#include <linux/export.h>
#include <linux/balloon_compaction.h>
-/*
- * balloon_devinfo_alloc - allocates a balloon device information descriptor.
- * @balloon_dev_descriptor: pointer to reference the balloon device which
- * this struct balloon_dev_info will be servicing.
- *
- * Driver must call it to properly allocate and initialize an instance of
- * struct balloon_dev_info which will be used to reference a balloon device
- * as well as to keep track of the balloon device page list.
- */
-struct balloon_dev_info *balloon_devinfo_alloc(void *balloon_dev_descriptor)
-{
- struct balloon_dev_info *b_dev_info;
- b_dev_info = kmalloc(sizeof(*b_dev_info), GFP_KERNEL);
- if (!b_dev_info)
- return ERR_PTR(-ENOMEM);
-
- b_dev_info->balloon_device = balloon_dev_descriptor;
- b_dev_info->mapping = NULL;
- b_dev_info->isolated_pages = 0;
- spin_lock_init(&b_dev_info->pages_lock);
- INIT_LIST_HEAD(&b_dev_info->pages);
-
- return b_dev_info;
-}
-EXPORT_SYMBOL_GPL(balloon_devinfo_alloc);
-
/*
* balloon_page_enqueue - allocates a new page and inserts it into the balloon
* page list.
*/
BUG_ON(!trylock_page(page));
spin_lock_irqsave(&b_dev_info->pages_lock, flags);
- balloon_page_insert(page, b_dev_info->mapping, &b_dev_info->pages);
+ balloon_page_insert(b_dev_info, page);
+ __count_vm_event(BALLOON_INFLATE);
spin_unlock_irqrestore(&b_dev_info->pages_lock, flags);
unlock_page(page);
return page;
* to be released by the balloon driver.
*/
if (trylock_page(page)) {
+ if (!PagePrivate(page)) {
+ /* raced with isolation */
+ unlock_page(page);
+ continue;
+ }
spin_lock_irqsave(&b_dev_info->pages_lock, flags);
- /*
- * Raise the page refcount here to prevent any wrong
- * attempt to isolate this page, in case of coliding
- * with balloon_page_isolate() just after we release
- * the page lock.
- *
- * balloon_page_free() will take care of dropping
- * this extra refcount later.
- */
- get_page(page);
balloon_page_delete(page);
+ __count_vm_event(BALLOON_DEFLATE);
spin_unlock_irqrestore(&b_dev_info->pages_lock, flags);
unlock_page(page);
dequeued_page = true;
EXPORT_SYMBOL_GPL(balloon_page_dequeue);
#ifdef CONFIG_BALLOON_COMPACTION
-/*
- * balloon_mapping_alloc - allocates a special ->mapping for ballooned pages.
- * @b_dev_info: holds the balloon device information descriptor.
- * @a_ops: balloon_mapping address_space_operations descriptor.
- *
- * Driver must call it to properly allocate and initialize an instance of
- * struct address_space which will be used as the special page->mapping for
- * balloon device enlisted page instances.
- */
-struct address_space *balloon_mapping_alloc(struct balloon_dev_info *b_dev_info,
- const struct address_space_operations *a_ops)
-{
- struct address_space *mapping;
-
- mapping = kmalloc(sizeof(*mapping), GFP_KERNEL);
- if (!mapping)
- return ERR_PTR(-ENOMEM);
-
- /*
- * Give a clean 'zeroed' status to all elements of this special
- * balloon page->mapping struct address_space instance.
- */
- address_space_init_once(mapping);
-
- /*
- * Set mapping->flags appropriately, to allow balloon pages
- * ->mapping identification.
- */
- mapping_set_balloon(mapping);
- mapping_set_gfp_mask(mapping, balloon_mapping_gfp_mask());
-
- /* balloon's page->mapping->a_ops callback descriptor */
- mapping->a_ops = a_ops;
-
- /*
- * Establish a pointer reference back to the balloon device descriptor
- * this particular page->mapping will be servicing.
- * This is used by compaction / migration procedures to identify and
- * access the balloon device pageset while isolating / migrating pages.
- *
- * As some balloon drivers can register multiple balloon devices
- * for a single guest, this also helps compaction / migration to
- * properly deal with multiple balloon pagesets, when required.
- */
- mapping->private_data = b_dev_info;
- b_dev_info->mapping = mapping;
-
- return mapping;
-}
-EXPORT_SYMBOL_GPL(balloon_mapping_alloc);
static inline void __isolate_balloon_page(struct page *page)
{
- struct balloon_dev_info *b_dev_info = page->mapping->private_data;
+ struct balloon_dev_info *b_dev_info = balloon_page_device(page);
unsigned long flags;
+
spin_lock_irqsave(&b_dev_info->pages_lock, flags);
+ ClearPagePrivate(page);
list_del(&page->lru);
b_dev_info->isolated_pages++;
spin_unlock_irqrestore(&b_dev_info->pages_lock, flags);
static inline void __putback_balloon_page(struct page *page)
{
- struct balloon_dev_info *b_dev_info = page->mapping->private_data;
+ struct balloon_dev_info *b_dev_info = balloon_page_device(page);
unsigned long flags;
+
spin_lock_irqsave(&b_dev_info->pages_lock, flags);
+ SetPagePrivate(page);
list_add(&page->lru, &b_dev_info->pages);
b_dev_info->isolated_pages--;
spin_unlock_irqrestore(&b_dev_info->pages_lock, flags);
}
-static inline int __migrate_balloon_page(struct address_space *mapping,
- struct page *newpage, struct page *page, enum migrate_mode mode)
-{
- return page->mapping->a_ops->migratepage(mapping, newpage, page, mode);
-}
-
/* __isolate_lru_page() counterpart for a ballooned page */
bool balloon_page_isolate(struct page *page)
{
*/
if (likely(trylock_page(page))) {
/*
- * A ballooned page, by default, has just one refcount.
+ * A ballooned page, by default, has PagePrivate set.
* Prevent concurrent compaction threads from isolating
- * an already isolated balloon page by refcount check.
+ * an already isolated balloon page by clearing it.
*/
- if (__is_movable_balloon_page(page) &&
- page_count(page) == 2) {
+ if (balloon_page_movable(page)) {
__isolate_balloon_page(page);
unlock_page(page);
return true;
int balloon_page_migrate(struct page *newpage,
struct page *page, enum migrate_mode mode)
{
- struct address_space *mapping;
+ struct balloon_dev_info *balloon = balloon_page_device(page);
int rc = -EAGAIN;
/*
return rc;
}
- mapping = page->mapping;
- if (mapping)
- rc = __migrate_balloon_page(mapping, newpage, page, mode);
+ if (balloon && balloon->migratepage)
+ rc = balloon->migratepage(balloon, newpage, page, mode);
unlock_page(newpage);
return rc;
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