Currently mapping for balloon_dev_info is allocated separately. That
saves some memory in case CONFIG_BALLOON_COMPACTION is disabled but
it creates a need to point from struct address_space to
balloon_dev_info. Just embed struct address_space into struct
balloon_dev_info so that we don't have to use mapping->private_data
which is going away.
Signed-off-by: Jan Kara <jack@xxxxxxx>
---
drivers/virtio/virtio_balloon.c | 22 +----------
include/linux/balloon_compaction.h | 39 ++------------------
mm/balloon_compaction.c | 75 +++++++++++---------------------------
3 files changed, 28 insertions(+), 108 deletions(-)
diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index 34bdabaecbd6..3620df32b71e 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -425,7 +425,6 @@ static const struct address_space_operations virtio_balloon_aops = {
static int virtballoon_probe(struct virtio_device *vdev)
{
struct virtio_balloon *vb;
- struct address_space *vb_mapping;
struct balloon_dev_info *vb_devinfo;
int err;
@@ -442,30 +441,16 @@ static int virtballoon_probe(struct virtio_device *vdev)
vb->vdev = vdev;
vb->need_stats_update = 0;
- vb_devinfo = balloon_devinfo_alloc(vb);
+ vb_devinfo = balloon_devinfo_alloc(vb, &virtio_balloon_aops);
if (IS_ERR(vb_devinfo)) {
err = PTR_ERR(vb_devinfo);
goto out_free_vb;
}
-
- vb_mapping = balloon_mapping_alloc(vb_devinfo,
- (balloon_compaction_check()) ?
- &virtio_balloon_aops : NULL);
- if (IS_ERR(vb_mapping)) {
- /*
- * IS_ERR(vb_mapping) && PTR_ERR(vb_mapping) == -EOPNOTSUPP
- * This means !CONFIG_BALLOON_COMPACTION, otherwise we get off.
- */
- err = PTR_ERR(vb_mapping);
- if (err != -EOPNOTSUPP)
- goto out_free_vb_devinfo;
- }
-
vb->vb_dev_info = vb_devinfo;
err = init_vqs(vb);
if (err)
- goto out_free_vb_mapping;
+ goto out_free_vb_devinfo;
vb->thread = kthread_run(balloon, vb, "vballoon");
if (IS_ERR(vb->thread)) {
@@ -477,8 +462,6 @@ static int virtballoon_probe(struct virtio_device *vdev)
out_del_vqs:
vdev->config->del_vqs(vdev);
-out_free_vb_mapping:
- balloon_mapping_free(vb_mapping);
out_free_vb_devinfo:
balloon_devinfo_free(vb_devinfo);
out_free_vb:
@@ -506,7 +489,6 @@ static void virtballoon_remove(struct virtio_device *vdev)
kthread_stop(vb->thread);
remove_common(vb);
- balloon_mapping_free(vb->vb_dev_info->mapping);
balloon_devinfo_free(vb->vb_dev_info);
kfree(vb);
}
diff --git a/include/linux/balloon_compaction.h b/include/linux/balloon_compaction.h
index 089743ade734..a11eb723561b 100644
--- a/include/linux/balloon_compaction.h
+++ b/include/linux/balloon_compaction.h
@@ -54,8 +54,8 @@
* balloon driver as a page book-keeper for its registered balloon devices.
*/
struct balloon_dev_info {
+ struct address_space mapping; /* balloon special page->mapping */
void *balloon_device; /* balloon device descriptor */
- struct address_space *mapping; /* balloon special page->mapping */
unsigned long isolated_pages; /* # of isolated pages for migration */
spinlock_t pages_lock; /* Protection to pages list */
struct list_head pages; /* Pages enqueued & handled to Host */
@@ -64,7 +64,8 @@ struct balloon_dev_info {
extern struct page *balloon_page_enqueue(struct balloon_dev_info *b_dev_info);
extern struct page *balloon_page_dequeue(struct balloon_dev_info *b_dev_info);
extern struct balloon_dev_info *balloon_devinfo_alloc(
- void *balloon_dev_descriptor);
+ void *balloon_dev_descriptor,
+ const struct address_space_operations *a_ops);
static inline void balloon_devinfo_free(struct balloon_dev_info *b_dev_info)
{
@@ -98,14 +99,6 @@ extern bool balloon_page_isolate(struct page *page);
extern void balloon_page_putback(struct page *page);
extern int balloon_page_migrate(struct page *newpage,
struct page *page, enum migrate_mode mode);
-extern struct address_space
-*balloon_mapping_alloc(struct balloon_dev_info *b_dev_info,
- const struct address_space_operations *a_ops);
-
-static inline void balloon_mapping_free(struct address_space *balloon_mapping)
-{
- kfree(balloon_mapping);
-}
/*
* page_flags_cleared - helper to perform balloon @page ->flags tests.
