2M_ENTRY)) {
3073c56b3a1SJuergen Gross pr_warn("set_phys_to_machine() failed, no memory added\n");
30855b3da98SDavid Vrabel goto err;
3093c56b3a1SJuergen Gross }
3103c56b3a1SJuergen Gross }
3113c56b3a1SJuergen Gross }
3123c56b3a1SJuergen Gross #endif
3133c56b3a1SJuergen Gross
314703fc13aSVitaly Kuznetsov /*
315703fc13aSVitaly Kuznetsov * add_memory_resource() will call online_pages() which in its turn
316703fc13aSVitaly Kuznetsov * will call xen_online_page() callback causing deadlock if we don't
317703fc13aSVitaly Kuznetsov * release balloon_mutex here. Unlocking here is safe because the
318703fc13aSVitaly Kuznetsov * callers drop the mutex before trying again.
319703fc13aSVitaly Kuznetsov */
320703fc13aSVitaly Kuznetsov mutex_unlock(&balloon_mutex);
3218df1d0e4SDavid Hildenbrand /* add_memory_resource() requires the device_hotplug lock */
3228df1d0e4SDavid Hildenbrand lock_device_hotplug();
32326011267SDavid Hildenbrand rc = add_memory_resource(nid, resource, MHP_MERGE_RESOURCE);
3248df1d0e4SDavid Hildenbrand unlock_device_hotplug();
325703fc13aSVitaly Kuznetsov mutex_lock(&balloon_mutex);
326703fc13aSVitaly Kuznetsov
327080e2be7SDaniel Kiper if (rc) {
3283dcf6367SDavid Vrabel pr_warn("Cannot add additional memory (%i)\n", rc);
32955b3da98SDavid Vrabel goto err;
330080e2be7SDaniel Kiper }
331080e2be7SDaniel Kiper
332de5a77d8SDavid Vrabel balloon_stats.total_pages += balloon_hotplug;
333080e2be7SDaniel Kiper
334b2ac6aa8SDavid Vrabel return BP_WAIT;
33555b3da98SDavid Vrabel err:
33655b3da98SDavid Vrabel release_memory_resource(resource);
33755b3da98SDavid Vrabel return BP_ECANCELED;
338080e2be7SDaniel Kiper }
339080e2be7SDaniel Kiper
xen_online_page(struct page * page,unsigned int order)340a9cd410aSArun KS static void xen_online_page(struct page *page, unsigned int order)
341080e2be7SDaniel Kiper {
342a9cd410aSArun KS unsigned long i, size = (1 << order);
343a9cd410aSArun KS unsigned long start_pfn = page_to_pfn(page);
344a9cd410aSArun KS struct page *p;
345080e2be7SDaniel Kiper
346a9cd410aSArun KS pr_debug("Online %lu pages starting at pfn 0x%lx\n", size, start_pfn);
347080e2be7SDaniel Kiper mutex_lock(&balloon_mutex);
348a9cd410aSArun KS for (i = 0; i < size; i++) {
349a9cd410aSArun KS p = pfn_to_page(start_pfn + i);
350dde3285fSDavid Hildenbrand balloon_append(p);
351a9cd410aSArun KS }
352080e2be7SDaniel Kiper mutex_unlock(&balloon_mutex);
353080e2be7SDaniel Kiper }
354080e2be7SDaniel Kiper
xen_memory_notifier(struct notifier_block * nb,unsigned long val,void * v)355080e2be7SDaniel Kiper static int xen_memory_notifier(struct notifier_block *nb, unsigned long val, void *v)
356080e2be7SDaniel Kiper {
357080e2be7SDaniel Kiper if (val == MEM_ONLINE)
3588480ed9cSJuergen Gross wake_up(&balloon_thread_wq);
359080e2be7SDaniel Kiper
360080e2be7SDaniel Kiper return NOTIFY_OK;
361080e2be7SDaniel Kiper }
362080e2be7SDaniel Kiper
363080e2be7SDaniel Kiper static struct notifier_block xen_memory_nb = {
364080e2be7SDaniel Kiper .notifier_call = xen_memory_notifier,
