* struct page(s) to form a zspage.
*
* Usage of struct page fields:
- * page->private: points to the first component (0-order) page
- * page->index (union with page->freelist): offset of the first object
- * starting in this page. For the first page, this is
- * always 0, so we use this field (aka freelist) to point
- * to the first free object in zspage.
- * page->lru: links together all component pages (except the first page)
- * of a zspage
- *
- * For _first_ page only:
- *
- * page->private: refers to the component page after the first page
- * If the page is first_page for huge object, it stores handle.
- * Look at size_class->huge.
- * page->freelist: points to the first free object in zspage.
- * Free objects are linked together using in-place
- * metadata.
- * page->lru: links together first pages of various zspages.
- * Basically forming list of zspages in a fullness group.
- * page->mapping: class index and fullness group of the zspage
- * page->inuse: the number of objects that are used in this zspage
+ * page->private: points to zspage
+ * page->freelist(index): links together all component pages of a zspage
+ * For the huge page, this is always 0, so we use this field
+ * to store handle.
+ * page->units: first object offset in a subpage of zspage
*
* Usage of struct page flags:
* PG_private: identifies the first component page
* PG_private2: identifies the last component page
+ * PG_owner_priv_1: indentifies the huge component page
*
*/
#include <linux/debugfs.h>
#include <linux/zsmalloc.h>
#include <linux/zpool.h>
+#include <linux/mount.h>
+#include <linux/migrate.h>
+#include <linux/pagemap.h>
+
+#define ZSPAGE_MAGIC 0x58
/*
* This must be power of 2 and greater than of equal to sizeof(link_free).
* Object location (<PFN>, <obj_idx>) is encoded as
* as single (unsigned long) handle value.
*
- * Note that object index <obj_idx> is relative to system
- * page <PFN> it is stored in, so for each sub-page belonging
- * to a zspage, obj_idx starts with 0.
+ * Note that object index <obj_idx> starts from 0.
*
* This is made more complicated by various memory models and PAE.
*/
* ZS_MIN_ALLOC_SIZE and ZS_SIZE_CLASS_DELTA must be multiple of ZS_ALIGN
* (reason above)
*/
-#define ZS_SIZE_CLASS_DELTA (PAGE_SIZE >> 8)
+#define ZS_SIZE_CLASS_DELTA (PAGE_SIZE >> CLASS_BITS)
-/*
- * We do not maintain any list for completely empty or full pages
- */
enum fullness_group {
- ZS_ALMOST_FULL,
- ZS_ALMOST_EMPTY,
- _ZS_NR_FULLNESS_GROUPS,
-
ZS_EMPTY,
- ZS_FULL
+ ZS_ALMOST_EMPTY,
+ ZS_ALMOST_FULL,
+ ZS_FULL,
+ NR_ZS_FULLNESS,
};
enum zs_stat_type {
+ CLASS_EMPTY,
+ CLASS_ALMOST_EMPTY,
+ CLASS_ALMOST_FULL,
+ CLASS_FULL,
OBJ_ALLOCATED,
OBJ_USED,
- CLASS_ALMOST_FULL,
- CLASS_ALMOST_EMPTY,
+ NR_ZS_STAT_TYPE,
};
-#ifdef CONFIG_ZSMALLOC_STAT
-#define NR_ZS_STAT_TYPE (CLASS_ALMOST_EMPTY + 1)
-#else
-#define NR_ZS_STAT_TYPE (OBJ_USED + 1)
-#endif
-
struct zs_size_stat {
unsigned long objs[NR_ZS_STAT_TYPE];
};
static struct dentry *zs_stat_root;
#endif
+#ifdef CONFIG_COMPACTION
+static struct vfsmount *zsmalloc_mnt;
+#endif
+
/*
* number of size_classes
*/
struct size_class {
spinlock_t lock;
- struct page *fullness_list[_ZS_NR_FULLNESS_GROUPS];
+ struct list_head fullness_list[NR_ZS_FULLNESS];
/*
* Size of objects stored in this class. Must be multiple
* of ZS_ALIGN.
*/
int size;
int objs_per_zspage;
- unsigned int index;
-
- struct zs_size_stat stats;
-
/* Number of PAGE_SIZE sized pages to combine to form a 'zspage' */
int pages_per_zspage;
- /* huge object: pages_per_zspage == 1 && maxobj_per_zspage == 1 */
- bool huge;
+
+ unsigned int index;
+ struct zs_size_stat stats;
};
+/* huge object: pages_per_zspage == 1 && maxobj_per_zspage == 1 */
+static void SetPageHugeObject(struct page *page)
+{
+ SetPageOwnerPriv1(page);
+}
+
+static void ClearPageHugeObject(struct page *page)
+{
+ ClearPageOwnerPriv1(page);
+}
+
+static int PageHugeObject(struct page *page)
+{
+ return PageOwnerPriv1(page);
+}
+
/*
* Placed within free objects to form a singly linked list.
- * For every zspage, first_page->freelist gives head of this list.
+ * For every zspage, zspage->freeobj gives head of this list.
*
* This must be power of 2 and less than or equal to ZS_ALIGN
*/
struct link_free {
union {
/*
- * Position of next free chunk (encodes <PFN, obj_idx>)
+ * Free object index;
* It's valid for non-allocated object
*/
- void *next;
+ unsigned long next;
/*
* Handle of allocated object.
*/
struct size_class **size_class;
struct kmem_cache *handle_cachep;
+ struct kmem_cache *zspage_cachep;
atomic_long_t pages_allocated;
#ifdef CONFIG_ZSMALLOC_STAT
struct dentry *stat_dentry;
#endif
+#ifdef CONFIG_COMPACTION
+ struct inode *inode;
+ struct work_struct free_work;
+#endif
};
/*
* A zspage's class index and fullness group
* are encoded in its (first)page->mapping
*/
-#define CLASS_IDX_BITS 28
-#define FULLNESS_BITS 4
-#define CLASS_IDX_MASK ((1 << CLASS_IDX_BITS) - 1)
-#define FULLNESS_MASK ((1 << FULLNESS_BITS) - 1)
+#define FULLNESS_BITS 2
+#define CLASS_BITS 8
+#define ISOLATED_BITS 3
+#define MAGIC_VAL_BITS 8
+
+struct zspage {
+ struct {
+ unsigned int fullness:FULLNESS_BITS;
+ unsigned int class:CLASS_BITS;
+ unsigned int isolated:ISOLATED_BITS;
+ unsigned int magic:MAGIC_VAL_BITS;
+ };
+ unsigned int inuse;
+ unsigned int freeobj;
+ struct page *first_page;
+ struct list_head list; /* fullness list */
+#ifdef CONFIG_COMPACTION
+ rwlock_t lock;
+#endif
+};
struct mapping_area {
#ifdef CONFIG_PGTABLE_MAPPING
enum zs_mapmode vm_mm; /* mapping mode */
};
-static int create_handle_cache(struct zs_pool *pool)
+#ifdef CONFIG_COMPACTION
+static int zs_register_migration(struct zs_pool *pool);
+static void zs_unregister_migration(struct zs_pool *pool);
+static void migrate_lock_init(struct zspage *zspage);
+static void migrate_read_lock(struct zspage *zspage);
+static void migrate_read_unlock(struct zspage *zspage);
+static void kick_deferred_free(struct zs_pool *pool);
+static void init_deferred_free(struct zs_pool *pool);
+static void SetZsPageMovable(struct zs_pool *pool, struct zspage *zspage);
+#else
+static int zsmalloc_mount(void) { return 0; }
+static void zsmalloc_unmount(void) {}
+static int zs_register_migration(struct zs_pool *pool) { return 0; }
+static void zs_unregister_migration(struct zs_pool *pool) {}
+static void migrate_lock_init(struct zspage *zspage) {}
+static void migrate_read_lock(struct zspage *zspage) {}
+static void migrate_read_unlock(struct zspage *zspage) {}
+static void kick_deferred_free(struct zs_pool *pool) {}
+static void init_deferred_free(struct zs_pool *pool) {}
