* Structures
*****************/
struct z3fold_pool;
-struct z3fold_ops {
- int (*evict)(struct z3fold_pool *pool, unsigned long handle);
-};
enum buddy {
HEADLESS = 0,
/**
* struct z3fold_pool - stores metadata for each z3fold pool
* @name: pool name
- * @lock: protects pool unbuddied/lru lists
+ * @lock: protects pool unbuddied lists
* @stale_lock: protects pool stale page list
* @unbuddied: per-cpu array of lists tracking z3fold pages that contain 2-
* buddies; the list each z3fold page is added to depends on
* the size of its free region.
- * @lru: list tracking the z3fold pages in LRU order by most recently
- * added buddy.
* @stale: list of pages marked for freeing
* @pages_nr: number of z3fold pages in the pool.
* @c_handle: cache for z3fold_buddy_slots allocation
- * @ops: pointer to a structure of user defined operations specified at
- * pool creation time.
- * @zpool: zpool driver
- * @zpool_ops: zpool operations structure with an evict callback
* @compact_wq: workqueue for page layout background optimization
* @release_wq: workqueue for safe page release
* @work: work_struct for safe page release
spinlock_t lock;
spinlock_t stale_lock;
struct list_head *unbuddied;
- struct list_head lru;
struct list_head stale;
atomic64_t pages_nr;
struct kmem_cache *c_handle;
- const struct z3fold_ops *ops;
- struct zpool *zpool;
- const struct zpool_ops *zpool_ops;
struct workqueue_struct *compact_wq;
struct workqueue_struct *release_wq;
struct work_struct work;
struct z3fold_header *zhdr = page_address(page);
struct z3fold_buddy_slots *slots;
- INIT_LIST_HEAD(&page->lru);
clear_bit(PAGE_HEADLESS, &page->private);
clear_bit(MIDDLE_CHUNK_MAPPED, &page->private);
clear_bit(NEEDS_COMPACTING, &page->private);
}
/*
- * Encodes the handle of a particular buddy within a z3fold page
- * Pool lock should be held as this function accesses first_num
+ * Encodes the handle of a particular buddy within a z3fold page.
+ * Zhdr->page_lock should be held as this function accesses first_num
+ * if bud != HEADLESS.
*/
static unsigned long __encode_handle(struct z3fold_header *zhdr,
struct z3fold_buddy_slots *slots,
set_bit(PAGE_STALE, &page->private);
clear_bit(NEEDS_COMPACTING, &page->private);
spin_lock(&pool->lock);
- if (!list_empty(&page->lru))
- list_del_init(&page->lru);
spin_unlock(&pool->lock);
if (locked)
__release_z3fold_page(zhdr, true);
}
+static inline int put_z3fold_locked(struct z3fold_header *zhdr)
+{
+ return kref_put(&zhdr->refcount, release_z3fold_page_locked);
+}
+
+static inline int put_z3fold_locked_list(struct z3fold_header *zhdr)
+{
+ return kref_put(&zhdr->refcount, release_z3fold_page_locked_list);
+}
+
static void free_pages_work(struct work_struct *w)
{
struct z3fold_pool *pool = container_of(w, struct z3fold_pool, work);
return new_zhdr;
out_fail:
- if (new_zhdr && !kref_put(&new_zhdr->refcount, release_z3fold_page_locked)) {
+ if (new_zhdr && !put_z3fold_locked(new_zhdr)) {
add_to_unbuddied(pool, new_zhdr);
z3fold_page_unlock(new_zhdr);
}
list_del_init(&zhdr->buddy);
spin_unlock(&pool->lock);
- if (kref_put(&zhdr->refcount, release_z3fold_page_locked))
+ if (put_z3fold_locked(zhdr))
return;
if (test_bit(PAGE_STALE, &page->private) ||
if (!zhdr->foreign_handles && buddy_single(zhdr) &&
zhdr->mapped_count == 0 && compact_single_buddy(zhdr)) {
- if (!kref_put(&zhdr->refcount, release_z3fold_page_locked)) {
+ if (!put_z3fold_locked(zhdr)) {
clear_bit(PAGE_CLAIMED, &page->private);
z3fold_page_unlock(zhdr);
}
return zhdr;
out_fail:
- if (!kref_put(&zhdr->refcount, release_z3fold_page_locked)) {
+ if (!put_z3fold_locked(zhdr)) {
add_to_unbuddied(pool, zhdr);
z3fold_page_unlock(zhdr);
}
* z3fold_create_pool() - create a new z3fold pool
* @name: pool name
* @gfp: gfp flags when allocating the z3fold pool structure
- * @ops: user-defined operations for the z3fold pool
*
* Return: pointer to the new z3fold pool or NULL if the metadata allocation
* failed.