365080e2be7SDaniel Kiper .priority = 0
366080e2be7SDaniel Kiper };
367080e2be7SDaniel Kiper #else
reserve_additional_memory(void)368b2ac6aa8SDavid Vrabel static enum bp_state reserve_additional_memory(void)
369080e2be7SDaniel Kiper {
370c673ec61SJuergen Gross balloon_stats.target_pages = balloon_stats.current_pages +
371c673ec61SJuergen Gross balloon_stats.target_unpopulated;
3721cf6a6c8SDavid Vrabel return BP_ECANCELED;
373080e2be7SDaniel Kiper }
374080e2be7SDaniel Kiper #endif /* CONFIG_XEN_BALLOON_MEMORY_HOTPLUG */
375080e2be7SDaniel Kiper
current_credit(void)376de5a77d8SDavid Vrabel static long current_credit(void)
377de5a77d8SDavid Vrabel {
378de5a77d8SDavid Vrabel return balloon_stats.target_pages - balloon_stats.current_pages;
379de5a77d8SDavid Vrabel }
380de5a77d8SDavid Vrabel
balloon_is_inflated(void)381de5a77d8SDavid Vrabel static bool balloon_is_inflated(void)
382de5a77d8SDavid Vrabel {
383de5a77d8SDavid Vrabel return balloon_stats.balloon_low || balloon_stats.balloon_high;
384de5a77d8SDavid Vrabel }
385de5a77d8SDavid Vrabel
increase_reservation(unsigned long nr_pages)38695d2ac4aSDaniel Kiper static enum bp_state increase_reservation(unsigned long nr_pages)
3871775826cSJeremy Fitzhardinge {
38895d2ac4aSDaniel Kiper int rc;
38930756c62SJulien Grall unsigned long i;
3901775826cSJeremy Fitzhardinge struct page *page;
3911775826cSJeremy Fitzhardinge
3921775826cSJeremy Fitzhardinge if (nr_pages > ARRAY_SIZE(frame_list))
3931775826cSJeremy Fitzhardinge nr_pages = ARRAY_SIZE(frame_list);
3941775826cSJeremy Fitzhardinge
3959346c2a8SJie Liu page = list_first_entry_or_null(&ballooned_pages, struct page, lru);
3961775826cSJeremy Fitzhardinge for (i = 0; i < nr_pages; i++) {
39795d2ac4aSDaniel Kiper if (!page) {
39895d2ac4aSDaniel Kiper nr_pages = i;
39995d2ac4aSDaniel Kiper break;
40095d2ac4aSDaniel Kiper }
40130756c62SJulien Grall
40230756c62SJulien Grall frame_list[i] = page_to_xen_pfn(page);
4031775826cSJeremy Fitzhardinge page = balloon_next_page(page);
4041775826cSJeremy Fitzhardinge }
4051775826cSJeremy Fitzhardinge
406ae4c51a5SOleksandr Andrushchenko rc = xenmem_reservation_increase(nr_pages, frame_list);
40740095de1SKonrad Rzeszutek Wilk if (rc <= 0)
40895d2ac4aSDaniel Kiper return BP_EAGAIN;
4091775826cSJeremy Fitzhardinge
410bc2c0303SIan Campbell for (i = 0; i < rc; i++) {
411b6f30679SKonrad Rzeszutek Wilk page = balloon_retrieve(false);
4121775826cSJeremy Fitzhardinge BUG_ON(page == NULL);
4131775826cSJeremy Fitzhardinge
414ae4c51a5SOleksandr Andrushchenko xenmem_reservation_va_mapping_update(1, &page, &frame_list[i]);
4151775826cSJeremy Fitzhardinge
4161775826cSJeremy Fitzhardinge /* Relinquish the page back to the allocator. */
417709613adSRoss Lagerwall free_reserved_page(page);
4181775826cSJeremy Fitzhardinge }
4191775826cSJeremy Fitzhardinge
420bc2c0303SIan Campbell balloon_stats.current_pages += rc;
4211775826cSJeremy Fitzhardinge
42295d2ac4aSDaniel Kiper return BP_DONE;