+static void SetZsPageMovable(struct zs_pool *pool, struct zspage *zspage) {}
+#endif
+
+static int create_cache(struct zs_pool *pool)
{
pool->handle_cachep = kmem_cache_create("zs_handle", ZS_HANDLE_SIZE,
0, 0, NULL);
- return pool->handle_cachep ? 0 : 1;
+ if (!pool->handle_cachep)
+ return 1;
+
+ pool->zspage_cachep = kmem_cache_create("zspage", sizeof(struct zspage),
+ 0, 0, NULL);
+ if (!pool->zspage_cachep) {
+ kmem_cache_destroy(pool->handle_cachep);
+ pool->handle_cachep = NULL;
+ return 1;
+ }
+
+ return 0;
}
-static void destroy_handle_cache(struct zs_pool *pool)
+static void destroy_cache(struct zs_pool *pool)
{
kmem_cache_destroy(pool->handle_cachep);
+ kmem_cache_destroy(pool->zspage_cachep);
}
-static unsigned long alloc_handle(struct zs_pool *pool, gfp_t gfp)
+static unsigned long cache_alloc_handle(struct zs_pool *pool, gfp_t gfp)
{
return (unsigned long)kmem_cache_alloc(pool->handle_cachep,
- gfp & ~__GFP_HIGHMEM);
+ gfp & ~(__GFP_HIGHMEM|__GFP_MOVABLE));
}
-static void free_handle(struct zs_pool *pool, unsigned long handle)
+static void cache_free_handle(struct zs_pool *pool, unsigned long handle)
{
kmem_cache_free(pool->handle_cachep, (void *)handle);
}
+static struct zspage *cache_alloc_zspage(struct zs_pool *pool, gfp_t flags)
+{
+ return kmem_cache_alloc(pool->zspage_cachep,
+ flags & ~(__GFP_HIGHMEM|__GFP_MOVABLE));
+};
+
+static void cache_free_zspage(struct zs_pool *pool, struct zspage *zspage)
+{
+ kmem_cache_free(pool->zspage_cachep, zspage);
+}
+
static void record_obj(unsigned long handle, unsigned long obj)
{
/*
MODULE_ALIAS("zpool-zsmalloc");
#endif /* CONFIG_ZPOOL */
-static unsigned int get_maxobj_per_zspage(int size, int pages_per_zspage)
-{
- return pages_per_zspage * PAGE_SIZE / size;
-}
-
/* per-cpu VM mapping areas for zspage accesses that cross page boundaries */
static DEFINE_PER_CPU(struct mapping_area, zs_map_area);
+static bool is_zspage_isolated(struct zspage *zspage)
+{
+ return zspage->isolated;
+}
+
static int is_first_page(struct page *page)
{
return PagePrivate(page);
}
-static int is_last_page(struct page *page)
+/* Protected by class->lock */
+static inline int get_zspage_inuse(struct zspage *zspage)
+{
+ return zspage->inuse;
+}
+
+static inline void set_zspage_inuse(struct zspage *zspage, int val)
+{
+ zspage->inuse = val;
+}
+
+static inline void mod_zspage_inuse(struct zspage *zspage, int val)
+{
+ zspage->inuse += val;
+}
+
+static inline struct page *get_first_page(struct zspage *zspage)
+{
+ struct page *first_page = zspage->first_page;
+
+ VM_BUG_ON_PAGE(!is_first_page(first_page), first_page);
+ return first_page;
+}
+
+static inline int get_first_obj_offset(struct page *page)
+{
+ return page->units;
+}
+
+static inline void set_first_obj_offset(struct page *page, int offset)
+{
+ page->units = offset;
+}
+
+static inline unsigned int get_freeobj(struct zspage *zspage)
+{
+ return zspage->freeobj;
+}
+
+static inline void set_freeobj(struct zspage *zspage, unsigned int obj)
{
- return PagePrivate2(page);
+ zspage->freeobj = obj;
}
-static void get_zspage_mapping(struct page *first_page,
+static void get_zspage_mapping(struct zspage *zspage,
unsigned int *class_idx,
enum fullness_group *fullness)
{
- unsigned long m;
- VM_BUG_ON_PAGE(!is_first_page(first_page), first_page);
+ BUG_ON(zspage->magic != ZSPAGE_MAGIC);
- m = (unsigned long)first_page->mapping;
- *fullness = m & FULLNESS_MASK;
- *class_idx = (m >> FULLNESS_BITS) & CLASS_IDX_MASK;
+ *fullness = zspage->fullness;
+ *class_idx = zspage->class;
}
-static void set_zspage_mapping(struct page *first_page,
+static void set_zspage_mapping(struct zspage *zspage,
unsigned int class_idx,
enum fullness_group fullness)
{
- unsigned long m;
- VM_BUG_ON_PAGE(!is_first_page(first_page), first_page);
-
- m = ((class_idx & CLASS_IDX_MASK) << FULLNESS_BITS) |
- (fullness & FULLNESS_MASK);
- first_page->mapping = (struct address_space *)m;
+ zspage->class = class_idx;
+ zspage->fullness = fullness;
}
/*
static inline void zs_stat_inc(struct size_class *class,
enum zs_stat_type type, unsigned long cnt)
{
- if (type < NR_ZS_STAT_TYPE)
- class->stats.objs[type] += cnt;
+ class->stats.objs[type] += cnt;
}
static inline void zs_stat_dec(struct size_class *class,
enum zs_stat_type type, unsigned long cnt)
{
- if (type < NR_ZS_STAT_TYPE)
- class->stats.objs[type] -= cnt;
+ class->stats.objs[type] -= cnt;
}
static inline unsigned long zs_stat_get(struct size_class *class,
enum zs_stat_type type)
{
- if (type < NR_ZS_STAT_TYPE)
- return class->stats.objs[type];
- return 0;
+ return class->stats.objs[type];
}
#ifdef CONFIG_ZSMALLOC_STAT
freeable = zs_can_compact(class);
spin_unlock(&class->lock);
- objs_per_zspage = get_maxobj_per_zspage(class->size,
- class->pages_per_zspage);
+ objs_per_zspage = class->objs_per_zspage;
pages_used = obj_allocated / objs_per_zspage *
class->pages_per_zspage;
}
#endif
+
/*
* For each size class, zspages are divided into different groups
* depending on how "full" they are. This was done so that we could
* status of the given page.
*/
static enum fullness_group get_fullness_group(struct size_class *class,
- struct page *first_page)
+ struct zspage *zspage)
{
int inuse, objs_per_zspage;
enum fullness_group fg;
- VM_BUG_ON_PAGE(!is_first_page(first_page), first_page);
-
- inuse = first_page->inuse;
+ inuse = get_zspage_inuse(zspage);
objs_per_zspage = class->objs_per_zspage;
if (inuse == 0)
* identified by <class, fullness_group>.
*/
static void insert_zspage(struct size_class *class,
- enum fullness_group fullness,
- struct page *first_page)
+ struct zspage *zspage,
+ enum fullness_group fullness)
{
- struct page **head;
-
- VM_BUG_ON_PAGE(!is_first_page(first_page), first_page);
-
- if (fullness >= _ZS_NR_FULLNESS_GROUPS)
- return;
-
- zs_stat_inc(class, fullness == ZS_ALMOST_EMPTY ?
- CLASS_ALMOST_EMPTY : CLASS_ALMOST_FULL, 1);
-
- head = &class->fullness_list[fullness];
- if (!*head) {
- *head = first_page;
- return;
- }
+ struct zspage *head;
+ zs_stat_inc(class, fullness, 1);
+ head = list_first_entry_or_null(&class->fullness_list[fullness],
+ struct zspage, list);
/*
- * We want to see more ZS_FULL pages and less almost
- * empty/full. Put pages with higher ->inuse first.
+ * We want to see more ZS_FULL pages and less almost empty/full.
+ * Put pages with higher ->inuse first.
*/
- list_add_tail(&first_page->lru, &(*head)->lru);
- if (first_page->inuse >= (*head)->inuse)
- *head = first_page;
+ if (head) {
+ if (get_zspage_inuse(zspage) < get_zspage_inuse(head)) {
+ list_add(&zspage->list, &head->list);
+ return;
+ }
+ }
+ list_add(&zspage->list, &class->fullness_list[fullness]);
}
/*
* by <class, fullness_group>.
