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mm/balloon_compaction: remove balloon mapping and flag AS_BALLOON_MAP 

Now ballooned pages are detected using PageBalloon().  Fake mapping is no
longer required.  This patch links ballooned pages to balloon device using
field page->private instead of page->mapping.  Also this patch embeds
balloon_dev_info directly into struct virtio_balloon.

Signed-off-by: Konstantin Khlebnikov <k.khlebnikov@samsung.com>
Cc: Rafael Aquini <aquini@redhat.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Konstantin Khlebnikov 2014-10-09 15:29:29 -07:00 committed by Linus Torvalds
parent d6d86c0a7f
commit 9d1ba80564
4 changed files with 39 additions and 206 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

60
drivers/virtio/virtio_balloon.c
View File

@ -59,7 +59,7 @@ struct virtio_balloon
* Each page on this list adds VIRTIO_BALLOON_PAGES_PER_PAGE
* to num_pages above.
*/
struct balloon_dev_info *vb_dev_info;
struct balloon_dev_info vb_dev_info;
/* Synchronize access/update to this struct virtio_balloon elements */
struct mutex balloon_lock;
@ -127,7 +127,7 @@ static void set_page_pfns(u32 pfns[], struct page *page)
static void fill_balloon(struct virtio_balloon *vb, size_t num)
{
struct balloon_dev_info *vb_dev_info = vb->vb_dev_info;
struct balloon_dev_info *vb_dev_info = &vb->vb_dev_info;
/* We can only do one array worth at a time. */
num = min(num, ARRAY_SIZE(vb->pfns));
@ -171,7 +171,7 @@ static void release_pages_by_pfn(const u32 pfns[], unsigned int num)
static void leak_balloon(struct virtio_balloon *vb, size_t num)
{
struct page *page;
struct balloon_dev_info *vb_dev_info = vb->vb_dev_info;
struct balloon_dev_info *vb_dev_info = &vb->vb_dev_info;
/* We can only do one array worth at a time. */
num = min(num, ARRAY_SIZE(vb->pfns));
@ -353,12 +353,11 @@ static int init_vqs(struct virtio_balloon *vb)
return 0;
}
static const struct address_space_operations virtio_balloon_aops;
#ifdef CONFIG_BALLOON_COMPACTION
/*
* virtballoon_migratepage - perform the balloon page migration on behalf of
* a compation thread. (called under page lock)
* @mapping: the page->mapping which will be assigned to the new migrated page.
* @vb_dev_info: the balloon device
* @newpage: page that will replace the isolated page after migration finishes.
* @page : the isolated (old) page that is about to be migrated to newpage.
* @mode : compaction mode -- not used for balloon page migration.
@ -373,17 +372,13 @@ static const struct address_space_operations virtio_balloon_aops;
* This function preforms the balloon page migration task.
* Called through balloon_mapping->a_ops->migratepage
*/
static int virtballoon_migratepage(struct address_space *mapping,
static int virtballoon_migratepage(struct balloon_dev_info *vb_dev_info,
struct page *newpage, struct page *page, enum migrate_mode mode)
{
struct balloon_dev_info *vb_dev_info = balloon_page_device(page);
struct virtio_balloon *vb;
struct virtio_balloon *vb = container_of(vb_dev_info,
struct virtio_balloon, vb_dev_info);
unsigned long flags;
BUG_ON(!vb_dev_info);
vb = vb_dev_info->balloon_device;
/*
* In order to avoid lock contention while migrating pages concurrently
* to leak_balloon() or fill_balloon() we just give up the balloon_lock
@ -399,7 +394,7 @@ static int virtballoon_migratepage(struct address_space *mapping,
/* balloon's page migration 1st step -- inflate "newpage" */
spin_lock_irqsave(&vb_dev_info->pages_lock, flags);
balloon_page_insert(newpage, mapping, &vb_dev_info->pages);
balloon_page_insert(vb_dev_info, newpage);
vb_dev_info->isolated_pages--;
spin_unlock_irqrestore(&vb_dev_info->pages_lock, flags);
vb->num_pfns = VIRTIO_BALLOON_PAGES_PER_PAGE;
@ -418,18 +413,11 @@ static int virtballoon_migratepage(struct address_space *mapping,
return MIGRATEPAGE_SUCCESS;
}
/* define the balloon_mapping->a_ops callback to allow balloon page migration */
static const struct address_space_operations virtio_balloon_aops = {
.migratepage = virtballoon_migratepage,
};
#endif /* CONFIG_BALLOON_COMPACTION */
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;
vdev->priv = vb = kmalloc(sizeof(*vb), GFP_KERNEL);
@ -445,30 +433,14 @@ static int virtballoon_probe(struct virtio_device *vdev)
vb->vdev = vdev;
vb->need_stats_update = 0;
vb_devinfo = balloon_devinfo_alloc(vb);
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;
balloon_devinfo_init(&vb->vb_dev_info);
#ifdef CONFIG_BALLOON_COMPACTION
vb->vb_dev_info.migratepage = virtballoon_migratepage;
#endif
err = init_vqs(vb);
if (err)
goto out_free_vb_mapping;
goto out_free_vb;
vb->thread = kthread_run(balloon, vb, "vballoon");
if (IS_ERR(vb->thread)) {
@ -480,10 +452,6 @@ 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:
kfree(vb);
out:
@ -509,8 +477,6 @@ 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);
}