4231775826cSJeremy Fitzhardinge }
4241775826cSJeremy Fitzhardinge
decrease_reservation(unsigned long nr_pages,gfp_t gfp)425b6f30679SKonrad Rzeszutek Wilk static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp)
4261775826cSJeremy Fitzhardinge {
42795d2ac4aSDaniel Kiper enum bp_state state = BP_DONE;
42830756c62SJulien Grall unsigned long i;
42930756c62SJulien Grall struct page *page, *tmp;
4301775826cSJeremy Fitzhardinge int ret;
43130756c62SJulien Grall LIST_HEAD(pages);
4321775826cSJeremy Fitzhardinge
4331775826cSJeremy Fitzhardinge if (nr_pages > ARRAY_SIZE(frame_list))
4341775826cSJeremy Fitzhardinge nr_pages = ARRAY_SIZE(frame_list);
4351775826cSJeremy Fitzhardinge
4361775826cSJeremy Fitzhardinge for (i = 0; i < nr_pages; i++) {
437fce92683SLisa Nguyen page = alloc_page(gfp);
438fce92683SLisa Nguyen if (page == NULL) {
4391775826cSJeremy Fitzhardinge nr_pages = i;
44095d2ac4aSDaniel Kiper state = BP_EAGAIN;
4411775826cSJeremy Fitzhardinge break;
4421775826cSJeremy Fitzhardinge }
443709613adSRoss Lagerwall adjust_managed_page_count(page, -1);
444ae4c51a5SOleksandr Andrushchenko xenmem_reservation_scrub_page(page);
44530756c62SJulien Grall list_add(&page->lru, &pages);
44609ed3d5bSWei Liu }
44709ed3d5bSWei Liu
44809ed3d5bSWei Liu /*
44909ed3d5bSWei Liu * Ensure that ballooned highmem pages don't have kmaps.
45009ed3d5bSWei Liu *
45109ed3d5bSWei Liu * Do this before changing the p2m as kmap_flush_unused()
45209ed3d5bSWei Liu * reads PTEs to obtain pages (and hence needs the original
45309ed3d5bSWei Liu * p2m entry).
45409ed3d5bSWei Liu */
45509ed3d5bSWei Liu kmap_flush_unused();
45609ed3d5bSWei Liu
45730756c62SJulien Grall /*
45830756c62SJulien Grall * Setup the frame, update direct mapping, invalidate P2M,
45930756c62SJulien Grall * and add to balloon.
46030756c62SJulien Grall */
46130756c62SJulien Grall i = 0;
46230756c62SJulien Grall list_for_each_entry_safe(page, tmp, &pages, lru) {
46330756c62SJulien Grall frame_list[i++] = xen_page_to_gfn(page);
46409ed3d5bSWei Liu
465ae4c51a5SOleksandr Andrushchenko xenmem_reservation_va_mapping_reset(1, &page);
46630756c62SJulien Grall
46730756c62SJulien Grall list_del(&page->lru);
46824f69373SDavid Vrabel
46909ed3d5bSWei Liu balloon_append(page);
4701775826cSJeremy Fitzhardinge }
4711775826cSJeremy Fitzhardinge
47224f69373SDavid Vrabel flush_tlb_all();
4732bad07ceSDavid Vrabel
474ae4c51a5SOleksandr Andrushchenko ret = xenmem_reservation_decrease(nr_pages, frame_list);
4751775826cSJeremy Fitzhardinge BUG_ON(ret != nr_pages);
4761775826cSJeremy Fitzhardinge
4771775826cSJeremy Fitzhardinge balloon_stats.current_pages -= nr_pages;
4781775826cSJeremy Fitzhardinge
47995d2ac4aSDaniel Kiper return state;
4801775826cSJeremy Fitzhardinge }
4811775826cSJeremy Fitzhardinge
4821775826cSJeremy Fitzhardinge /*
483319933a8SJuergen Gross * Stop waiting if either state is BP_DONE and ballooning action is
484319933a8SJuergen Gross * needed, or if the credit has changed while state is not BP_DONE.