*/
static void remove_zspage(struct size_class *class,
- enum fullness_group fullness,
- struct page *first_page)
+ struct zspage *zspage,
+ enum fullness_group fullness)
{
- struct page **head;
-
- VM_BUG_ON_PAGE(!is_first_page(first_page), first_page);
-
- if (fullness >= _ZS_NR_FULLNESS_GROUPS)
- return;
+ VM_BUG_ON(list_empty(&class->fullness_list[fullness]));
+ VM_BUG_ON(is_zspage_isolated(zspage));
- head = &class->fullness_list[fullness];
- VM_BUG_ON_PAGE(!*head, first_page);
- if (list_empty(&(*head)->lru))
- *head = NULL;
- else if (*head == first_page)
- *head = (struct page *)list_entry((*head)->lru.next,
- struct page, lru);
-
- list_del_init(&first_page->lru);
- zs_stat_dec(class, fullness == ZS_ALMOST_EMPTY ?
- CLASS_ALMOST_EMPTY : CLASS_ALMOST_FULL, 1);
+ list_del_init(&zspage->list);
+ zs_stat_dec(class, fullness, 1);
}
/*
* fullness group.
*/
static enum fullness_group fix_fullness_group(struct size_class *class,
- struct page *first_page)
+ struct zspage *zspage)
{
int class_idx;
enum fullness_group currfg, newfg;
- get_zspage_mapping(first_page, &class_idx, &currfg);
- newfg = get_fullness_group(class, first_page);
+ get_zspage_mapping(zspage, &class_idx, &currfg);
+ newfg = get_fullness_group(class, zspage);
if (newfg == currfg)
goto out;
- remove_zspage(class, currfg, first_page);
- insert_zspage(class, newfg, first_page);
- set_zspage_mapping(first_page, class_idx, newfg);
+ if (!is_zspage_isolated(zspage)) {
+ remove_zspage(class, zspage, currfg);
+ insert_zspage(class, zspage, newfg);
+ }
+
+ set_zspage_mapping(zspage, class_idx, newfg);
out:
return newfg;
return max_usedpc_order;
}
-/*
- * A single 'zspage' is composed of many system pages which are
- * linked together using fields in struct page. This function finds
- * the first/head page, given any component page of a zspage.
- */
-static struct page *get_first_page(struct page *page)
+static struct zspage *get_zspage(struct page *page)
{
- if (is_first_page(page))
- return page;
- else
- return (struct page *)page_private(page);
+ struct zspage *zspage = (struct zspage *)page->private;
+
+ BUG_ON(zspage->magic != ZSPAGE_MAGIC);
+ return zspage;
}
static struct page *get_next_page(struct page *page)
{
- struct page *next;
+ if (unlikely(PageHugeObject(page)))
+ return NULL;
- if (is_last_page(page))
- next = NULL;
- else if (is_first_page(page))
- next = (struct page *)page_private(page);
- else
- next = list_entry(page->lru.next, struct page, lru);
+ return page->freelist;
+}
- return next;
+/**
+ * obj_to_location - get (<page>, <obj_idx>) from encoded object value
+ * @page: page object resides in zspage
+ * @obj_idx: object index
+ */
+static void obj_to_location(unsigned long obj, struct page **page,
+ unsigned int *obj_idx)
+{
+ obj >>= OBJ_TAG_BITS;
+ *page = pfn_to_page(obj >> OBJ_INDEX_BITS);
+ *obj_idx = (obj & OBJ_INDEX_MASK);
}
-/*
- * Encode <page, obj_idx> as a single handle value.
- * We use the least bit of handle for tagging.
+/**
+ * location_to_obj - get obj value encoded from (<page>, <obj_idx>)
+ * @page: page object resides in zspage
+ * @obj_idx: object index
*/
-static void *location_to_obj(struct page *page, unsigned long obj_idx)
+static unsigned long location_to_obj(struct page *page, unsigned int obj_idx)
{
unsigned long obj;
- if (!page) {
- VM_BUG_ON(obj_idx);
- return NULL;
- }
-
obj = page_to_pfn(page) << OBJ_INDEX_BITS;
- obj |= ((obj_idx) & OBJ_INDEX_MASK);
+ obj |= obj_idx & OBJ_INDEX_MASK;
obj <<= OBJ_TAG_BITS;
- return (void *)obj;
-}
-
-/*
- * Decode <page, obj_idx> pair from the given object handle. We adjust the
- * decoded obj_idx back to its original value since it was adjusted in
- * location_to_obj().
- */
-static void obj_to_location(unsigned long obj, struct page **page,
- unsigned long *obj_idx)
-{
- obj >>= OBJ_TAG_BITS;
- *page = pfn_to_page(obj >> OBJ_INDEX_BITS);
- *obj_idx = (obj & OBJ_INDEX_MASK);
+ return obj;
}
static unsigned long handle_to_obj(unsigned long handle)
return *(unsigned long *)handle;
}
-static unsigned long obj_to_head(struct size_class *class, struct page *page,
- void *obj)
+static unsigned long obj_to_head(struct page *page, void *obj)
{
- if (class->huge) {
+ if (unlikely(PageHugeObject(page))) {
VM_BUG_ON_PAGE(!is_first_page(page), page);
- return page_private(page);
+ return page->index;
} else
return *(unsigned long *)obj;
}
-static unsigned long obj_idx_to_offset(struct page *page,
- unsigned long obj_idx, int class_size)
+static inline int testpin_tag(unsigned long handle)
{
- unsigned long off = 0;
-
- if (!is_first_page(page))
- off = page->index;
-
- return off + obj_idx * class_size;
+ return bit_spin_is_locked(HANDLE_PIN_BIT, (unsigned long *)handle);
}
static inline int trypin_tag(unsigned long handle)
{
- unsigned long *ptr = (unsigned long *)handle;
-
- return !test_and_set_bit_lock(HANDLE_PIN_BIT, ptr);
+ return bit_spin_trylock(HANDLE_PIN_BIT, (unsigned long *)handle);
}
static void pin_tag(unsigned long handle)
{
- while (!trypin_tag(handle));
+ bit_spin_lock(HANDLE_PIN_BIT, (unsigned long *)handle);
}
static void unpin_tag(unsigned long handle)
{
- unsigned long *ptr = (unsigned long *)handle;
-
- clear_bit_unlock(HANDLE_PIN_BIT, ptr);
+ bit_spin_unlock(HANDLE_PIN_BIT, (unsigned long *)handle);
}
static void reset_page(struct page *page)
{
- clear_bit(PG_private, &page->flags);
- clear_bit(PG_private_2, &page->flags);
+ __ClearPageMovable(page);
+ ClearPagePrivate(page);
+ ClearPagePrivate2(page);
set_page_private(page, 0);
- page->mapping = NULL;
- page->freelist = NULL;
page_mapcount_reset(page);
+ ClearPageHugeObject(page);
+ page->freelist = NULL;
}
-static void free_zspage(struct page *first_page)
+/*
+ * To prevent zspage destroy during migration, zspage freeing should
+ * hold locks of all pages in the zspage.
