X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=drivers%2Fxen%2Fballoon%2Fballoon.c;h=3226753341fd001814bfa40013c31727e46251bc;hb=cc169158e75d370ff961e5653a326a7ee1688b6b;hp=649f64c402d25a9213a2e71bc112d0c50c705fd4;hpb=207e0a826fdee4bfe853681aef2175a739c11286;p=linux-2.6.git diff --git a/drivers/xen/balloon/balloon.c b/drivers/xen/balloon/balloon.c index 649f64c40..322675334 100644 --- a/drivers/xen/balloon/balloon.c +++ b/drivers/xen/balloon/balloon.c @@ -5,9 +5,13 @@ * * Copyright (c) 2003, B Dragovic * Copyright (c) 2003-2004, M Williamson, K Fraser + * Copyright (c) 2005 Dan M. Smith, IBM Corporation * - * This file may be distributed separately from the Linux kernel, or - * incorporated into other software packages, subject to the following license: + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License version 2 + * as published by the Free Software Foundation; or, when distributed + * separately from the Linux kernel or incorporated into other + * software packages, subject to the following license: * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this source file (the "Software"), to deal in the Software without @@ -40,25 +44,43 @@ #include #include #include -#include -#include -#include -#include +#include +#include +#include +#include #include #include #include #include #include +#include + +#define PAGES2KB(_p) ((_p)<<(PAGE_SHIFT-10)) + +#ifdef CONFIG_PROC_FS static struct proc_dir_entry *balloon_pde; +#endif static DECLARE_MUTEX(balloon_mutex); -spinlock_t balloon_lock = SPIN_LOCK_UNLOCKED; + +/* + * Protects atomic reservation decrease/increase against concurrent increases. + * Also protects non-atomic updates of current_pages and driver_pages, and + * balloon lists. + */ +DEFINE_SPINLOCK(balloon_lock); /* We aim for 'current allocation' == 'target allocation'. */ static unsigned long current_pages; static unsigned long target_pages; +/* We increase/decrease in batches which fit in a page */ +static unsigned long frame_list[PAGE_SIZE / sizeof(unsigned long)]; + +/* VM /proc information for memory */ +extern unsigned long totalram_pages; + /* We may hit the hard limit in Xen. If we do then we remember it. */ static unsigned long hard_limit; @@ -77,79 +99,230 @@ static void balloon_process(void *unused); static DECLARE_WORK(balloon_worker, balloon_process, NULL); static struct timer_list balloon_timer; -#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,0) -/* Use the private and mapping fields of struct page as a list. */ -#define PAGE_TO_LIST(p) ( (struct list_head *)&p->private ) -#define LIST_TO_PAGE(l) ( list_entry( ((unsigned long *)l), \ - struct page, private ) ) -#define UNLIST_PAGE(p) do { list_del(PAGE_TO_LIST(p)); \ - p->mapping = NULL; \ - p->private = 0; } while(0) -#else -/* There's a dedicated list field in struct page we can use. */ -#define PAGE_TO_LIST(p) ( &p->list ) -#define LIST_TO_PAGE(l) ( list_entry(l, struct page, list) ) -#define UNLIST_PAGE(p) ( list_del(&p->list) ) -#define pte_offset_kernel pte_offset -#define pud_t pgd_t -#define pud_offset(d, va) d -#define pud_none(d) 0 -#define pud_bad(d) 0 -#define subsys_initcall(_fn) __initcall(_fn) -#define pfn_to_page(_pfn) (mem_map + (_pfn)) -#endif +/* When ballooning out (allocating memory to return to Xen) we don't really + want the kernel to try too hard since that can trigger the oom killer. */ +#define GFP_BALLOON \ + (GFP_HIGHUSER | __GFP_NOWARN | __GFP_NORETRY | __GFP_NOMEMALLOC) + +#define PAGE_TO_LIST(p) (&(p)->lru) +#define LIST_TO_PAGE(l) list_entry((l), struct page, lru) +#define UNLIST_PAGE(p) \ + do { \ + list_del(PAGE_TO_LIST(p)); \ + PAGE_TO_LIST(p)->next = NULL; \ + PAGE_TO_LIST(p)->prev = NULL; \ + } while(0) #define IPRINTK(fmt, args...) \ - printk(KERN_INFO "xen_mem: " fmt, ##args) + printk(KERN_INFO "xen_mem: " fmt, ##args) #define WPRINTK(fmt, args...) \ - printk(KERN_WARNING "xen_mem: " fmt, ##args) + printk(KERN_WARNING "xen_mem: " fmt, ##args) /* balloon_append: add the given page to the balloon. */ static void balloon_append(struct page *page) { - /* Low memory is re-populated first, so highmem pages go at list tail. */ - if ( PageHighMem(page) ) - { - list_add_tail(PAGE_TO_LIST(page), &ballooned_pages); - balloon_high++; - } - else - { - list_add(PAGE_TO_LIST(page), &ballooned_pages); - balloon_low++; - } + /* Lowmem is re-populated first, so highmem pages go at list tail. */ + if (PageHighMem(page)) { + list_add_tail(PAGE_TO_LIST(page), &ballooned_pages); + balloon_high++; + } else { + list_add(PAGE_TO_LIST(page), &ballooned_pages); + balloon_low++; + } } /* balloon_retrieve: rescue a page from the balloon, if it is not empty. */ static struct page *balloon_retrieve(void) { - struct page *page; + struct page *page; + + if (list_empty(&ballooned_pages)) + return NULL; + + page = LIST_TO_PAGE(ballooned_pages.next); + UNLIST_PAGE(page); - if ( list_empty(&ballooned_pages) ) - return NULL; + if (PageHighMem(page)) + balloon_high--; + else + balloon_low--; - page = LIST_TO_PAGE(ballooned_pages.next); - UNLIST_PAGE(page); + return page; +} - if ( PageHighMem(page) ) - balloon_high--; - else - balloon_low--; +static struct page *balloon_first_page(void) +{ + if (list_empty(&ballooned_pages)) + return NULL; + return LIST_TO_PAGE(ballooned_pages.next); +} - return page; +static struct page *balloon_next_page(struct page *page) +{ + struct list_head *next = PAGE_TO_LIST(page)->next; + if (next == &ballooned_pages) + return NULL; + return LIST_TO_PAGE(next); } static void balloon_alarm(unsigned long unused) { - schedule_work(&balloon_worker); + schedule_work(&balloon_worker); } static unsigned long current_target(void) { - unsigned long target = min(target_pages, hard_limit); - if ( target > (current_pages + balloon_low + balloon_high) ) - target = current_pages + balloon_low + balloon_high; - return target; + unsigned long target = min(target_pages, hard_limit); + if (target > (current_pages + balloon_low + balloon_high)) + target = current_pages + balloon_low + balloon_high; + return target; +} + +static int increase_reservation(unsigned long nr_pages) +{ + unsigned long pfn, i, flags; + struct page *page; + long rc; + struct xen_memory_reservation reservation = { + .address_bits = 0, + .extent_order = 0, + .domid = DOMID_SELF + }; + + if (nr_pages > ARRAY_SIZE(frame_list)) + nr_pages = ARRAY_SIZE(frame_list); + + balloon_lock(flags); + + page = balloon_first_page(); + for (i = 0; i < nr_pages; i++) { + BUG_ON(page == NULL); + frame_list[i] = page_to_pfn(page);; + page = balloon_next_page(page); + } + + set_xen_guest_handle(reservation.extent_start, frame_list); + reservation.nr_extents = nr_pages; + rc = HYPERVISOR_memory_op( + XENMEM_populate_physmap, &reservation); + if (rc < nr_pages) { + if (rc > 0) { + int ret; + + /* We hit the Xen hard limit: reprobe. */ + reservation.nr_extents = rc; + ret = HYPERVISOR_memory_op(XENMEM_decrease_reservation, + &reservation); + BUG_ON(ret != rc); + } + if (rc >= 0) + hard_limit = current_pages + rc - driver_pages; + goto out; + } + + for (i = 0; i < nr_pages; i++) { + page = balloon_retrieve(); + BUG_ON(page == NULL); + + pfn = page_to_pfn(page); + BUG_ON(!xen_feature(XENFEAT_auto_translated_physmap) && + phys_to_machine_mapping_valid(pfn)); + + /* Update P->M and M->P