4858480ed9cSJuergen Gross */
balloon_thread_cond(long credit)48640fdea02SJuergen Gross static bool balloon_thread_cond(long credit)
4878480ed9cSJuergen Gross {
48840fdea02SJuergen Gross if (balloon_state == BP_DONE)
4898480ed9cSJuergen Gross credit = 0;
4908480ed9cSJuergen Gross
4918480ed9cSJuergen Gross return current_credit() != credit || kthread_should_stop();
4928480ed9cSJuergen Gross }
4938480ed9cSJuergen Gross
4948480ed9cSJuergen Gross /*
4958480ed9cSJuergen Gross * As this is a kthread it is guaranteed to run as a single instance only.
4961775826cSJeremy Fitzhardinge * We may of course race updates of the target counts (which are protected
4971775826cSJeremy Fitzhardinge * by the balloon lock), or with changes to the Xen hard limit, but we will
4981775826cSJeremy Fitzhardinge * recover from these in time.
4991775826cSJeremy Fitzhardinge */
balloon_thread(void * unused)5008480ed9cSJuergen Gross static int balloon_thread(void *unused)
5011775826cSJeremy Fitzhardinge {
5021775826cSJeremy Fitzhardinge long credit;
5038480ed9cSJuergen Gross unsigned long timeout;
5041775826cSJeremy Fitzhardinge
5058480ed9cSJuergen Gross set_freezable();
5068480ed9cSJuergen Gross for (;;) {
50740fdea02SJuergen Gross switch (balloon_state) {
508319933a8SJuergen Gross case BP_DONE:
509319933a8SJuergen Gross case BP_ECANCELED:
5108480ed9cSJuergen Gross timeout = 3600 * HZ;
511319933a8SJuergen Gross break;
512319933a8SJuergen Gross case BP_EAGAIN:
513319933a8SJuergen Gross timeout = balloon_stats.schedule_delay * HZ;
514319933a8SJuergen Gross break;
515319933a8SJuergen Gross case BP_WAIT:
516319933a8SJuergen Gross timeout = HZ;
517319933a8SJuergen Gross break;
518319933a8SJuergen Gross }
519319933a8SJuergen Gross
5208480ed9cSJuergen Gross credit = current_credit();
5211775826cSJeremy Fitzhardinge
52296f5bd03SJuergen Gross wait_event_freezable_timeout(balloon_thread_wq,
52340fdea02SJuergen Gross balloon_thread_cond(credit), timeout);
5248480ed9cSJuergen Gross
5258480ed9cSJuergen Gross if (kthread_should_stop())
5268480ed9cSJuergen Gross return 0;
5278480ed9cSJuergen Gross
528929423faSJuergen Gross mutex_lock(&balloon_mutex);
529929423faSJuergen Gross
53083be7e52SDaniel Kiper credit = current_credit();
53195d2ac4aSDaniel Kiper
532080e2be7SDaniel Kiper if (credit > 0) {
533080e2be7SDaniel Kiper if (balloon_is_inflated())
53440fdea02SJuergen Gross balloon_state = increase_reservation(credit);
535080e2be7SDaniel Kiper else
53640fdea02SJuergen Gross balloon_state = reserve_additional_memory();
537080e2be7SDaniel Kiper }
53895d2ac4aSDaniel Kiper
539a1078e82SJuergen Gross if (credit < 0) {
540a1078e82SJuergen Gross long n_pages;
541a1078e82SJuergen Gross
542a1078e82SJuergen Gross n_pages = min(-credit, si_mem_available());
54340fdea02SJuergen Gross balloon_state = decrease_reservation(n_pages,
54440fdea02SJuergen Gross GFP_BALLOON);
54540fdea02SJuergen Gross if (balloon_state == BP_DONE && n_pages != -credit &&
546a1078e82SJuergen Gross n_pages < totalreserve_pages)
54740fdea02SJuergen Gross balloon_state = BP_EAGAIN;
548a1078e82SJuergen Gross }
54995d2ac4aSDaniel Kiper
55040fdea02SJuergen Gross update_schedule();
5511775826cSJeremy Fitzhardinge
552929423faSJuergen Gross mutex_unlock(&balloon_mutex);
553929423faSJuergen Gross
554929423faSJuergen Gross cond_resched();
