[mirror_ubuntu-artful-kernel.git] / kernel / trace / tracing_map.h

#ifndef __TRACING_MAP_H
#define __TRACING_MAP_H

#define TRACING_MAP_BITS_DEFAULT	11
#define TRACING_MAP_BITS_MAX		17
#define TRACING_MAP_BITS_MIN		7

#define TRACING_MAP_KEYS_MAX		2
#define TRACING_MAP_VALS_MAX		3
#define TRACING_MAP_FIELDS_MAX		(TRACING_MAP_KEYS_MAX + \
					 TRACING_MAP_VALS_MAX)
#define TRACING_MAP_SORT_KEYS_MAX	2

typedef int (*tracing_map_cmp_fn_t) (void *val_a, void *val_b);

/*
 * This is an overview of the tracing_map data structures and how they
 * relate to the tracing_map API.  The details of the algorithms
 * aren't discussed here - this is just a general overview of the data
 * structures and how they interact with the API.
 *
 * The central data structure of the tracing_map is an initially
 * zeroed array of struct tracing_map_entry (stored in the map field
 * of struct tracing_map).  tracing_map_entry is a very simple data
 * structure containing only two fields: a 32-bit unsigned 'key'
 * variable and a pointer named 'val'.  This array of struct
 * tracing_map_entry is essentially a hash table which will be
 * modified by a single function, tracing_map_insert(), but which can
 * be traversed and read by a user at any time (though the user does
 * this indirectly via an array of tracing_map_sort_entry - see the
 * explanation of that data structure in the discussion of the
 * sorting-related data structures below).
 *
 * The central function of the tracing_map API is
 * tracing_map_insert().  tracing_map_insert() hashes the
 * arbitrarily-sized key passed into it into a 32-bit unsigned key.
 * It then uses this key, truncated to the array size, as an index
 * into the array of tracing_map_entries.  If the value of the 'key'
 * field of the tracing_map_entry found at that location is 0, then
 * that entry is considered to be free and can be claimed, by
 * replacing the 0 in the 'key' field of the tracing_map_entry with
 * the new 32-bit hashed key.  Once claimed, that tracing_map_entry's
 * 'val' field is then used to store a unique element which will be
 * forever associated with that 32-bit hashed key in the
 * tracing_map_entry.
 *
 * That unique element now in the tracing_map_entry's 'val' field is
 * an instance of tracing_map_elt, where 'elt' in the latter part of
 * that variable name is short for 'element'.  The purpose of a
 * tracing_map_elt is to hold values specific to the particular
 * 32-bit hashed key it's assocated with.  Things such as the unique
 * set of aggregated sums associated with the 32-bit hashed key, along
 * with a copy of the full key associated with the entry, and which
 * was used to produce the 32-bit hashed key.
 *
 * When tracing_map_create() is called to create the tracing map, the
 * user specifies (indirectly via the map_bits param, the details are
 * unimportant for this discussion) the maximum number of elements
 * that the map can hold (stored in the max_elts field of struct
 * tracing_map).  This is the maximum possible number of
 * tracing_map_entries in the tracing_map_entry array which can be
 * 'claimed' as described in the above discussion, and therefore is
 * also the maximum number of tracing_map_elts that can be associated
 * with the tracing_map_entry array in the tracing_map.  Because of
 * the way the insertion algorithm works, the size of the allocated
 * tracing_map_entry array is always twice the maximum number of
 * elements (2 * max_elts).  This value is stored in the map_size
 * field of struct tracing_map.
 *
 * Because tracing_map_insert() needs to work from any context,
 * including from within the memory allocation functions themselves,
 * both the tracing_map_entry array and a pool of max_elts
 * tracing_map_elts are pre-allocated before any call is made to
 * tracing_map_insert().
 *
 * The tracing_map_entry array is allocated as a single block by
 * tracing_map_create().
 *
 * Because the tracing_map_elts are much larger objects and can't
 * generally be allocated together as a single large array without
 * failure, they're allocated individually, by tracing_map_init().
 *
 * The pool of tracing_map_elts are allocated by tracing_map_init()
 * rather than by tracing_map_create() because at the time
 * tracing_map_create() is called, there isn't enough information to
 * create the tracing_map_elts.  Specifically,the user first needs to
 * tell the tracing_map implementation how many fields the
 * tracing_map_elts contain, and which types of fields they are (key
 * or sum).  The user does this via the tracing_map_add_sum_field()
 * and tracing_map_add_key_field() functions, following which the user
 * calls tracing_map_init() to finish up the tracing map setup.  The
 * array holding the pointers which make up the pre-allocated pool of
 * tracing_map_elts is allocated as a single block and is stored in
 * the elts field of struct tracing_map.
 *
 * There is also a set of structures used for sorting that might
 * benefit from some minimal explanation.
 *
 * struct tracing_map_sort_key is used to drive the sort at any given
 * time.  By 'any given time' we mean that a different
 * tracing_map_sort_key will be used at different times depending on
 * whether the sort currently being performed is a primary or a
 * secondary sort.
 *
 * The sort key is very simple, consisting of the field index of the
 * tracing_map_elt field to sort on (which the user saved when adding
 * the field), and whether the sort should be done in an ascending or
 * descending order.
 *
 * For the convenience of the sorting code, a tracing_map_sort_entry
 * is created for each tracing_map_elt, again individually allocated
 * to avoid failures that might be expected if allocated as a single
 * large array of struct tracing_map_sort_entry.
 * tracing_map_sort_entry instances are the objects expected by the
 * various internal sorting functions, and are also what the user
 * ultimately receives after calling tracing_map_sort_entries().
 * Because it doesn't make sense for users to access an unordered and
 * sparsely populated tracing_map directly, the
 * tracing_map_sort_entries() function is provided so that users can
 * retrieve a sorted list of all existing elements.  In addition to
 * the associated tracing_map_elt 'elt' field contained within the
 * tracing_map_sort_entry, which is the object of interest to the
 * user, tracing_map_sort_entry objects contain a number of additional
 * fields which are used for caching and internal purposes and can
 * safely be ignored.
*/