*/
-static struct z3fold_pool *z3fold_create_pool(const char *name, gfp_t gfp,
- const struct z3fold_ops *ops)
+static struct z3fold_pool *z3fold_create_pool(const char *name, gfp_t gfp)
{
struct z3fold_pool *pool = NULL;
int i, cpu;
for_each_unbuddied_list(i, 0)
INIT_LIST_HEAD(&unbuddied[i]);
}
- INIT_LIST_HEAD(&pool->lru);
INIT_LIST_HEAD(&pool->stale);
atomic64_set(&pool->pages_nr, 0);
pool->name = name;
if (!pool->release_wq)
goto out_wq;
INIT_WORK(&pool->work, free_pages_work);
- pool->ops = ops;
return pool;
out_wq:
if (zhdr) {
bud = get_free_buddy(zhdr, chunks);
if (bud == HEADLESS) {
- if (!kref_put(&zhdr->refcount,
- release_z3fold_page_locked))
+ if (!put_z3fold_locked(zhdr))
z3fold_page_unlock(zhdr);
pr_err("No free chunks in unbuddied\n");
WARN_ON(1);
headless:
spin_lock(&pool->lock);
- /* Add/move z3fold page to beginning of LRU */
- if (!list_empty(&page->lru))
- list_del(&page->lru);
-
- list_add(&page->lru, &pool->lru);
-
*handle = encode_handle(zhdr, bud);
spin_unlock(&pool->lock);
if (bud != HEADLESS)
* immediately so we don't care about its value any more.
*/
if (!page_claimed) {
- spin_lock(&pool->lock);
- list_del(&page->lru);
- spin_unlock(&pool->lock);
put_z3fold_header(zhdr);
free_z3fold_page(page, true);
atomic64_dec(&pool->pages_nr);
if (!page_claimed)
free_handle(handle, zhdr);
- if (kref_put(&zhdr->refcount, release_z3fold_page_locked_list))
+ if (put_z3fold_locked_list(zhdr))
return;
if (page_claimed) {
/* the page has not been claimed by us */
put_z3fold_header(zhdr);
}
-/**
- * z3fold_reclaim_page() - evicts allocations from a pool page and frees it
- * @pool: pool from which a page will attempt to be evicted
- * @retries: number of pages on the LRU list for which eviction will
- * be attempted before failing
- *
- * z3fold reclaim is different from normal system reclaim in that it is done
- * from the bottom, up. This is because only the bottom layer, z3fold, has
- * information on how the allocations are organized within each z3fold page.
- * This has the potential to create interesting locking situations between
- * z3fold and the user, however.
- *
- * To avoid these, this is how z3fold_reclaim_page() should be called:
- *
- * The user detects a page should be reclaimed and calls z3fold_reclaim_page().
- * z3fold_reclaim_page() will remove a z3fold page from the pool LRU list and
- * call the user-defined eviction handler with the pool and handle as
- * arguments.
- *
- * If the handle can not be evicted, the eviction handler should return
- * non-zero. z3fold_reclaim_page() will add the z3fold page back to the
- * appropriate list and try the next z3fold page on the LRU up to
- * a user defined number of retries.
- *
- * If the handle is successfully evicted, the eviction handler should
- * return 0 _and_ should have called z3fold_free() on the handle. z3fold_free()
- * contains logic to delay freeing the page if the page is under reclaim,
- * as indicated by the setting of the PG_reclaim flag on the underlying page.
- *
- * If all buddies in the z3fold page are successfully evicted, then the
- * z3fold page can be freed.
- *
- * Returns: 0 if page is successfully freed, otherwise -EINVAL if there are
- * no pages to evict or an eviction handler is not registered, -EAGAIN if
- * the retry limit was hit.