tables. */ + set_phys_to_machine(pfn, frame_list[i]); + xen_machphys_update(frame_list[i], pfn); + + /* Link back into the page tables if not highmem. */ + if (pfn < max_low_pfn) { + int ret; + ret = HYPERVISOR_update_va_mapping( + (unsigned long)__va(pfn << PAGE_SHIFT), + pfn_pte_ma(frame_list[i], PAGE_KERNEL), + 0); + BUG_ON(ret); + } + + /* Relinquish the page back to the allocator. */ + ClearPageReserved(page); + init_page_count(page); + __free_page(page); + } + + current_pages += nr_pages; + totalram_pages = current_pages; + + out: + balloon_unlock(flags); + + return 0; +} + +static int decrease_reservation(unsigned long nr_pages) +{ + unsigned long pfn, i, flags; + struct page *page; + void *v; + int need_sleep = 0; + int ret; + struct xen_memory_reservation reservation = { + .address_bits = 0, + .extent_order = 0, + .domid = DOMID_SELF + }; + + if (nr_pages > ARRAY_SIZE(frame_list)) + nr_pages = ARRAY_SIZE(frame_list); + + for (i = 0; i < nr_pages; i++) { + if ((page = alloc_page(GFP_BALLOON)) == NULL) { + nr_pages = i; + need_sleep = 1; + break; + } + + pfn = page_to_pfn(page); + frame_list[i] = pfn_to_mfn(pfn); + + if (!PageHighMem(page)) { + v = phys_to_virt(pfn << PAGE_SHIFT); + scrub_pages(v, 1); + ret = HYPERVISOR_update_va_mapping( + (unsigned long)v, __pte_ma(0), 0); + BUG_ON(ret); + } +#ifdef CONFIG_XEN_SCRUB_PAGES + else { + v = kmap(page); + scrub_pages(v, 1); + kunmap(page); + } +#endif + } + + /* Ensure that ballooned highmem pages don't have kmaps. */ + kmap_flush_unused(); + flush_tlb_all(); + + balloon_lock(flags); + + /* No more mappings: invalidate P2M and add to balloon. */ + for (i = 0; i < nr_pages; i++) { + pfn = mfn_to_pfn(frame_list[i]); + set_phys_to_machine(pfn, INVALID_P2M_ENTRY); + balloon_append(pfn_to_page(pfn)); + } + + set_xen_guest_handle(reservation.extent_start, frame_list); + reservation.nr_extents = nr_pages; + ret = HYPERVISOR_memory_op(XENMEM_decrease_reservation, &reservation); + BUG_ON(ret != nr_pages); + + current_pages -= nr_pages; + totalram_pages = current_pages; + + balloon_unlock(flags); + + return need_sleep; } /* @@ -160,279 +333,285 @@ static unsigned long current_target(void) */ static void balloon_process(void *unused) { - unsigned long *mfn_list, pfn, i, flags; - struct page *page; - long credit, debt, rc; - void *v; - - down(&balloon_mutex); - - retry: - mfn_list = NULL; - - if ( (credit = current_target() - current_pages) > 0 ) - { - mfn_list = (unsigned long *)vmalloc(credit * sizeof(*mfn_list)); - if ( mfn_list == NULL ) - goto out; - - balloon_lock(flags); - rc = HYPERVISOR_dom_mem_op( - MEMOP_increase_reservation, mfn_list, credit, 0); - balloon_unlock(flags); - if ( rc < credit ) - { - /* We hit the Xen hard limit: reprobe. */ - if ( HYPERVISOR_dom_mem_op( - MEMOP_decrease_reservation, mfn_list, rc, 0) != rc ) - BUG(); - hard_limit = current_pages + rc - driver_pages; - vfree(mfn_list); - goto retry; - } - - for ( i = 0; i < credit; i++ ) - { - if ( (page = balloon_retrieve()) == NULL ) - BUG(); - - pfn = page - mem_map; - if ( phys_to_machine_mapping[pfn] != INVALID_P2M_ENTRY ) - BUG(); - - /* Update P->M and M->P tables. */ - phys_to_machine_mapping[pfn] = mfn_list[i]; - xen_machphys_update(mfn_list[i], pfn); - - /* Link back into the page tables if it's not a highmem page. */ - if ( pfn < max_low_pfn ) - { - HYPERVISOR_update_va_mapping( - (unsigned long)__va(pfn << PAGE_SHIFT), - __pte_ma((mfn_list[i] << PAGE_SHIFT) | - pgprot_val(PAGE_KERNEL)), - 0); - } - - /* Finally, relinquish the memory back to the system allocator. */ - ClearPageReserved(page); - set_page_count(page, 1); - __free_page(page); - } - - current_pages += credit; - } - else if ( credit < 0 ) - { - debt = -credit; - - mfn_list = (unsigned long *)vmalloc(debt * sizeof(*mfn_list)); - if ( mfn_list == NULL ) - goto out; - - for ( i = 0; i < debt; i++ ) - { - if ( (page = alloc_page(GFP_HIGHUSER)) == NULL ) - { - debt = i; - break; - } - - pfn = page - mem_map; - mfn_list[i] = phys_to_machine_mapping[pfn]; - - if ( !PageHighMem(page) ) - { - v = phys_to_virt(pfn << PAGE_SHIFT); - scrub_pages(v, 1); - HYPERVISOR_update_va_mapping( - (unsigned long)v, __pte_ma(0), 0); - } -#ifdef CONFIG_XEN_SCRUB_PAGES - else - { - v = kmap(page); - scrub_pages(v, 1); - kunmap(page); - } -#endif - } + int need_sleep = 0; + long credit; - /* Ensure that ballooned highmem pages don't have cached mappings. */ - kmap_flush_unused(); - flush_tlb_all(); + down(&balloon_mutex); - /* No more mappings: invalidate pages in P2M and add to balloon. */ - for ( i = 0; i < debt; i++ ) - { - pfn = mfn_to_pfn(mfn_list[i]); - phys_to_machine_mapping[pfn] = INVALID_P2M_ENTRY; - balloon_append(pfn_to_page(pfn)); - } + do { + credit = current_target() - current_pages; + if (credit > 0) + need_sleep = (increase_reservation(credit) != 0); + if (credit < 0) + need_sleep = (decrease_reservation(-credit) != 0); - if ( HYPERVISOR_dom_mem_op( - MEMOP_decrease_reservation, mfn_list, debt, 0) != debt ) - BUG(); - - current_pages -= debt; - } - - out: - if ( mfn_list != NULL ) - vfree(mfn_list); +#ifndef CONFIG_PREEMPT + if (need_resched()) + schedule(); +#endif + } while ((credit != 0) && !need_sleep); - /* Schedule more work if there is some still to be done. */ - if ( current_target() != current_pages ) - mod_timer(&balloon_timer, jiffies + HZ); + /* Schedule more work if there is some still to be done. */ + if (current_target() != current_pages) + mod_timer(&balloon_timer, jiffies + HZ); - up(&balloon_mutex); + up(&balloon_mutex); } /* Resets the Xen limit, sets new target, and kicks off processing. */ static void set_new_target(unsigned long target) { - /* No need for lock. Not read-modify-write updates. */ - hard_limit = ~0UL; - target_pages = target; - schedule_work(&balloon_worker); + /* No need for lock. Not read-modify-write updates. */ + hard_limit = ~0UL; + target_pages = target; + schedule_work(&balloon_worker); } -static void balloon_ctrlif_rx(ctrl_msg_t *msg, unsigned long id) +static struct xenbus_watch target_watch = { - switch ( msg->subtype ) - { - case CMSG_MEM_REQUEST_SET: - { - mem_request_t *req = (mem_request_t *)&msg->msg[0]; - set_new_target(req->target); - req->status = 0; - } - break; - - default: - msg->length = 0; - break; - } - - ctrl_if_send_response(msg); + .node = "memory/target" +}; + +/* React to a change in the target key */ +static void watch_target(struct xenbus_watch *watch, + const char **vec, unsigned int len) +{ + unsigned long long new_target; + int err; + + err = xenbus_scanf(XBT_NIL, "memory", "target", "%llu", &new_target); + if (err != 1) { + /* This is ok (for domain0 at least) - so just return */ + return; + } + + /* The given memory/target value is in KiB, so it needs converting to + * pages. PAGE_SHIFT converts bytes to pages, hence PAGE_SHIFT - 10. + */ + set_new_target(new_target >> (PAGE_SHIFT - 10)); +} + +static int balloon_init_watcher(struct notifier_block *notifier, + unsigned long event, + void *data) +{ + int err; + + err = register_xenbus_watch(&target_watch); + if (err) + printk(KERN_ERR "Failed to set balloon watcher\n"); + + return NOTIFY_DONE; } +#ifdef CONFIG_PROC_FS static int balloon_write(struct file *file, const char __user *buffer, - unsigned long count, void *data) + unsigned