+ */
+void lock_zspage(struct zspage *zspage)
{
- struct page *nextp, *tmp, *head_extra;
+ struct page *page = get_first_page(zspage);
- VM_BUG_ON_PAGE(!is_first_page(first_page), first_page);
- VM_BUG_ON_PAGE(first_page->inuse, first_page);
+ do {
+ lock_page(page);
+ } while ((page = get_next_page(page)) != NULL);
+}
- head_extra = (struct page *)page_private(first_page);
+int trylock_zspage(struct zspage *zspage)
+{
+ struct page *cursor, *fail;
- reset_page(first_page);
- __free_page(first_page);
+ for (cursor = get_first_page(zspage); cursor != NULL; cursor =
+ get_next_page(cursor)) {
+ if (!trylock_page(cursor)) {
+ fail = cursor;
+ goto unlock;
+ }
+ }
- /* zspage with only 1 system page */
- if (!head_extra)
- return;
+ return 1;
+unlock:
+ for (cursor = get_first_page(zspage); cursor != fail; cursor =
+ get_next_page(cursor))
+ unlock_page(cursor);
+
+ return 0;
+}
+
+static void __free_zspage(struct zs_pool *pool, struct size_class *class,
+ struct zspage *zspage)
+{
+ struct page *page, *next;
+ enum fullness_group fg;
+ unsigned int class_idx;
- list_for_each_entry_safe(nextp, tmp, &head_extra->lru, lru) {
- list_del(&nextp->lru);
- reset_page(nextp);
- __free_page(nextp);
+ get_zspage_mapping(zspage, &class_idx, &fg);
+
+ assert_spin_locked(&class->lock);
+
+ VM_BUG_ON(get_zspage_inuse(zspage));
+ VM_BUG_ON(fg != ZS_EMPTY);
+
+ next = page = get_first_page(zspage);
+ do {
+ VM_BUG_ON_PAGE(!PageLocked(page), page);
+ next = get_next_page(page);
+ reset_page(page);
+ unlock_page(page);
+ dec_zone_page_state(page, NR_ZSPAGES);
+ put_page(page);
+ page = next;
+ } while (page != NULL);
+
+ cache_free_zspage(pool, zspage);
+
+ zs_stat_dec(class, OBJ_ALLOCATED, class->objs_per_zspage);
+ atomic_long_sub(class->pages_per_zspage,
+ &pool->pages_allocated);
+}
+
+static void free_zspage(struct zs_pool *pool, struct size_class *class,
+ struct zspage *zspage)
+{
+ VM_BUG_ON(get_zspage_inuse(zspage));
+ VM_BUG_ON(list_empty(&zspage->list));
+
+ if (!trylock_zspage(zspage)) {
+ kick_deferred_free(pool);
+ return;
}
- reset_page(head_extra);
- __free_page(head_extra);
+
+ remove_zspage(class, zspage, ZS_EMPTY);
+ __free_zspage(pool, class, zspage);
}
/* Initialize a newly allocated zspage */
-static void init_zspage(struct size_class *class, struct page *first_page)
+static void init_zspage(struct size_class *class, struct zspage *zspage)
{
+ unsigned int freeobj = 1;
unsigned long off = 0;
- struct page *page = first_page;
-
- VM_BUG_ON_PAGE(!is_first_page(first_page), first_page);
+ struct page *page = get_first_page(zspage);
while (page) {
struct page *next_page;
struct link_free *link;
- unsigned int i = 1;
void *vaddr;
- /*
- * page->index stores offset of first object starting
- * in the page. For the first page, this is always 0,
- * so we use first_page->index (aka ->freelist) to store
- * head of corresponding zspage's freelist.
- */
- if (page != first_page)
- page->index = off;
+ set_first_obj_offset(page, off);
vaddr = kmap_atomic(page);
link = (struct link_free *)vaddr + off / sizeof(*link);
while ((off += class->size) < PAGE_SIZE) {
- link->next = location_to_obj(page, i++);
+ link->next = freeobj++ << OBJ_TAG_BITS;
link += class->size / sizeof(*link);
}
* page (if present)
*/
next_page = get_next_page(page);
- link->next = location_to_obj(next_page, 0);
+ if (next_page) {
+ link->next = freeobj++ << OBJ_TAG_BITS;
+ } else {
+ /*
+ * Reset OBJ_TAG_BITS bit to last link to tell
+ * whether it's allocated object or not.
+ */
+ link->next = -1 << OBJ_TAG_BITS;
+ }
kunmap_atomic(vaddr);
page = next_page;
off %= PAGE_SIZE;
}
+
+ set_freeobj(zspage, 0);
}
-/*
- * Allocate a zspage for the given size class
- */
-static struct page *alloc_zspage(struct size_class *class, gfp_t flags)
+static void create_page_chain(struct size_class *class, struct zspage *zspage,
+ struct page *pages[])
{
- int i, error;
- struct page *first_page = NULL, *uninitialized_var(prev_page);
+ int i;
+ struct page *page;
+ struct page *prev_page = NULL;
+ int nr_pages = class->pages_per_zspage;
/*
* Allocate individual pages and link them together as:
- * 1. first page->private = first sub-page
- * 2. all sub-pages are linked together using page->lru
- * 3. each sub-page is linked to the first page using page->private
+ * 1. all pages are linked together using page->freelist
+ * 2. each sub-page point to zspage using page->private
*
- * For each size class, First/Head pages are linked together using
- * page->lru. Also, we set PG_private to identify the first page
- * (i.e. no other sub-page has this flag set) and PG_private_2 to
- * identify the last page.
+ * we set PG_private to identify the first page (i.e. no other sub-page
+ * has this flag set) and PG_private_2 to identify the last page.
*/
- error = -ENOMEM;
- for (i = 0; i < class->pages_per_zspage; i++) {
- struct page *page;
-
- page = alloc_page(flags);
- if (!page)
- goto cleanup;
-
- INIT_LIST_HEAD(&page->lru);
- if (i == 0) { /* first page */
+ for (i = 0; i < nr_pages; i++) {
+ page = pages[i];
+ set_page_private(page, (unsigned long)zspage);
+ page->freelist = NULL;
+ if (i == 0) {
+ zspage->first_page = page;
SetPagePrivate(page);
- set_page_private(page, 0);
- first_page = page;
- first_page->inuse = 0;
+ if (unlikely(class->objs_per_zspage == 1 &&
+ class->pages_per_zspage == 1))
+ SetPageHugeObject(page);
+ } else {
+ prev_page->freelist = page;
}
- if (i == 1)
- set_page_private(first_page, (unsigned long)page);
- if (i >= 1)
- set_page_private(page, (unsigned long)first_page);
- if (i >= 2)
- list_add(&page->lru, &prev_page->lru);
- if (i == class->pages_per_zspage - 1) /* last page */
+ if (i == nr_pages - 1)
SetPagePrivate2(page);
prev_page = page;
}
+}
- init_zspage(class, first_page);
+/*
+ * Allocate a zspage for the given size class
+ */
+static struct zspage *alloc_zspage(struct zs_pool *pool,
+ struct size_class *class,
+ gfp_t gfp)
+{
+ int i;
+ struct page *pages[ZS_MAX_PAGES_PER_ZSPAGE];
+ struct zspage *zspage = cache_alloc_zspage(pool, gfp);
+
+ if (!zspage)
+ return NULL;
+
+ memset(zspage, 0, sizeof(struct zspage));
+ zspage->magic = ZSPAGE_MAGIC;
+ migrate_lock_init(zspage);
+
+ for (i = 0; i < class->pages_per_zspage; i++) {
+ struct page *page;
- first_page->freelist = location_to_obj(first_page, 0);
- error = 0; /* Success */
+ page = alloc_page(gfp);
+ if (!page) {
+ while (--i >= 0) {
+ dec_zone_page_state(pages[i], NR_ZSPAGES);
+ __free_page(pages[i]);
+ }
+ cache_free_zspage(pool, zspage);
+ return NULL;
+ }
-cleanup:
- if (unlikely(error) && first_page) {
- free_zspage(first_page);
- first_page = NULL;
+ inc_zone_page_state(page, NR_ZSPAGES);
+ pages[i] = page;
}
- return first_page;
+ create_page_chain(class, zspage, pages);
+ init_zspage(class, zspage);
+
+ return zspage;
}
-static struct page *find_get_zspage(struct size_class *class)
+static struct zspage *find_get_zspage(struct size_class *class)
{
int i;
- struct page *page;
+ struct zspage *zspage;
- for (i = 0; i < _ZS_NR_FULLNESS_GROUPS; i++) {
- page = class->fullness_list[i];
- if (page)
+ for (i = ZS_ALMOST_FULL; i >= ZS_EMPTY; i--) {
+ zspage = list_first_entry_or_null(&class->fullness_list[i],
+ struct zspage, list);
+ if (zspage)
break;
}
- return page;
+ return zspage;
}
#ifdef CONFIG_PGTABLE_MAPPING
cpu_notifier_register_done();
}
-static void init_zs_size_classes(void)
+static void __init init_zs_size_classes(void)
{
int nr;
zs_size_classes = nr;
}
-static bool can_merge(struct size_class *prev, int size, int pages_per_zspage)
+static bool can_merge(struct size_class *prev, int pages_per_zspage,
+ int objs_per_zspage)
{
- if (prev->pages_per_zspage != pages_per_zspage)
- return false;
+ if (prev->pages_per_zspage == pages_per_zspage &&
+ prev->objs_per_zspage == objs_per_zspage)
+ return true;
- if (get_maxobj_per_zspage(prev->size, prev->pages_per_zspage)
- != get_maxobj_per_zspage(size, pages_per_zspage))
- return false;
-
- return true;
+ return false;
}
-static bool zspage_full(struct size_class *class, struct page *first_page)
+static bool zspage_full(struct size_class *class, struct zspage *zspage)
{
- VM_BUG_ON_PAGE(!is_first_page(first_page), first_page);
-
- return first_page->inuse == class->objs_per_zspage;
+ return get_zspage_inuse(zspage) == class->objs_per_zspage;
}
