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Diffstat (limited to 'drivers/staging/zcache/tmem.h')
-rw-r--r-- | drivers/staging/zcache/tmem.h | 259 |
1 files changed, 259 insertions, 0 deletions
diff --git a/drivers/staging/zcache/tmem.h b/drivers/staging/zcache/tmem.h new file mode 100644 index 0000000..adbe5a8 --- /dev/null +++ b/drivers/staging/zcache/tmem.h @@ -0,0 +1,259 @@ +/* + * tmem.h + * + * Transcendent memory + * + * Copyright (c) 2009-2012, Dan Magenheimer, Oracle Corp. + */ + +#ifndef _TMEM_H_ +#define _TMEM_H_ + +#include <linux/types.h> +#include <linux/highmem.h> +#include <linux/hash.h> +#include <linux/atomic.h> + +/* + * These are defined by the Xen<->Linux ABI so should remain consistent + */ +#define TMEM_POOL_PERSIST 1 +#define TMEM_POOL_SHARED 2 +#define TMEM_POOL_PRECOMPRESSED 4 +#define TMEM_POOL_PAGESIZE_SHIFT 4 +#define TMEM_POOL_PAGESIZE_MASK 0xf +#define TMEM_POOL_RESERVED_BITS 0x00ffff00 + +/* + * sentinels have proven very useful for debugging but can be removed + * or disabled before final merge. + */ +#undef SENTINELS +#ifdef SENTINELS +#define DECL_SENTINEL uint32_t sentinel; +#define SET_SENTINEL(_x, _y) (_x->sentinel = _y##_SENTINEL) +#define INVERT_SENTINEL(_x, _y) (_x->sentinel = ~_y##_SENTINEL) +#define ASSERT_SENTINEL(_x, _y) WARN_ON(_x->sentinel != _y##_SENTINEL) +#define ASSERT_INVERTED_SENTINEL(_x, _y) WARN_ON(_x->sentinel != ~_y##_SENTINEL) +#else +#define DECL_SENTINEL +#define SET_SENTINEL(_x, _y) do { } while (0) +#define INVERT_SENTINEL(_x, _y) do { } while (0) +#define ASSERT_SENTINEL(_x, _y) do { } while (0) +#define ASSERT_INVERTED_SENTINEL(_x, _y) do { } while (0) +#endif + +#define ASSERT_SPINLOCK(_l) lockdep_assert_held(_l) + +/* + * A pool is the highest-level data structure managed by tmem and + * usually corresponds to a large independent set of pages such as + * a filesystem. Each pool has an id, and certain attributes and counters. + * It also contains a set of hash buckets, each of which contains an rbtree + * of objects and a lock to manage concurrency within the pool. + */ + +#define TMEM_HASH_BUCKET_BITS 8 +#define TMEM_HASH_BUCKETS (1<<TMEM_HASH_BUCKET_BITS) + +struct tmem_hashbucket { + struct rb_root obj_rb_root; + spinlock_t lock; +}; + +struct tmem_pool { + void *client; /* "up" for some clients, avoids table lookup */ + struct list_head pool_list; + uint32_t pool_id; + bool persistent; + bool shared; + atomic_t obj_count; + atomic_t refcount; + struct tmem_hashbucket hashbucket[TMEM_HASH_BUCKETS]; + DECL_SENTINEL +}; + +#define is_persistent(_p) (_p->persistent) +#define is_ephemeral(_p) (!(_p->persistent)) + +/* + * An object id ("oid") is large: 192-bits (to ensure, for example, files + * in a modern filesystem can be uniquely identified). + */ + +struct tmem_oid { + uint64_t oid[3]; +}; + +static inline void tmem_oid_set_invalid(struct tmem_oid *oidp) +{ + oidp->oid[0] = oidp->oid[1] = oidp->oid[2] = -1UL; +} + +static inline bool tmem_oid_valid(struct tmem_oid *oidp) +{ + return oidp->oid[0] != -1UL || oidp->oid[1] != -1UL || + oidp->oid[2] != -1UL; +} + +static inline int tmem_oid_compare(struct tmem_oid *left, + struct tmem_oid *right) +{ + int ret; + + if (left->oid[2] == right->oid[2]) { + if (left->oid[1] == right->oid[1]) { + if (left->oid[0] == right->oid[0]) + ret = 0; + else if (left->oid[0] < right->oid[0]) + ret = -1; + else + return 1; + } else if (left->oid[1] < right->oid[1]) + ret = -1; + else + ret = 1; + } else if (left->oid[2] < right->oid[2]) + ret = -1; + else + ret = 1; + return ret; +} + +static inline unsigned tmem_oid_hash(struct tmem_oid *oidp) +{ + return hash_long(oidp->oid[0] ^ oidp->oid[1] ^ oidp->oid[2], + TMEM_HASH_BUCKET_BITS); +} + +#ifdef CONFIG_RAMSTER +struct tmem_xhandle { + uint8_t client_id; + uint8_t xh_data_cksum; + uint16_t xh_data_size; + uint16_t pool_id; + struct tmem_oid oid; + uint32_t index; + void *extra; +}; + +static inline struct tmem_xhandle