72
include/linux/balloon_compaction.h
View File

@ -57,21 +57,22 @@
* balloon driver as a page book-keeper for its registered balloon devices.
*/
struct balloon_dev_info {
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 */
int (*migratepage)(struct balloon_dev_info *, struct page *newpage,
struct page *page, enum migrate_mode mode);
};
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);
static inline void balloon_devinfo_free(struct balloon_dev_info *b_dev_info)
static inline void balloon_devinfo_init(struct balloon_dev_info *balloon)
{
kfree(b_dev_info);
balloon->isolated_pages = 0;
spin_lock_init(&balloon->pages_lock);
INIT_LIST_HEAD(&balloon->pages);
balloon->migratepage = NULL;
}
#ifdef CONFIG_BALLOON_COMPACTION
@ -79,14 +80,6 @@ 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);
}
/*
* __is_movable_balloon_page - helper to perform @page PageBalloon tests
@ -120,27 +113,25 @@ static inline bool isolated_balloon_page(struct page *page)
/*
* balloon_page_insert - insert a page into the balloon's page list and make
* the page->mapping assignment accordingly.
* the page->private assignment accordingly.
* @balloon : pointer to balloon device
* @page : page to be assigned as a 'balloon page'
* @mapping : allocated special 'balloon_mapping'
* @head : balloon's device page list head
*
* Caller must ensure the page is locked and the spin_lock protecting balloon
* pages list is held before inserting a page into the balloon device.
*/
static inline void balloon_page_insert(struct page *page,
struct address_space *mapping,
struct list_head *head)
static inline void balloon_page_insert(struct balloon_dev_info *balloon,
struct page *page)
{
__SetPageBalloon(page);
SetPagePrivate(page);
page->mapping = mapping;
list_add(&page->lru, head);
set_page_private(page, (unsigned long)balloon);
list_add(&page->lru, &balloon->pages);
}
/*
* balloon_page_delete - delete a page from balloon's page list and clear
* the page->mapping assignement accordingly.
* the page->private assignement accordingly.
* @page : page to be released from balloon's page list
*
* Caller must ensure the page is locked and the spin_lock protecting balloon
@ -149,7 +140,7 @@ static inline void balloon_page_insert(struct page *page,
static inline void balloon_page_delete(struct page *page)
{
__ClearPageBalloon(page);
page->mapping = NULL;
set_page_private(page, 0);
if (PagePrivate(page)) {
ClearPagePrivate(page);
list_del(&page->lru);
@ -162,11 +153,7 @@ 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 (struct balloon_dev_info *)page_private(page);
}
static inline gfp_t balloon_mapping_gfp_mask(void)
@ -174,29 +161,12 @@ 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)
static inline void balloon_page_insert(struct balloon_dev_info *balloon,
struct page *page)
{
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)
{
list_add(&page->lru, head);
list_add(&page->lru, &balloon->pages);
}
static inline void balloon_page_delete(struct page *page)
@ -240,9 +210,5 @@ 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 */

18
include/linux/pagemap.h
View File

@ -24,8 +24,7 @@ enum mapping_flags {
AS_ENOSPC = __GFP_BITS_SHIFT + 1, /* ENOSPC on async write */
AS_MM_ALL_LOCKS = __GFP_BITS_SHIFT + 2, /* under mm_take_all_locks() */
AS_UNEVICTABLE = __GFP_BITS_SHIFT + 3, /* e.g., ramdisk, SHM_LOCK */
AS_BALLOON_MAP = __GFP_BITS_SHIFT + 4, /* balloon page special map */
AS_EXITING = __GFP_BITS_SHIFT + 5, /* final truncate in progress */
AS_EXITING = __GFP_BITS_SHIFT + 4, /* final truncate in progress */
};
static inline void mapping_set_error(struct address_space *mapping, int error)
@ -55,21 +54,6 @@ static inline int mapping_unevictable(struct address_space *mapping)
return !!mapping;
}
static inline void mapping_set_balloon(struct address_space *mapping)
{
set_bit(AS_BALLOON_MAP, &mapping->flags);
}
static inline void mapping_clear_balloon(struct address_space *mapping)
{
clear_bit(AS_BALLOON_MAP, &mapping->flags);
}
static inline int mapping_balloon(struct address_space *mapping)
{
return mapping && test_bit(AS_BALLOON_MAP, &mapping->flags);
}
static inline void mapping_set_exiting(struct address_space *mapping)
{
set_bit(AS_EXITING, &mapping->flags);

95
mm/balloon_compaction.c
View File

@ -10,32 +10,6 @@
#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.
@ -61,7 +35,7 @@ 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(b_dev_info, page);
spin_unlock_irqrestore(&b_dev_info->pages_lock, flags);
unlock_page(page);
return page;
@ -127,60 +101,10 @@ 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)
{
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);
@ -192,7 +116,7 @@ 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 = balloon_page_device(page);
unsigned long flags;
spin_lock_irqsave(&b_dev_info->pages_lock, flags);
@ -202,12 +126,6 @@ static inline void __putback_balloon_page(struct page *page)
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)
{
@ -274,7 +192,7 @@ void balloon_page_putback(struct page *page)
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;
/*
@ -290,9 +208,8 @@ int balloon_page_migrate(struct page *newpage,
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;