long count, void *data) { - char memstring[64], *endchar; - unsigned long long target_bytes; + char memstring[64], *endchar; + unsigned long long target_bytes; - if ( !capable(CAP_SYS_ADMIN) ) - return -EPERM; + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; - if ( count <= 1 ) - return -EBADMSG; /* runt */ - if ( count > sizeof(memstring) ) - return -EFBIG; /* too long */ + if (count <= 1) + return -EBADMSG; /* runt */ + if (count > sizeof(memstring)) + return -EFBIG; /* too long */ - if ( copy_from_user(memstring, buffer, count) ) - return -EFAULT; - memstring[sizeof(memstring)-1] = '\0'; + if (copy_from_user(memstring, buffer, count)) + return -EFAULT; + memstring[sizeof(memstring)-1] = '\0'; - target_bytes = memparse(memstring, &endchar); - set_new_target(target_bytes >> PAGE_SHIFT); + target_bytes = memparse(memstring, &endchar); + set_new_target(target_bytes >> PAGE_SHIFT); - return count; + return count; } static int balloon_read(char *page, char **start, off_t off, - int count, int *eof, void *data) + int count, int *eof, void *data) { - int len; - -#define K(_p) ((_p)<<(PAGE_SHIFT-10)) - len = sprintf( - page, - "Current allocation: %8lu kB\n" - "Requested target: %8lu kB\n" - "Low-mem balloon: %8lu kB\n" - "High-mem balloon: %8lu kB\n" - "Xen hard limit: ", - K(current_pages), K(target_pages), K(balloon_low), K(balloon_high)); - - if ( hard_limit != ~0UL ) - len += sprintf( - page + len, - "%8lu kB (inc. %8lu kB driver headroom)\n", - K(hard_limit), K(driver_pages)); - else - len += sprintf( - page + len, - " ??? kB\n"); - - *eof = 1; - return len; + int len; + + len = sprintf( + page, + "Current allocation: %8lu kB\n" + "Requested target: %8lu kB\n" + "Low-mem balloon: %8lu kB\n" + "High-mem balloon: %8lu kB\n" + "Xen hard limit: ", + PAGES2KB(current_pages), PAGES2KB(target_pages), + PAGES2KB(balloon_low), PAGES2KB(balloon_high)); + + if (hard_limit != ~0UL) { + len += sprintf( + page + len, + "%8lu kB (inc. %8lu kB driver headroom)\n", + PAGES2KB(hard_limit), PAGES2KB(driver_pages)); + } else { + len += sprintf( + page + len, + " ??? kB\n"); + } + + *eof = 1; + return len; } +#endif + +static struct notifier_block xenstore_notifier; static int __init balloon_init(void) { - unsigned long pfn; - struct page *page; + unsigned long pfn; + struct page *page; + + if (!is_running_on_xen()) + return -ENODEV; + + IPRINTK("Initialising balloon driver.\n"); + + current_pages = min(xen_start_info->nr_pages, max_pfn); + totalram_pages = current_pages; + target_pages = current_pages; + balloon_low = 0; + balloon_high = 0; + driver_pages = 0UL; + hard_limit = ~0UL; - IPRINTK("Initialising balloon driver.\n"); + init_timer(&balloon_timer); + balloon_timer.data = 0; + balloon_timer.function = balloon_alarm; + +#ifdef CONFIG_PROC_FS + if ((balloon_pde = create_xen_proc_entry("balloon", 0644)) == NULL) { + WPRINTK("Unable to create /proc/xen/balloon.\n"); + return -1; + } + + balloon_pde->read_proc = balloon_read; + balloon_pde->write_proc = balloon_write; +#endif + + /* Initialise the balloon with excess memory space. */ + for (pfn = xen_start_info->nr_pages; pfn < max_pfn; pfn++) { + page = pfn_to_page(pfn); + if (!PageReserved(page)) + balloon_append(page); + } - current_pages = min(xen_start_info.nr_pages, max_pfn); - target_pages = current_pages; - balloon_low = 0; - balloon_high = 0; - driver_pages = 0UL; - hard_limit = ~0UL; + target_watch.callback = watch_target; + xenstore_notifier.notifier_call = balloon_init_watcher; - init_timer(&balloon_timer); - balloon_timer.data = 0; - balloon_timer.function = balloon_alarm; + register_xenstore_notifier(&xenstore_notifier); - if ( (balloon_pde = create_xen_proc_entry("balloon", 0644)) == NULL ) - { - WPRINTK("Unable to create /proc/xen/balloon.