- */
-static int z3fold_reclaim_page(struct z3fold_pool *pool, unsigned int retries)
-{
- int i, ret = -1;
- struct z3fold_header *zhdr = NULL;
- struct page *page = NULL;
- struct list_head *pos;
- unsigned long first_handle = 0, middle_handle = 0, last_handle = 0;
- struct z3fold_buddy_slots slots __attribute__((aligned(SLOTS_ALIGN)));
-
- rwlock_init(&slots.lock);
- slots.pool = (unsigned long)pool | (1 << HANDLES_NOFREE);
-
- spin_lock(&pool->lock);
- if (!pool->ops || !pool->ops->evict || retries == 0) {
- spin_unlock(&pool->lock);
- return -EINVAL;
- }
- for (i = 0; i < retries; i++) {
- if (list_empty(&pool->lru)) {
- spin_unlock(&pool->lock);
- return -EINVAL;
- }
- list_for_each_prev(pos, &pool->lru) {
- page = list_entry(pos, struct page, lru);
-
- zhdr = page_address(page);
- if (test_bit(PAGE_HEADLESS, &page->private)) {
- /*
- * For non-headless pages, we wait to do this
- * until we have the page lock to avoid racing
- * with __z3fold_alloc(). Headless pages don't
- * have a lock (and __z3fold_alloc() will never
- * see them), but we still need to test and set
- * PAGE_CLAIMED to avoid racing with
- * z3fold_free(), so just do it now before
- * leaving the loop.
- */
- if (test_and_set_bit(PAGE_CLAIMED, &page->private))
- continue;
-
- break;
- }
-
- if (!z3fold_page_trylock(zhdr)) {
- zhdr = NULL;
- continue; /* can't evict at this point */
- }
-
- /* test_and_set_bit is of course atomic, but we still
- * need to do it under page lock, otherwise checking
- * that bit in __z3fold_alloc wouldn't make sense
- */
- if (zhdr->foreign_handles ||
- test_and_set_bit(PAGE_CLAIMED, &page->private)) {
- z3fold_page_unlock(zhdr);
- zhdr = NULL;
- continue; /* can't evict such page */
- }
- list_del_init(&zhdr->buddy);
- zhdr->cpu = -1;
- /* See comment in __z3fold_alloc. */
- kref_get(&zhdr->refcount);
- break;
- }
-
- if (!zhdr)
- break;
-
- list_del_init(&page->lru);
- spin_unlock(&pool->lock);
-
- if (!test_bit(PAGE_HEADLESS, &page->private)) {
- /*
- * We need encode the handles before unlocking, and
- * use our local slots structure because z3fold_free
- * can zero out zhdr->slots and we can't do much
- * about that
- */
- first_handle = 0;
- last_handle = 0;
- middle_handle = 0;
- memset(slots.slot, 0, sizeof(slots.slot));
- if (zhdr->first_chunks)
- first_handle = __encode_handle(zhdr, &slots,
- FIRST);
- if (zhdr->middle_chunks)
- middle_handle = __encode_handle(zhdr, &slots,
- MIDDLE);
- if (zhdr->last_chunks)
- last_handle = __encode_handle(zhdr, &slots,
- LAST);
- /*
- * it's safe to unlock here because we hold a
- * reference to this page
- */
- z3fold_page_unlock(zhdr);
- } else {
- first_handle = encode_handle(zhdr, HEADLESS);
- last_handle = middle_handle = 0;
- }
- /* Issue the eviction callback(s) */
- if (middle_handle) {
- ret = pool->ops->evict(pool, middle_handle);
- if (ret)
- goto next;
- }
- if (first_handle) {
- ret = pool->ops->evict(pool, first_handle);
- if (ret)
- goto next;
- }
- if (last_handle) {
- ret = pool->ops->evict(pool, last_handle);
- if (ret)
- goto next;
- }
-next:
- if (test_bit(PAGE_HEADLESS, &page->private)) {
- if (ret == 0) {
- free_z3fold_page(page, true);
- atomic64_dec(&pool->pages_nr);
- return 0;
- }
- spin_lock(&pool->lock);
- list_add(&page->lru, &pool->lru);
- spin_unlock(&pool->lock);
- clear_bit(PAGE_CLAIMED, &page->private);
- } else {
- struct z3fold_buddy_slots *slots = zhdr->slots;
- z3fold_page_lock(zhdr);
- if (kref_put(&zhdr->refcount,
- release_z3fold_page_locked)) {
