*
* 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
#include <linux/bootmem.h>
#include <linux/highmem.h>
#include <linux/vmalloc.h>
-#include <asm-xen/xen_proc.h>
-#include <asm-xen/hypervisor.h>
-#include <asm-xen/ctrl_if.h>
-#include <asm-xen/balloon.h>
+#include <xen/xen_proc.h>
+#include <asm/hypervisor.h>
+#include <xen/balloon.h>
+#include <xen/interface/memory.h>
#include <asm/pgalloc.h>
#include <asm/pgtable.h>
#include <asm/uaccess.h>
#include <asm/tlb.h>
#include <linux/list.h>
+#include <xen/xenbus.h>
+
+#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;
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;
}
/*
*/
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");
git://git.onelab.eu / linux-2.6.git / blobdiff