\n"); - return -1; - } - - balloon_pde->read_proc = balloon_read; - balloon_pde->write_proc = balloon_write; - - (void)ctrl_if_register_receiver(CMSG_MEM_REQUEST, balloon_ctrlif_rx, 0); - - /* Initialise the balloon with excess memory space. */ - for ( pfn = xen_start_info.nr_pages; pfn < max_pfn; pfn++ ) - { - page = &mem_map[pfn]; - if ( !PageReserved(page) ) - balloon_append(page); - } - - return 0; + return 0; } subsys_initcall(balloon_init); void balloon_update_driver_allowance(long delta) { - unsigned long flags; - balloon_lock(flags); - driver_pages += delta; /* non-atomic update */ - balloon_unlock(flags); + unsigned long flags; + + balloon_lock(flags); + driver_pages += delta; + balloon_unlock(flags); } -void balloon_put_pages(unsigned long *mfn_list, unsigned long nr_mfns) +static int dealloc_pte_fn( + pte_t *pte, struct page *pmd_page, unsigned long addr, void *data) { - unsigned long flags; + unsigned long mfn = pte_mfn(*pte); + int ret; + struct xen_memory_reservation reservation = { + .nr_extents = 1, + .extent_order = 0, + .domid = DOMID_SELF + }; + set_xen_guest_handle(reservation.extent_start, &mfn); + set_pte_at(&init_mm, addr, pte, __pte_ma(0)); + set_phys_to_machine(__pa(addr) >> PAGE_SHIFT, INVALID_P2M_ENTRY); + ret = HYPERVISOR_memory_op(XENMEM_decrease_reservation, &reservation); + BUG_ON(ret != 1); + return 0; +} - balloon_lock(flags); - if ( HYPERVISOR_dom_mem_op(MEMOP_decrease_reservation, - mfn_list, nr_mfns, 0) != nr_mfns ) - BUG(); - current_pages -= nr_mfns; /* non-atomic update */ - balloon_unlock(flags); +struct page *balloon_alloc_empty_page_range(unsigned long nr_pages) +{ + unsigned long vstart, flags; + unsigned int order = get_order(nr_pages * PAGE_SIZE); + int ret; + unsigned long i; + struct page *page; + + vstart = __get_free_pages(GFP_KERNEL, order); + if (vstart == 0) + return NULL; + + scrub_pages(vstart, 1 << order); + + balloon_lock(flags); + if (xen_feature(XENFEAT_auto_translated_physmap)) { + unsigned long gmfn = __pa(vstart) >> PAGE_SHIFT; + struct xen_memory_reservation reservation = { + .nr_extents = 1, + .extent_order = order, + .domid = DOMID_SELF + }; + set_xen_guest_handle(reservation.extent_start, &gmfn); + ret = HYPERVISOR_memory_op(XENMEM_decrease_reservation, + &reservation); + if (ret == -ENOSYS) + goto err; + BUG_ON(ret != 1); + } else { + ret = apply_to_page_range(&init_mm, vstart, PAGE_SIZE << order, + dealloc_pte_fn, NULL); + if (ret == -ENOSYS) + goto err; + BUG_ON(ret); + } + current_pages -= 1UL << order; + totalram_pages = current_pages; + balloon_unlock(flags); + + schedule_work(&balloon_worker); + + flush_tlb_all(); + + page = virt_to_page(vstart); + + for (i = 0; i < (1UL << order); i++) + init_page_count(page + i); + + return page; + + err: + free_pages(vstart, order); + balloon_unlock(flags); + return NULL; +} - schedule_work(&balloon_worker); +void balloon_dealloc_empty_page_range( + struct page *page, unsigned long nr_pages) +{ + unsigned long i, flags; + unsigned int order = get_order(nr_pages * PAGE_SIZE); + + balloon_lock(flags); + for (i = 0; i < (1UL << order); i++) { + BUG_ON(page_count(page + i) != 1); + balloon_append(page + i); + } + balloon_unlock(flags); + + schedule_work(&balloon_worker); } -EXPORT_SYMBOL(balloon_update_driver_allowance); -EXPORT_SYMBOL(balloon_put_pages); +EXPORT_SYMBOL_GPL(balloon_update_driver_allowance); +EXPORT_SYMBOL_GPL(balloon_alloc_empty_page_range); +EXPORT_SYMBOL_GPL(balloon_dealloc_empty_page_range); + +MODULE_LICENSE("Dual BSD/GPL");