@@ -216,11 +209,7 @@ static inline void balloon_page_delete(struct page *page)
*/
static inline struct balloon_dev_info *balloon_page_device(struct page *page)
{
- struct address_space *mapping = page->mapping;
- if (likely(mapping))
- return mapping->private_data;
-
- return NULL;
+ return container_of(page->mapping, struct balloon_dev_info, mapping);
}
static inline gfp_t balloon_mapping_gfp_mask(void)
@@ -228,24 +217,8 @@ static inline gfp_t balloon_mapping_gfp_mask(void)
return GFP_HIGHUSER_MOVABLE;
}
-static inline bool balloon_compaction_check(void)
-{
- return true;
-}
-
#else /* !CONFIG_BALLOON_COMPACTION */
-static inline void *balloon_mapping_alloc(void *balloon_device,
- const struct address_space_operations *a_ops)
-{
- return ERR_PTR(-EOPNOTSUPP);
-}
-
-static inline void balloon_mapping_free(struct address_space *balloon_mapping)
-{
- return;
-}
-
static inline void balloon_page_insert(struct page *page,
struct address_space *mapping,
struct list_head *head)
@@ -289,9 +262,5 @@ static inline gfp_t balloon_mapping_gfp_mask(void)
return GFP_HIGHUSER;
}
-static inline bool balloon_compaction_check(void)
-{
- return false;
-}
#endif /* CONFIG_BALLOON_COMPACTION */
#endif /* _LINUX_BALLOON_COMPACTION_H */
diff --git a/mm/balloon_compaction.c b/mm/balloon_compaction.c
index 6e45a5074bf0..e5ddd28a6915 100644
--- a/mm/balloon_compaction.c
+++ b/mm/balloon_compaction.c
@@ -19,15 +19,30 @@
* 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 *balloon_devinfo_alloc(void *balloon_dev_descriptor,
+ const struct address_space_operations *a_ops)
{
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);
+ /*
+ * Give a clean 'zeroed' status to all elements of this special
+ * balloon page->mapping struct address_space instance.
+ */
+ address_space_init_once(&b_dev_info->mapping);
+
+ /*
+ * Set mapping->flags appropriately, to allow balloon pages
+ * ->mapping identification.
+ */
+ mapping_set_balloon(&b_dev_info->mapping);
+ mapping_set_gfp_mask(&b_dev_info->mapping, balloon_mapping_gfp_mask());
+
+ /* balloon's page->mapping->a_ops callback descriptor */
+ b_dev_info->mapping.a_ops = a_ops;
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);
@@ -61,7 +76,7 @@ struct page *balloon_page_enqueue(struct balloon_dev_info *b_dev_info)
*/
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(page, &b_dev_info->mapping, &b_dev_info->pages);
spin_unlock_irqrestore(&b_dev_info->pages_lock, flags);
unlock_page(page);
return page;
@@ -132,60 +147,14 @@ struct page *balloon_page_dequeue(struct balloon_dev_info *b_dev_info)
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)
+static inline struct balloon_dev_info *page_balloon_dev(struct page *page)
{
- 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;
+ return container_of(page->mapping, struct balloon_dev_info, 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 = page_balloon_device(page);
unsigned long flags;
spin_lock_irqsave(&b_dev_info->pages_lock, flags);
list_del(&page->lru);
@@ -195,7 +164,7 @@ static inline void __isolate_balloon_page(struct page *page)
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 = page_balloon_device(page);
unsigned long flags;
spin_lock_irqsave(&b_dev_info->pages_lock, flags);
list_add(&page->lru, &b_dev_info->pages);
--
1.8.1.4
--
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