5558480ed9cSJuergen Gross }
5561775826cSJeremy Fitzhardinge }
5571775826cSJeremy Fitzhardinge
5581775826cSJeremy Fitzhardinge /* Resets the Xen limit, sets new target, and kicks off processing. */
balloon_set_new_target(unsigned long target)559803eb047SDaniel De Graaf void balloon_set_new_target(unsigned long target)
5601775826cSJeremy Fitzhardinge {
5611775826cSJeremy Fitzhardinge /* No need for lock. Not read-modify-write updates. */
5621775826cSJeremy Fitzhardinge balloon_stats.target_pages = target;
5638480ed9cSJuergen Gross wake_up(&balloon_thread_wq);
5641775826cSJeremy Fitzhardinge }
565803eb047SDaniel De Graaf EXPORT_SYMBOL_GPL(balloon_set_new_target);
5661775826cSJeremy Fitzhardinge
add_ballooned_pages(unsigned int nr_pages)567121f2facSJuergen Gross static int add_ballooned_pages(unsigned int nr_pages)
5681cf6a6c8SDavid Vrabel {
5691cf6a6c8SDavid Vrabel enum bp_state st;
5701cf6a6c8SDavid Vrabel
5711cf6a6c8SDavid Vrabel if (xen_hotplug_unpopulated) {
5721cf6a6c8SDavid Vrabel st = reserve_additional_memory();
5731cf6a6c8SDavid Vrabel if (st != BP_ECANCELED) {
57488a479ffSRoger Pau Monne int rc;
57588a479ffSRoger Pau Monne
5761cf6a6c8SDavid Vrabel mutex_unlock(&balloon_mutex);
57788a479ffSRoger Pau Monne rc = wait_event_interruptible(balloon_wq,
5781cf6a6c8SDavid Vrabel !list_empty(&ballooned_pages));
5791cf6a6c8SDavid Vrabel mutex_lock(&balloon_mutex);
58088a479ffSRoger Pau Monne return rc ? -ENOMEM : 0;
5811cf6a6c8SDavid Vrabel }
5821cf6a6c8SDavid Vrabel }
5831cf6a6c8SDavid Vrabel
584a1078e82SJuergen Gross if (si_mem_available() < nr_pages)
585a1078e82SJuergen Gross return -ENOMEM;
586a1078e82SJuergen Gross
5871cf6a6c8SDavid Vrabel st = decrease_reservation(nr_pages, GFP_USER);
5881cf6a6c8SDavid Vrabel if (st != BP_DONE)
5891cf6a6c8SDavid Vrabel return -ENOMEM;
5901cf6a6c8SDavid Vrabel
5911cf6a6c8SDavid Vrabel return 0;
5921cf6a6c8SDavid Vrabel }
5931cf6a6c8SDavid Vrabel
594b6f30679SKonrad Rzeszutek Wilk /**
5959dd060afSOleksandr Tyshchenko * xen_alloc_ballooned_pages - get pages that have been ballooned out
596b6f30679SKonrad Rzeszutek Wilk * @nr_pages: Number of pages to get
597b6f30679SKonrad Rzeszutek Wilk * @pages: pages returned
598b6f30679SKonrad Rzeszutek Wilk * @return 0 on success, error otherwise
5991775826cSJeremy Fitzhardinge */
xen_alloc_ballooned_pages(unsigned int nr_pages,struct page ** pages)6009dd060afSOleksandr Tyshchenko int xen_alloc_ballooned_pages(unsigned int nr_pages, struct page **pages)
6011775826cSJeremy Fitzhardinge {
602121f2facSJuergen Gross unsigned int pgno = 0;
603b6f30679SKonrad Rzeszutek Wilk struct page *page;
6041cf6a6c8SDavid Vrabel int ret;
6051cf6a6c8SDavid Vrabel
606b6f30679SKonrad Rzeszutek Wilk mutex_lock(&balloon_mutex);
6071cf6a6c8SDavid Vrabel
6081cf6a6c8SDavid Vrabel balloon_stats.target_unpopulated += nr_pages;
6091cf6a6c8SDavid Vrabel
610b6f30679SKonrad Rzeszutek Wilk while (pgno < nr_pages) {
61181b286e0SDavid Vrabel page = balloon_retrieve(true);
61281b286e0SDavid Vrabel if (page) {
613b6f30679SKonrad Rzeszutek Wilk pages[pgno++] = page;
6144a69c909SDavid Vrabel #ifdef CONFIG_XEN_HAVE_PVMMU
61530756c62SJulien Grall /*
61630756c62SJulien Grall * We don't support PV MMU when Linux and Xen is using
61730756c62SJulien Grall * different page granularity.