tmem_xhandle_fill(uint16_t client_id, + struct tmem_pool *pool, + struct tmem_oid *oidp, + uint32_t index) +{ + struct tmem_xhandle xh; + xh.client_id = client_id; + xh.xh_data_cksum = (uint8_t)-1; + xh.xh_data_size = (uint16_t)-1; + xh.pool_id = pool->pool_id; + xh.oid = *oidp; + xh.index = index; + return xh; +} +#endif + + +/* + * A tmem_obj contains an identifier (oid), pointers to the parent + * pool and the rb_tree to which it belongs, counters, and an ordered + * set of pampds, structured in a radix-tree-like tree. The intermediate + * nodes of the tree are called tmem_objnodes. + */ + +struct tmem_objnode; + +struct tmem_obj { + struct tmem_oid oid; + struct tmem_pool *pool; + struct rb_node rb_tree_node; + struct tmem_objnode *objnode_tree_root; + unsigned int objnode_tree_height; + unsigned long objnode_count; + long pampd_count; +#ifdef CONFIG_RAMSTER + /* + * for current design of ramster, all pages belonging to + * an object reside on the same remotenode and extra is + * used to record the number of the remotenode so a + * flush-object operation can specify it + */ + void *extra; /* for private use by pampd implementation */ +#endif + DECL_SENTINEL +}; + +#define OBJNODE_TREE_MAP_SHIFT 6 +#define OBJNODE_TREE_MAP_SIZE (1UL << OBJNODE_TREE_MAP_SHIFT) +#define OBJNODE_TREE_MAP_MASK (OBJNODE_TREE_MAP_SIZE-1) +#define OBJNODE_TREE_INDEX_BITS (8 /* CHAR_BIT */ * sizeof(unsigned long)) +#define OBJNODE_TREE_MAX_PATH \ + (OBJNODE_TREE_INDEX_BITS/OBJNODE_TREE_MAP_SHIFT + 2) + +struct tmem_objnode { + struct tmem_obj *obj; + DECL_SENTINEL + void *slots[OBJNODE_TREE_MAP_SIZE]; + unsigned int slots_in_use; +}; + +struct tmem_handle { + struct tmem_oid oid; /* 24 bytes */ + uint32_t index; + uint16_t pool_id; + uint16_t client_id; +}; + + +/* pampd abstract datatype methods provided by the PAM implementation */ +struct tmem_pamops { + void (*create_finish)(void *, bool); + int (*get_data)(char *, size_t *, bool, void *, struct tmem_pool *, + struct tmem_oid *, uint32_t); + int (*get_data_and_free)(char *, size_t *, bool, void *, + struct tmem_pool *, struct tmem_oid *, + uint32_t); + void (*free)(void *, struct tmem_pool *, + struct tmem_oid *, uint32_t, bool); +#ifdef CONFIG_RAMSTER + void (*new_obj)(struct tmem_obj *); + void (*free_obj)(struct tmem_pool *, struct tmem_obj *, bool); + void *(*repatriate_preload)(void *, struct tmem_pool *, + struct tmem_oid *, uint32_t, bool *); + int (*repatriate)(void *, void *, struct tmem_pool *, + struct tmem_oid *, uint32_t, bool, void *); + bool (*is_remote)(void *); + int (*replace_in_obj)(void *, struct tmem_obj *); +#endif +}; +extern void tmem_register_pamops(struct tmem_pamops *m); + +/* memory allocation methods provided by the host implementation */ +struct tmem_hostops { + struct tmem_obj *(*obj_alloc)(struct tmem_pool *); + void (*obj_free)(struct tmem_obj *, struct tmem_pool *); + struct tmem_objnode *(*objnode_alloc)(struct tmem_pool *); + void (*objnode_free)(struct tmem_objnode *, struct tmem_pool *); +}; +extern void tmem_register_hostops(struct tmem_hostops *m); + +/* core tmem accessor functions */ +extern int tmem_put(struct tmem_pool *, struct tmem_oid *, uint32_t index, + bool, void *); +extern int tmem_get(struct tmem_pool *, struct tmem_oid *, uint32_t index, + char *, size_t *, bool, int); +extern int tmem_flush_page(struct tmem_pool *, struct tmem_oid *, + uint32_t index); +extern int tmem_flush_object(struct tmem_pool *, struct tmem_oid *); +extern int tmem_destroy_pool(struct tmem_pool *); +extern void tmem_new_pool(struct tmem_pool *, uint32_t); +#ifdef CONFIG_RAMSTER +extern int tmem_replace(struct tmem_pool *, struct tmem_oid *, uint32_t index, + void *); +extern void *tmem_localify_get_pampd(struct tmem_pool *, struct tmem_oid *, + uint32_t index, struct tmem_obj **, + void **); +extern void tmem_localify_finish(struct tmem_obj *, uint32_t index, + void *, void *, bool); +#endif +#endif /* _TMEM_H */ |