- kmem_cache_free(pool->c_handle, slots);
- return 0;
- }
- /*
- * if we are here, the page is still not completely
- * free. Take the global pool lock then to be able
- * to add it back to the lru list
- */
- spin_lock(&pool->lock);
- list_add(&page->lru, &pool->lru);
- spin_unlock(&pool->lock);
- if (list_empty(&zhdr->buddy))
- add_to_unbuddied(pool, zhdr);
- clear_bit(PAGE_CLAIMED, &page->private);
- z3fold_page_unlock(zhdr);
- }
-
- /* We started off locked to we need to lock the pool back */
- spin_lock(&pool->lock);
- }
- spin_unlock(&pool->lock);
- return -EAGAIN;
-}
-
/**
* z3fold_map() - maps the allocation associated with the given handle
* @pool: pool in which the allocation resides
struct z3fold_header *zhdr;
struct z3fold_pool *pool;
- VM_BUG_ON_PAGE(!PageMovable(page), page);
VM_BUG_ON_PAGE(PageIsolated(page), page);
if (test_bit(PAGE_HEADLESS, &page->private))
spin_lock(&pool->lock);
if (!list_empty(&zhdr->buddy))
list_del_init(&zhdr->buddy);
- if (!list_empty(&page->lru))
- list_del_init(&page->lru);
spin_unlock(&pool->lock);
kref_get(&zhdr->refcount);
struct z3fold_header *zhdr, *new_zhdr;
struct z3fold_pool *pool;
- VM_BUG_ON_PAGE(!PageMovable(page), page);
VM_BUG_ON_PAGE(!PageIsolated(page), page);
VM_BUG_ON_PAGE(!test_bit(PAGE_CLAIMED, &page->private), page);
VM_BUG_ON_PAGE(!PageLocked(newpage), newpage);
encode_handle(new_zhdr, MIDDLE);
set_bit(NEEDS_COMPACTING, &newpage->private);
new_zhdr->cpu = smp_processor_id();
- spin_lock(&pool->lock);
- list_add(&newpage->lru, &pool->lru);
- spin_unlock(&pool->lock);
__SetPageMovable(newpage, &z3fold_mops);
z3fold_page_unlock(new_zhdr);
if (!list_empty(&zhdr->buddy))
list_del_init(&zhdr->buddy);
INIT_LIST_HEAD(&page->lru);
- if (kref_put(&zhdr->refcount, release_z3fold_page_locked))
+ if (put_z3fold_locked(zhdr))
return;
- spin_lock(&pool->lock);
- list_add(&page->lru, &pool->lru);
- spin_unlock(&pool->lock);
if (list_empty(&zhdr->buddy))
add_to_unbuddied(pool, zhdr);
clear_bit(PAGE_CLAIMED, &page->private);
* zpool
****************/
-static int z3fold_zpool_evict(struct z3fold_pool *pool, unsigned long handle)
+static void *z3fold_zpool_create(const char *name, gfp_t gfp)
{
- if (pool->zpool && pool->zpool_ops && pool->zpool_ops->evict)
- return pool->zpool_ops->evict(pool->zpool, handle);
- else
- return -ENOENT;
-}
-
-static const struct z3fold_ops z3fold_zpool_ops = {
- .evict = z3fold_zpool_evict
-};
-
-static void *z3fold_zpool_create(const char *name, gfp_t gfp,
- const struct zpool_ops *zpool_ops,
- struct zpool *zpool)
-{
- struct z3fold_pool *pool;
-
- pool = z3fold_create_pool(name, gfp,
- zpool_ops ? &z3fold_zpool_ops : NULL);
- if (pool) {
- pool->zpool = zpool;
- pool->zpool_ops = zpool_ops;
- }
- return pool;
+ return z3fold_create_pool(name, gfp);
}
static void z3fold_zpool_destroy(void *pool)
z3fold_free(pool, handle);
}
-static int z3fold_zpool_shrink(void *pool, unsigned int pages,
- unsigned int *reclaimed)
-{
- unsigned int total = 0;
- int ret = -EINVAL;
-
- while (total < pages) {
- ret = z3fold_reclaim_page(pool, 8);
- if (ret < 0)
- break;
- total++;
- }
-
- if (reclaimed)
- *reclaimed = total;
-
- return ret;
-}
-
static void *z3fold_zpool_map(void *pool, unsigned long handle,
enum zpool_mapmode mm)
{
.destroy = z3fold_zpool_destroy,
.malloc = z3fold_zpool_malloc,
.free = z3fold_zpool_free,
- .shrink = z3fold_zpool_shrink,
.map = z3fold_zpool_map,
.unmap = z3fold_zpool_unmap,
.total_size = z3fold_zpool_total_size,
projects / linux-2.6-microblaze.git / blobdiff