unsigned long zs_get_total_pages(struct zs_pool *pool)
void *zs_map_object(struct zs_pool *pool, unsigned long handle,
enum zs_mapmode mm)
{
+ struct zspage *zspage;
struct page *page;
- unsigned long obj, obj_idx, off;
+ unsigned long obj, off;
+ unsigned int obj_idx;
unsigned int class_idx;
enum fullness_group fg;
obj = handle_to_obj(handle);
obj_to_location(obj, &page, &obj_idx);
- get_zspage_mapping(get_first_page(page), &class_idx, &fg);
+ zspage = get_zspage(page);
+
+ /* migration cannot move any subpage in this zspage */
+ migrate_read_lock(zspage);
+
+ get_zspage_mapping(zspage, &class_idx, &fg);
class = pool->size_class[class_idx];
- off = obj_idx_to_offset(page, obj_idx, class->size);
+ off = (class->size * obj_idx) & ~PAGE_MASK;
area = &get_cpu_var(zs_map_area);
area->vm_mm = mm;
ret = __zs_map_object(area, pages, off, class->size);
out:
- if (!class->huge)
+ if (likely(!PageHugeObject(page)))
ret += ZS_HANDLE_SIZE;
return ret;
void zs_unmap_object(struct zs_pool *pool, unsigned long handle)
{
+ struct zspage *zspage;
struct page *page;
- unsigned long obj, obj_idx, off;
+ unsigned long obj, off;
+ unsigned int obj_idx;
unsigned int class_idx;
enum fullness_group fg;
obj = handle_to_obj(handle);
obj_to_location(obj, &page, &obj_idx);
- get_zspage_mapping(get_first_page(page), &class_idx, &fg);
+ zspage = get_zspage(page);
+ get_zspage_mapping(zspage, &class_idx, &fg);
class = pool->size_class[class_idx];
- off = obj_idx_to_offset(page, obj_idx, class->size);
+ off = (class->size * obj_idx) & ~PAGE_MASK;
area = this_cpu_ptr(&zs_map_area);
if (off + class->size <= PAGE_SIZE)
__zs_unmap_object(area, pages, off, class->size);
}
put_cpu_var(zs_map_area);
+
+ migrate_read_unlock(zspage);
unpin_tag(handle);
}
EXPORT_SYMBOL_GPL(zs_unmap_object);
static unsigned long obj_malloc(struct size_class *class,
- struct page *first_page, unsigned long handle)
+ struct zspage *zspage, unsigned long handle)
{
+ int i, nr_page, offset;
unsigned long obj;
struct link_free *link;
struct page *m_page;
- unsigned long m_objidx, m_offset;
+ unsigned long m_offset;
void *vaddr;
handle |= OBJ_ALLOCATED_TAG;
- obj = (unsigned long)first_page->freelist;
- obj_to_location(obj, &m_page, &m_objidx);
- m_offset = obj_idx_to_offset(m_page, m_objidx, class->size);
+ obj = get_freeobj(zspage);
+
+ offset = obj * class->size;
+ nr_page = offset >> PAGE_SHIFT;
+ m_offset = offset & ~PAGE_MASK;
+ m_page = get_first_page(zspage);
+
+ for (i = 0; i < nr_page; i++)
+ m_page = get_next_page(m_page);
vaddr = kmap_atomic(m_page);
link = (struct link_free *)vaddr + m_offset / sizeof(*link);
- first_page->freelist = link->next;
- if (!class->huge)
+ set_freeobj(zspage, link->next >> OBJ_TAG_BITS);
+ if (likely(!PageHugeObject(m_page)))
/* record handle in the header of allocated chunk */
link->handle = handle;
else
- /* record handle in first_page->private */
- set_page_private(first_page, handle);
+ /* record handle to page->index */
+ zspage->first_page->index = handle;
+
kunmap_atomic(vaddr);
- first_page->inuse++;
+ mod_zspage_inuse(zspage, 1);
zs_stat_inc(class, OBJ_USED, 1);
+ obj = location_to_obj(m_page, obj);
+
return obj;
}
* zs_malloc - Allocate block of given size from pool.
* @pool: pool to allocate from
* @size: size of block to allocate
+ * @gfp: gfp flags when allocating object
*
* On success, handle to the allocated object is returned,
* otherwise 0.
{
unsigned long handle, obj;
struct size_class *class;
- struct page *first_page;
+ enum fullness_group newfg;
+ struct zspage *zspage;
if (unlikely(!size || size > ZS_MAX_ALLOC_SIZE))
return 0;
- handle = alloc_handle(pool, gfp);
+ handle = cache_alloc_handle(pool, gfp);
if (!handle)
return 0;
class = pool->size_class[get_size_class_index(size)];
spin_lock(&class->lock);
- first_page = find_get_zspage(class);
-
- if (!first_page) {
+ zspage = find_get_zspage(class);
+ if (likely(zspage)) {
+ obj = obj_malloc(class, zspage, handle);
+ /* Now move the zspage to another fullness group, if required */
+ fix_fullness_group(class, zspage);
+ record_obj(handle, obj);
spin_unlock(&class->lock);
- first_page = alloc_zspage(class, gfp);
- if (unlikely(!first_page)) {
- free_handle(pool, handle);
- return 0;
- }
- set_zspage_mapping(first_page, class->index, ZS_EMPTY);
- atomic_long_add(class->pages_per_zspage,
- &pool->pages_allocated);
+ return handle;
+ }
- spin_lock(&class->lock);
- zs_stat_inc(class, OBJ_ALLOCATED, get_maxobj_per_zspage(
- class->size, class->pages_per_zspage));
+ spin_unlock(&class->lock);
+
+ zspage = alloc_zspage(pool, class, gfp);
+ if (!zspage) {
+ cache_free_handle(pool, handle);
+ return 0;
}
- obj = obj_malloc(class, first_page, handle);
- /* Now move the zspage to another fullness group, if required */
- fix_fullness_group(class, first_page);
+ spin_lock(&class->lock);
+ obj = obj_malloc(class, zspage, handle);
+ newfg = get_fullness_group(class, zspage);
+ insert_zspage(class, zspage, newfg);
+ set_zspage_mapping(zspage, class->index, newfg);
record_obj(handle, obj);
+ atomic_long_add(class->pages_per_zspage,
+ &pool->pages_allocated);
+ zs_stat_inc(class, OBJ_ALLOCATED, class->objs_per_zspage);
+
+ /* We completely set up zspage so mark them as movable */
+ SetZsPageMovable(pool, zspage);
spin_unlock(&class->lock);
return handle;
static void obj_free(struct size_class *class, unsigned long obj)
{
struct link_free *link;
- struct page *first_page, *f_page;
- unsigned long f_objidx, f_offset;
+ struct zspage *zspage;
+ struct page *f_page;
+ unsigned long f_offset;
+ unsigned int f_objidx;
void *vaddr;
obj &= ~OBJ_ALLOCATED_TAG;
obj_to_location(obj, &f_page, &f_objidx);
- first_page = get_first_page(f_page);
-
- f_offset = obj_idx_to_offset(f_page, f_objidx, class->size);
+ f_offset = (class->size * f_objidx) & ~PAGE_MASK;
+ zspage = get_zspage(f_page);
vaddr = kmap_atomic(f_page);
/* Insert this object in containing zspage's freelist */
link = (struct link_free *)(vaddr + f_offset);
- link->next = first_page->freelist;
- if (class->huge)
- set_page_private(first_page, 0);
+ link->next = get_freeobj(zspage) << OBJ_TAG_BITS;
kunmap_atomic(vaddr);
- first_page->freelist = (void *)obj;
- first_page->inuse--;
+ set_freeobj(zspage, f_objidx);
+ mod_zspage_inuse(zspage, -1);
zs_stat_dec(class, OBJ_USED, 1);
}
void zs_free(struct zs_pool *pool, unsigned long handle)
{
- struct page *first_page, *f_page;
- unsigned long obj, f_objidx;
+ struct zspage *zspage;
+ struct page *f_page;
+ unsigned long obj;
+ unsigned int f_objidx;
int class_idx;
struct size_class *class;
enum fullness_group fullness;
+ bool isolated;
if (unlikely(!handle))
return;
pin_tag(handle);
obj = handle_to_obj(handle);
obj_to_location(obj, &f_page, &f_objidx);
- first_page = get_first_page(f_page);
+ zspage = get_zspage(f_page);
+
+ migrate_read_lock(zspage);
- get_zspage_mapping(first_page, &class_idx, &fullness);
+ get_zspage_mapping(zspage, &class_idx, &fullness);
class = pool->size_class[class_idx];
spin_lock(&class->lock);
obj_free(class, obj);
- fullness = fix_fullness_group(class, first_page);
- if (fullness == ZS_EMPTY) {
- zs_stat_dec(class, OBJ_ALLOCATED, get_maxobj_per_zspage(
- class->size, class->pages_per_zspage));
- atomic_long_sub(class->pages_per_zspage,
- &pool->pages_allocated);
- free_zspage(first_page);
+ fullness = fix_fullness_group(class, zspage);
+ if (fullness != ZS_EMPTY) {
+ migrate_read_unlock(zspage);
+ goto out;
}
+
+ isolated = is_zspage_isolated(zspage);
+ migrate_read_unlock(zspage);
+ /* If zspage is isolated, zs_page_putback will free the zspage */
+ if (likely(!isolated))
+ free_zspage(pool, class, zspage);
+out:
+
spin_unlock(&class->lock);
unpin_tag(handle);
-
- free_handle(pool, handle);
+ cache_free_handle(pool, handle);
}
EXPORT_SYMBOL_GPL(zs_free);
unsigned long src)
{
struct page *s_page, *d_page;
- unsigned long s_objidx, d_objidx;
+ unsigned int s_objidx, d_objidx;
unsigned long s_off, d_off;
void *s_addr, *d_addr;
int s_size, d_size, size;
obj_to_location(src, &s_page, &s_objidx);
obj_to_location(dst, &d_page, &d_objidx);
- s_off = obj_idx_to_offset(s_page, s_objidx, class->size);
- d_off = obj_idx_to_offset(d_page, d_objidx, class->size);
+ s_off = (class->size * s_objidx) & ~PAGE_MASK;
+ d_off = (class->size * d_objidx) & ~PAGE_MASK;
if (s_off + class->size > PAGE_SIZE)
s_size = PAGE_SIZE - s_off;
* return handle.