61830756c62SJulien Grall */
61930756c62SJulien Grall BUILD_BUG_ON(XEN_PAGE_SIZE != PAGE_SIZE);
62030756c62SJulien Grall
621b194da25SBoris Ostrovsky if (!xen_feature(XENFEAT_auto_translated_physmap)) {
6224a69c909SDavid Vrabel ret = xen_alloc_p2m_entry(page_to_pfn(page));
6234a69c909SDavid Vrabel if (ret < 0)
6244a69c909SDavid Vrabel goto out_undo;
625b194da25SBoris Ostrovsky }
6264a69c909SDavid Vrabel #endif
627b6f30679SKonrad Rzeszutek Wilk } else {
6281cf6a6c8SDavid Vrabel ret = add_ballooned_pages(nr_pages - pgno);
6291cf6a6c8SDavid Vrabel if (ret < 0)
630b6f30679SKonrad Rzeszutek Wilk goto out_undo;
631b6f30679SKonrad Rzeszutek Wilk }
632b6f30679SKonrad Rzeszutek Wilk }
633b6f30679SKonrad Rzeszutek Wilk mutex_unlock(&balloon_mutex);
634b6f30679SKonrad Rzeszutek Wilk return 0;
635b6f30679SKonrad Rzeszutek Wilk out_undo:
636b6f30679SKonrad Rzeszutek Wilk mutex_unlock(&balloon_mutex);
6379dd060afSOleksandr Tyshchenko xen_free_ballooned_pages(pgno, pages);
6381951fa33SRoger Pau Monne /*
6399dd060afSOleksandr Tyshchenko * NB: xen_free_ballooned_pages will only subtract pgno pages, but since
6401951fa33SRoger Pau Monne * target_unpopulated is incremented with nr_pages at the start we need
6411951fa33SRoger Pau Monne * to remove the remaining ones also, or accounting will be screwed.
6421951fa33SRoger Pau Monne */
6431951fa33SRoger Pau Monne balloon_stats.target_unpopulated -= nr_pages - pgno;
6441cf6a6c8SDavid Vrabel return ret;
645b6f30679SKonrad Rzeszutek Wilk }
6469dd060afSOleksandr Tyshchenko EXPORT_SYMBOL(xen_alloc_ballooned_pages);
6471775826cSJeremy Fitzhardinge
648b6f30679SKonrad Rzeszutek Wilk /**
6499dd060afSOleksandr Tyshchenko * xen_free_ballooned_pages - return pages retrieved with get_ballooned_pages
650b6f30679SKonrad Rzeszutek Wilk * @nr_pages: Number of pages
651b6f30679SKonrad Rzeszutek Wilk * @pages: pages to return
652b6f30679SKonrad Rzeszutek Wilk */
xen_free_ballooned_pages(unsigned int nr_pages,struct page ** pages)6539dd060afSOleksandr Tyshchenko void xen_free_ballooned_pages(unsigned int nr_pages, struct page **pages)
654b6f30679SKonrad Rzeszutek Wilk {
655121f2facSJuergen Gross unsigned int i;
6561775826cSJeremy Fitzhardinge
657b6f30679SKonrad Rzeszutek Wilk mutex_lock(&balloon_mutex);
658b6f30679SKonrad Rzeszutek Wilk
659b6f30679SKonrad Rzeszutek Wilk for (i = 0; i < nr_pages; i++) {
66059b52f10SDavid Hildenbrand if (pages[i])
661b6f30679SKonrad Rzeszutek Wilk balloon_append(pages[i]);
6621775826cSJeremy Fitzhardinge }
6631775826cSJeremy Fitzhardinge
6641cf6a6c8SDavid Vrabel balloon_stats.target_unpopulated -= nr_pages;
6651cf6a6c8SDavid Vrabel
666b6f30679SKonrad Rzeszutek Wilk /* The balloon may be too large now. Shrink it if needed. */
66783be7e52SDaniel Kiper if (current_credit())
6688480ed9cSJuergen Gross wake_up(&balloon_thread_wq);
669b6f30679SKonrad Rzeszutek Wilk
670b6f30679SKonrad Rzeszutek Wilk mutex_unlock(&balloon_mutex);