*/
static unsigned long find_alloced_obj(struct size_class *class,
- struct page *page, int index)
+ struct page *page, int *obj_idx)
{
unsigned long head;
int offset = 0;
+ int index = *obj_idx;
unsigned long handle = 0;
void *addr = kmap_atomic(page);
- if (!is_first_page(page))
- offset = page->index;
+ offset = get_first_obj_offset(page);
offset += class->size * index;
while (offset < PAGE_SIZE) {
- head = obj_to_head(class, page, addr + offset);
+ head = obj_to_head(page, addr + offset);
if (head & OBJ_ALLOCATED_TAG) {
handle = head & ~OBJ_ALLOCATED_TAG;
if (trypin_tag(handle))
}
kunmap_atomic(addr);
+
+ *obj_idx = index;
+
return handle;
}
struct zs_compact_control {
- /* Source page for migration which could be a subpage of zspage. */
+ /* Source spage for migration which could be a subpage of zspage */
struct page *s_page;
/* Destination page for migration which should be a first page
* of zspage. */
struct page *d_page;
/* Starting object index within @s_page which used for live object
* in the subpage. */
- int index;
+ int obj_idx;
};
static int migrate_zspage(struct zs_pool *pool, struct size_class *class,
unsigned long handle;
struct page *s_page = cc->s_page;
struct page *d_page = cc->d_page;
- unsigned long index = cc->index;
+ int obj_idx = cc->obj_idx;
int ret = 0;
while (1) {
- handle = find_alloced_obj(class, s_page, index);
+ handle = find_alloced_obj(class, s_page, &obj_idx);
if (!handle) {
s_page = get_next_page(s_page);
if (!s_page)
break;
- index = 0;
+ obj_idx = 0;
continue;
}
/* Stop if there is no more space */
- if (zspage_full(class, d_page)) {
+ if (zspage_full(class, get_zspage(d_page))) {
unpin_tag(handle);
ret = -ENOMEM;
break;
}
used_obj = handle_to_obj(handle);
- free_obj = obj_malloc(class, d_page, handle);
+ free_obj = obj_malloc(class, get_zspage(d_page), handle);
zs_object_copy(class, free_obj, used_obj);
- index++;
+ obj_idx++;
/*
* record_obj updates handle's value to free_obj and it will
* invalidate lock bit(ie, HANDLE_PIN_BIT) of handle, which
/* Remember last position in this iteration */
cc->s_page = s_page;
- cc->index = index;
+ cc->obj_idx = obj_idx;
return ret;
}
-static struct page *isolate_target_page(struct size_class *class)
+static struct zspage *isolate_zspage(struct size_class *class, bool source)
{
int i;
- struct page *page;
+ struct zspage *zspage;
+ enum fullness_group fg[2] = {ZS_ALMOST_EMPTY, ZS_ALMOST_FULL};
- for (i = 0; i < _ZS_NR_FULLNESS_GROUPS; i++) {
- page = class->fullness_list[i];
- if (page) {
- remove_zspage(class, i, page);
- break;
+ if (!source) {
+ fg[0] = ZS_ALMOST_FULL;
+ fg[1] = ZS_ALMOST_EMPTY;
+ }
+
+ for (i = 0; i < 2; i++) {
+ zspage = list_first_entry_or_null(&class->fullness_list[fg[i]],
+ struct zspage, list);
+ if (zspage) {
+ VM_BUG_ON(is_zspage_isolated(zspage));
+ remove_zspage(class, zspage, fg[i]);
+ return zspage;
}
}
- return page;
+ return zspage;
}
/*
- * putback_zspage - add @first_page into right class's fullness list
- * @pool: target pool
+ * putback_zspage - add @zspage into right class's fullness list
* @class: destination class
- * @first_page: target page
+ * @zspage: target page
*
- * Return @fist_page's fullness_group
+ * Return @zspage's fullness_group
*/
-static enum fullness_group putback_zspage(struct zs_pool *pool,
- struct size_class *class,
- struct page *first_page)
+static enum fullness_group putback_zspage(struct size_class *class,
+ struct zspage *zspage)
{
enum fullness_group fullness;
- fullness = get_fullness_group(class, first_page);
- insert_zspage(class, fullness, first_page);
- set_zspage_mapping(first_page, class->index, fullness);
+ VM_BUG_ON(is_zspage_isolated(zspage));
- if (fullness == ZS_EMPTY) {
- zs_stat_dec(class, OBJ_ALLOCATED, get_maxobj_per_zspage(
- class->size, class->pages_per_zspage));
- atomic_long_sub(class->pages_per_zspage,
- &pool->pages_allocated);
+ fullness = get_fullness_group(class, zspage);
+ insert_zspage(class, zspage, fullness);
+ set_zspage_mapping(zspage, class->index, fullness);
+
+ return fullness;
+}
+
+#ifdef CONFIG_COMPACTION
+static struct dentry *zs_mount(struct file_system_type *fs_type,
+ int flags, const char *dev_name, void *data)
+{
+ static const struct dentry_operations ops = {
+ .d_dname = simple_dname,
+ };
- free_zspage(first_page);
+ return mount_pseudo(fs_type, "zsmalloc:", NULL, &ops, ZSMALLOC_MAGIC);
+}
+
+static struct file_system_type zsmalloc_fs = {
+ .name = "zsmalloc",
+ .mount = zs_mount,
+ .kill_sb = kill_anon_super,
+};
+
+static int zsmalloc_mount(void)
+{
+ int ret = 0;
+
+ zsmalloc_mnt = kern_mount(&zsmalloc_fs);
+ if (IS_ERR(zsmalloc_mnt))
+ ret = PTR_ERR(zsmalloc_mnt);
+
+ return ret;
+}
+
+static void zsmalloc_unmount(void)
+{
+ kern_unmount(zsmalloc_mnt);
+}
+
+static void migrate_lock_init(struct zspage *zspage)
+{
+ rwlock_init(&zspage->lock);
+}
+
+static void migrate_read_lock(struct zspage *zspage)
+{
+ read_lock(&zspage->lock);
+}
+
+static void migrate_read_unlock(struct zspage *zspage)
+{
+ read_unlock(&zspage->lock);
+}
+
+static void migrate_write_lock(struct zspage *zspage)
+{
+ write_lock(&zspage->lock);
+}
+
+static void migrate_write_unlock(struct zspage *zspage)
+{
+ write_unlock(&zspage->lock);
+}
+
+/* Number of isolated subpage for *page migration* in this zspage */
+static void inc_zspage_isolation(struct zspage *zspage)
+{
+ zspage->isolated++;
+}
+
+static void dec_zspage_isolation(struct zspage *zspage)
+{
+ zspage->isolated--;
+}
+
+static void replace_sub_page(struct size_class *class, struct zspage *zspage,
+ struct page *newpage, struct page *oldpage)
+{
+ struct page *page;
+ struct page *pages[ZS_MAX_PAGES_PER_ZSPAGE] = {NULL, };
+ int idx = 0;
+
+ page = get_first_page(zspage);
+ do {
+ if (page == oldpage)
+ pages[idx] = newpage;
+ else
+ pages[idx] = page;
+ idx++;
+ } while ((page = get_next_page(page)) != NULL);
+
+ create_page_chain(class, zspage, pages);
+ set_first_obj_offset(newpage, get_first_obj_offset(oldpage));
+ if (unlikely(PageHugeObject(oldpage)))
+ newpage->index = oldpage->index;
+ __SetPageMovable(newpage, page_mapping(oldpage));
+}
+
+bool zs_page_isolate(struct page *page, isolate_mode_t mode)
+{
+ struct zs_pool *pool;
+ struct size_class *class;
+ int class_idx;
+ enum fullness_group fullness;
+ struct zspage *zspage;
+ struct address_space *mapping;
+
+ /*
+ * Page is locked so zspage couldn't be destroyed. For detail, look at
+ * lock_zspage in free_zspage.