671b6f30679SKonrad Rzeszutek Wilk }
6729dd060afSOleksandr Tyshchenko EXPORT_SYMBOL(xen_free_ballooned_pages);
6731775826cSJeremy Fitzhardinge
balloon_add_regions(void)674262fc47aSJuergen Gross static void __init balloon_add_regions(void)
6751775826cSJeremy Fitzhardinge {
676262fc47aSJuergen Gross unsigned long start_pfn, pages;
6774dfe22f5SDaniel Kiper unsigned long pfn, extra_pfn_end;
678262fc47aSJuergen Gross unsigned int i;
679262fc47aSJuergen Gross
680262fc47aSJuergen Gross for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) {
681262fc47aSJuergen Gross pages = xen_extra_mem[i].n_pfns;
682262fc47aSJuergen Gross if (!pages)
683262fc47aSJuergen Gross continue;
684262fc47aSJuergen Gross
685262fc47aSJuergen Gross start_pfn = xen_extra_mem[i].start_pfn;
6861775826cSJeremy Fitzhardinge
6878b5d44a5SDavid Vrabel /*
6888b5d44a5SDavid Vrabel * If the amount of usable memory has been limited (e.g., with
6898b5d44a5SDavid Vrabel * the 'mem' command line parameter), don't add pages beyond
6908b5d44a5SDavid Vrabel * this limit.
6918b5d44a5SDavid Vrabel */
6928b5d44a5SDavid Vrabel extra_pfn_end = min(max_pfn, start_pfn + pages);
6938b5d44a5SDavid Vrabel
694262fc47aSJuergen Gross for (pfn = start_pfn; pfn < extra_pfn_end; pfn++)
69559b52f10SDavid Hildenbrand balloon_append(pfn_to_page(pfn));
696de5a77d8SDavid Vrabel
697de5a77d8SDavid Vrabel balloon_stats.total_pages += extra_pfn_end - start_pfn;
6988b5d44a5SDavid Vrabel }
699262fc47aSJuergen Gross }
7008b5d44a5SDavid Vrabel
balloon_init(void)7018b5d44a5SDavid Vrabel static int __init balloon_init(void)
7028b5d44a5SDavid Vrabel {
7038480ed9cSJuergen Gross struct task_struct *task;
7048480ed9cSJuergen Gross
70553d5522cSStefano Stabellini if (!xen_domain())
7061775826cSJeremy Fitzhardinge return -ENODEV;
7071775826cSJeremy Fitzhardinge
708283c0972SJoe Perches pr_info("Initialising balloon driver\n");
7091775826cSJeremy Fitzhardinge
7104fee9ad8SVitaly Kuznetsov #ifdef CONFIG_XEN_PV
711aa24411bSDavid Vrabel balloon_stats.current_pages = xen_pv_domain()
712aa24411bSDavid Vrabel ? min(xen_start_info->nr_pages - xen_released_pages, max_pfn)
713c275a57fSBoris Ostrovsky : get_num_physpages();
7144fee9ad8SVitaly Kuznetsov #else
7154fee9ad8SVitaly Kuznetsov balloon_stats.current_pages = get_num_physpages();
7164fee9ad8SVitaly Kuznetsov #endif
7171775826cSJeremy Fitzhardinge balloon_stats.target_pages = balloon_stats.current_pages;
7181775826cSJeremy Fitzhardinge balloon_stats.balloon_low = 0;
7191775826cSJeremy Fitzhardinge balloon_stats.balloon_high = 0;
720de5a77d8SDavid Vrabel balloon_stats.total_pages = balloon_stats.current_pages;
7211775826cSJeremy Fitzhardinge
72295d2ac4aSDaniel Kiper balloon_stats.schedule_delay = 1;
72395d2ac4aSDaniel Kiper balloon_stats.max_schedule_delay = 32;
72495d2ac4aSDaniel Kiper balloon_stats.retry_count = 1;
725a1078e82SJuergen Gross balloon_stats.max_retry_count = 4;
7261775826cSJeremy Fitzhardinge
727080e2be7SDaniel Kiper #ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
728080e2be7SDaniel Kiper set_online_page_callback(&xen_online_page);
729080e2be7SDaniel Kiper register_memory_notifier(&xen_memory_nb);
730*9f17a75bSLuis Chamberlain register_sysctl_init("xen/balloon", balloon_table);
731080e2be7SDaniel Kiper #endif
732080e2be7SDaniel Kiper
733262fc47aSJuergen Gross balloon_add_regions();
7341775826cSJeremy Fitzhardinge
7358480ed9cSJuergen Gross task = kthread_run(balloon_thread, NULL, "xen-balloon");
7368480ed9cSJuergen Gross if (IS_ERR(task)) {
7378480ed9cSJuergen Gross pr_err("xen-balloon thread could not be started, ballooning will not work!\n");
7388480ed9cSJuergen Gross return PTR_ERR(task);
7398480ed9cSJuergen Gross }
7408480ed9cSJuergen Gross
74196edd61dSJuergen Gross /* Init the xen-balloon driver. */
74296edd61dSJuergen Gross xen_balloon_init();
74396edd61dSJuergen Gross
7441775826cSJeremy Fitzhardinge return 0;
7451775826cSJeremy Fitzhardinge }
7461775826cSJeremy Fitzhardinge subsys_initcall(balloon_init);
74740fdea02SJuergen Gross
balloon_wait_finish(void)74840fdea02SJuergen Gross static int __init balloon_wait_finish(void)
74940fdea02SJuergen Gross {
75040fdea02SJuergen Gross long credit, last_credit = 0;
75140fdea02SJuergen Gross unsigned long last_changed = 0;
75240fdea02SJuergen Gross
75340fdea02SJuergen Gross if (!xen_domain())
75440fdea02SJuergen Gross return -ENODEV;
75540fdea02SJuergen Gross
75640fdea02SJuergen Gross /* PV guests don't need to wait. */
75740fdea02SJuergen Gross if (xen_pv_domain() || !current_credit())
75840fdea02SJuergen Gross return 0;
75940fdea02SJuergen Gross
76040fdea02SJuergen Gross pr_notice("Waiting for initial ballooning down having finished.\n");
76140fdea02SJuergen Gross
76240fdea02SJuergen Gross while ((credit = current_credit()) < 0) {
76340fdea02SJuergen Gross if (credit != last_credit) {
76440fdea02SJuergen Gross last_changed = jiffies;
76540fdea02SJuergen Gross last_credit = credit;
76640fdea02SJuergen Gross }
76740fdea02SJuergen Gross if (balloon_state == BP_ECANCELED) {
76840fdea02SJuergen Gross pr_warn_once("Initial ballooning failed, %ld pages need to be freed.\n",
76940fdea02SJuergen Gross -credit);
770b537bf42SWang Qing if (time_is_before_eq_jiffies(last_changed + HZ * balloon_boot_timeout))
77140fdea02SJuergen Gross panic("Initial ballooning failed!\n");
77240fdea02SJuergen Gross }
77340fdea02SJuergen Gross
77440fdea02SJuergen Gross schedule_timeout_interruptible(HZ / 10);
77540fdea02SJuergen Gross }
77640fdea02SJuergen Gross
77740fdea02SJuergen Gross pr_notice("Initial ballooning down finished.\n");
77840fdea02SJuergen Gross
77940fdea02SJuergen Gross return 0;
78040fdea02SJuergen Gross }
78140fdea02SJuergen Gross late_initcall_sync(balloon_wait_finish);
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