+ */
+ VM_BUG_ON_PAGE(!PageMovable(page), page);
+ VM_BUG_ON_PAGE(PageIsolated(page), page);
+
+ zspage = get_zspage(page);
+
+ /*
+ * Without class lock, fullness could be stale while class_idx is okay
+ * because class_idx is constant unless page is freed so we should get
+ * fullness again under class lock.
+ */
+ get_zspage_mapping(zspage, &class_idx, &fullness);
+ mapping = page_mapping(page);
+ pool = mapping->private_data;
+ class = pool->size_class[class_idx];
+
+ spin_lock(&class->lock);
+ if (get_zspage_inuse(zspage) == 0) {
+ spin_unlock(&class->lock);
+ return false;
}
- return fullness;
+ /* zspage is isolated for object migration */
+ if (list_empty(&zspage->list) && !is_zspage_isolated(zspage)) {
+ spin_unlock(&class->lock);
+ return false;
+ }
+
+ /*
+ * If this is first time isolation for the zspage, isolate zspage from
+ * size_class to prevent further object allocation from the zspage.
+ */
+ if (!list_empty(&zspage->list) && !is_zspage_isolated(zspage)) {
+ get_zspage_mapping(zspage, &class_idx, &fullness);
+ remove_zspage(class, zspage, fullness);
+ }
+
+ inc_zspage_isolation(zspage);
+ spin_unlock(&class->lock);
+
+ return true;
+}
+
+int zs_page_migrate(struct address_space *mapping, struct page *newpage,
+ struct page *page, enum migrate_mode mode)
+{
+ struct zs_pool *pool;
+ struct size_class *class;
+ int class_idx;
+ enum fullness_group fullness;
+ struct zspage *zspage;
+ struct page *dummy;
+ void *s_addr, *d_addr, *addr;
+ int offset, pos;
+ unsigned long handle, head;
+ unsigned long old_obj, new_obj;
+ unsigned int obj_idx;
+ int ret = -EAGAIN;
+
+ VM_BUG_ON_PAGE(!PageMovable(page), page);
+ VM_BUG_ON_PAGE(!PageIsolated(page), page);
+
+ zspage = get_zspage(page);
+
+ /* Concurrent compactor cannot migrate any subpage in zspage */
+ migrate_write_lock(zspage);
+ get_zspage_mapping(zspage, &class_idx, &fullness);
+ pool = mapping->private_data;
+ class = pool->size_class[class_idx];
+ offset = get_first_obj_offset(page);
+
+ spin_lock(&class->lock);
+ if (!get_zspage_inuse(zspage)) {
+ ret = -EBUSY;
+ goto unlock_class;
+ }
+
+ pos = offset;
+ s_addr = kmap_atomic(page);
+ while (pos < PAGE_SIZE) {
+ head = obj_to_head(page, s_addr + pos);
+ if (head & OBJ_ALLOCATED_TAG) {
+ handle = head & ~OBJ_ALLOCATED_TAG;
+ if (!trypin_tag(handle))
+ goto unpin_objects;
+ }
+ pos += class->size;
+ }
+
+ /*
+ * Here, any user cannot access all objects in the zspage so let's move.
+ */
+ d_addr = kmap_atomic(newpage);
+ memcpy(d_addr, s_addr, PAGE_SIZE);
+ kunmap_atomic(d_addr);
+
+ for (addr = s_addr + offset; addr < s_addr + pos;
+ addr += class->size) {
+ head = obj_to_head(page, addr);
+ if (head & OBJ_ALLOCATED_TAG) {
+ handle = head & ~OBJ_ALLOCATED_TAG;
+ if (!testpin_tag(handle))
+ BUG();
+
+ old_obj = handle_to_obj(handle);
+ obj_to_location(old_obj, &dummy, &obj_idx);
+ new_obj = (unsigned long)location_to_obj(newpage,
+ obj_idx);
+ new_obj |= BIT(HANDLE_PIN_BIT);
+ record_obj(handle, new_obj);
+ }
+ }
+
+ replace_sub_page(class, zspage, newpage, page);
+ get_page(newpage);
+
+ dec_zspage_isolation(zspage);
+
+ /*
+ * Page migration is done so let's putback isolated zspage to
+ * the list if @page is final isolated subpage in the zspage.
+ */
+ if (!is_zspage_isolated(zspage))
+ putback_zspage(class, zspage);
+
+ reset_page(page);
+ put_page(page);
+ page = newpage;
+
+ ret = MIGRATEPAGE_SUCCESS;
+unpin_objects:
+ for (addr = s_addr + offset; addr < s_addr + pos;
+ addr += class->size) {
+ head = obj_to_head(page, addr);
+ if (head & OBJ_ALLOCATED_TAG) {
+ handle = head & ~OBJ_ALLOCATED_TAG;
+ if (!testpin_tag(handle))
+ BUG();
+ unpin_tag(handle);
+ }
+ }
+ kunmap_atomic(s_addr);
+unlock_class:
+ spin_unlock(&class->lock);
+ migrate_write_unlock(zspage);
+
+ return ret;
}
-static struct page *isolate_source_page(struct size_class *class)
+void zs_page_putback(struct page *page)
+{
+ struct zs_pool *pool;
+ struct size_class *class;
+ int class_idx;
+ enum fullness_group fg;
+ struct address_space *mapping;
+ struct zspage *zspage;
+
+ VM_BUG_ON_PAGE(!PageMovable(page), page);
+ VM_BUG_ON_PAGE(!PageIsolated(page), page);
+
+ zspage = get_zspage(page);
+ get_zspage_mapping(zspage, &class_idx, &fg);
+ mapping = page_mapping(page);
+ pool = mapping->private_data;
+ class = pool->size_class[class_idx];
+
+ spin_lock(&class->lock);
+ dec_zspage_isolation(zspage);
+ if (!is_zspage_isolated(zspage)) {
+ fg = putback_zspage(class, zspage);
+ /*
+ * Due to page_lock, we cannot free zspage immediately
+ * so let's defer.
+ */
+ if (fg == ZS_EMPTY)
+ schedule_work(&pool->free_work);
+ }
+ spin_unlock(&class->lock);
+}
+
+const struct address_space_operations zsmalloc_aops = {
+ .isolate_page = zs_page_isolate,
+ .migratepage = zs_page_migrate,
+ .putback_page = zs_page_putback,
+};
+
+static int zs_register_migration(struct zs_pool *pool)
+{
+ pool->inode = alloc_anon_inode(zsmalloc_mnt->mnt_sb);
+ if (IS_ERR(pool->inode)) {
+ pool->inode = NULL;
+ return 1;
+ }
+
+ pool->inode->i_mapping->private_data = pool;
+ pool->inode->i_mapping->a_ops = &zsmalloc_aops;
+ return 0;
+}
+
+static void zs_unregister_migration(struct zs_pool *pool)
+{
+ flush_work(&pool->free_work);
+ iput(pool->inode);
+}
+
+/*
+ * Caller should hold page_lock of all pages in the zspage
+ * In here, we cannot use zspage meta data.
+ */
+static void async_free_zspage(struct work_struct *work)
{
int i;
- struct page *page = NULL;
+ struct size_class *class;
+ unsigned int class_idx;
+ enum fullness_group fullness;
+ struct zspage *zspage, *tmp;
+ LIST_HEAD(free_pages);
+ struct zs_pool *pool = container_of(work, struct zs_pool,
+ free_work);
- for (i = ZS_ALMOST_EMPTY; i >= ZS_ALMOST_FULL; i--) {
- page = class->fullness_list[i];
- if (!page)
+ for (i = 0; i < zs_size_classes; i++) {
+ class = pool->size_class[i];
+ if (class->index != i)
continue;
- remove_zspage(class, i, page);
- break;
+ spin_lock(&class->lock);
+ list_splice_init(&class->fullness_list[ZS_EMPTY], &free_pages);
+ spin_unlock(&class->lock);
+ }
+
+
+ list_for_each_entry_safe(zspage, tmp, &free_pages, list) {
+ list_del(&zspage->list);
+ lock_zspage(zspage);
+
+ get_zspage_mapping(zspage, &class_idx, &fullness);
+ VM_BUG_ON(fullness != ZS_EMPTY);
+ class = pool->size_class[class_idx];
+ spin_lock(&class->lock);
+ __free_zspage(pool, pool->size_class[class_idx], zspage);
+ spin_unlock(&class->lock);
}
+};
+
+static void kick_deferred_free(struct zs_pool *pool)
+{
+ schedule_work(&pool->free_work);
+}
+
+static void init_deferred_free(struct zs_pool *pool)
+{
+ INIT_WORK(&pool->free_work, async_free_zspage);
+}
+
+static void SetZsPageMovable(struct zs_pool *pool, struct zspage *zspage)
+{
+ struct page *page = get_first_page(zspage);
- return page;
+ do {
+ WARN_ON(!trylock_page(page));
+ __SetPageMovable(page, pool->inode->i_mapping);
+ unlock_page(page);
+ } while ((page = get_next_page(page)) != NULL);
}
+#endif
/*
*
return 0;
obj_wasted = obj_allocated - obj_used;
- obj_wasted /= get_maxobj_per_zspage(class->size,
- class->pages_per_zspage);
+ obj_wasted /= class->objs_per_zspage;
return obj_wasted * class->pages_per_zspage;
}
static void __zs_compact(struct zs_pool *pool, struct size_class *class)
{
struct zs_compact_control cc;
- struct page *src_page;
- struct page *dst_page = NULL;
+ struct zspage *src_zspage;
+ struct zspage *dst_zspage = NULL;
spin_lock(&class->lock);
- while ((src_page = isolate_source_page(class))) {
+ while ((src_zspage = isolate_zspage(class, true))) {
if (!zs_can_compact(class))
break;
- cc.index = 0;
- cc.s_page = src_page;
+ cc.obj_idx = 0;
+ cc.s_page = get_first_page(src_zspage);
- while ((dst_page = isolate_target_page(class))) {
- cc.d_page = dst_page;
+ while ((dst_zspage = isolate_zspage(class, false))) {
+ cc.d_page = get_first_page(dst_zspage);
/*
* If there is no more space in dst_page, resched
* and see if anyone had allocated another zspage.
if (!migrate_zspage(pool, class, &cc))
break;
- putback_zspage(pool, class, dst_page);
+ putback_zspage(class, dst_zspage);
}
/* Stop if we couldn't find slot */
- if (dst_page == NULL)
+ if (dst_zspage == NULL)
break;
- putback_zspage(pool, class, dst_page);
- if (putback_zspage(pool, class, src_page) == ZS_EMPTY)
+ putback_zspage(class, dst_zspage);
+ if (putback_zspage(class, src_zspage) == ZS_EMPTY) {
+ free_zspage(pool, class, src_zspage);
pool->stats.pages_compacted += class->pages_per_zspage;
+ }
spin_unlock(&class->lock);
cond_resched();
spin_lock(&class->lock);
}
- if (src_page)
- putback_zspage(pool, class, src_page);
+ if (src_zspage)
+ putback_zspage(class, src_zspage);
spin_unlock(&class->lock);
}
/**
* zs_create_pool - Creates an allocation pool to work from.
- * @flags: allocation flags used to allocate pool metadata
+ * @name: pool name to be created
*
* This function must be called before anything when using
* the zsmalloc allocator.
if (!pool)
return NULL;
+ init_deferred_free(pool);
pool->size_class = kcalloc(zs_size_classes, sizeof(struct size_class *),
GFP_KERNEL);
if (!pool->size_class) {
if (!pool->name)
goto err;
- if (create_handle_cache(pool))
+ if (create_cache(pool))
goto err;
/*
for (i = zs_size_classes - 1; i >= 0; i--) {
int size;
int pages_per_zspage;
+ int objs_per_zspage;
struct size_class *class;
+ int fullness = 0;
size = ZS_MIN_ALLOC_SIZE + i * ZS_SIZE_CLASS_DELTA;
if (size > ZS_MAX_ALLOC_SIZE)
size = ZS_MAX_ALLOC_SIZE;
pages_per_zspage = get_pages_per_zspage(size);
+ objs_per_zspage = pages_per_zspage * PAGE_SIZE / size;
/*
* size_class is used for normal zsmalloc operation such
* previous size_class if possible.
*/
if (prev_class) {
- if (can_merge(prev_class, size, pages_per_zspage)) {
+ if (can_merge(prev_class, pages_per_zspage, objs_per_zspage)) {
pool->size_class[i] = prev_class;
continue;
}
class->size = size;
class->index = i;
class->pages_per_zspage = pages_per_zspage;
- class->objs_per_zspage = class->pages_per_zspage *
- PAGE_SIZE / class->size;
- if (pages_per_zspage == 1 && class->objs_per_zspage == 1)
- class->huge = true;
+ class->objs_per_zspage = objs_per_zspage;
spin_lock_init(&class->lock);
pool->size_class[i] = class;
+ for (fullness = ZS_EMPTY; fullness < NR_ZS_FULLNESS;
+ fullness++)
+ INIT_LIST_HEAD(&class->fullness_list[fullness]);
prev_class = class;
}
/* debug only, don't abort if it fails */
zs_pool_stat_create(pool, name);
+ if (zs_register_migration(pool))
+ goto err;
+
/*
* Not critical, we still can use the pool
* and user can trigger compaction manually.
int i;
zs_unregister_shrinker(pool);
+ zs_unregister_migration(pool);
zs_pool_stat_destroy(pool);
for (i = 0; i < zs_size_classes; i++) {
if (class->index != i)
continue;
- for (fg = 0; fg < _ZS_NR_FULLNESS_GROUPS; fg++) {
- if (class->fullness_list[fg]) {
+ for (fg = ZS_EMPTY; fg < NR_ZS_FULLNESS; fg++) {
+ if (!list_empty(&class->fullness_list[fg])) {
pr_info("Freeing non-empty class with size %db, fullness group %d\n",
class->size, fg);
}
kfree(class);
}
- destroy_handle_cache(pool);
+ destroy_cache(pool);
kfree(pool->size_class);
kfree(pool->name);
kfree(pool);
static int __init zs_init(void)
{
- int ret = zs_register_cpu_notifier();
+ int ret;
+
+ ret = zsmalloc_mount();
+ if (ret)
+ goto out;
+
+ ret = zs_register_cpu_notifier();
if (ret)
goto notifier_fail;
notifier_fail:
zs_unregister_cpu_notifier();
-
+ zsmalloc_unmount();
+out:
return ret;
}
#ifdef CONFIG_ZPOOL
zpool_unregister_driver(&zs_zpool_driver);
#endif
+ zsmalloc_unmount();
zs_unregister_cpu_notifier();
zs_stat_exit();
projects / cascardo / linux.git / blobdiff