struct tracing_map_field {
	tracing_map_cmp_fn_t		cmp_fn;
	union {
		atomic64_t			sum;
		unsigned int			offset;
	};
};

struct tracing_map_elt {
	struct tracing_map		*map;
	struct tracing_map_field	*fields;
	void				*key;
	void				*private_data;
};

struct tracing_map_entry {
	u32				key;
	struct tracing_map_elt		*val;
};

struct tracing_map_sort_key {
	unsigned int			field_idx;
	bool				descending;
};

struct tracing_map_sort_entry {
	void				*key;
	struct tracing_map_elt		*elt;
	bool				elt_copied;
	bool				dup;
};

struct tracing_map_array {
	unsigned int entries_per_page;
	unsigned int entry_size_shift;
	unsigned int entry_shift;
	unsigned int entry_mask;
	unsigned int n_pages;
	void **pages;
};

#define TRACING_MAP_ARRAY_ELT(array, idx)				\
	(array->pages[idx >> array->entry_shift] +			\
	 ((idx & array->entry_mask) << array->entry_size_shift))

#define TRACING_MAP_ENTRY(array, idx)					\
	((struct tracing_map_entry *)TRACING_MAP_ARRAY_ELT(array, idx))

#define TRACING_MAP_ELT(array, idx)					\
	((struct tracing_map_elt **)TRACING_MAP_ARRAY_ELT(array, idx))

struct tracing_map {
	unsigned int			key_size;
	unsigned int			map_bits;
	unsigned int			map_size;
	unsigned int			max_elts;
	atomic_t			next_elt;
	struct tracing_map_array	*elts;
	struct tracing_map_array	*map;
	const struct tracing_map_ops	*ops;
	void				*private_data;
	struct tracing_map_field	fields[TRACING_MAP_FIELDS_MAX];
	unsigned int			n_fields;
	int				key_idx[TRACING_MAP_KEYS_MAX];
	unsigned int			n_keys;
	struct tracing_map_sort_key	sort_key;
	atomic64_t			hits;
	atomic64_t			drops;
};

/**
 * struct tracing_map_ops - callbacks for tracing_map
 *
 * The methods in this structure define callback functions for various
 * operations on a tracing_map or objects related to a tracing_map.
 *
 * For a detailed description of tracing_map_elt objects please see
 * the overview of tracing_map data structures at the beginning of
 * this file.
 *
 * All the methods below are optional.
 *
 * @elt_alloc: When a tracing_map_elt is allocated, this function, if
 *	defined, will be called and gives clients the opportunity to
 *	allocate additional data and attach it to the element
 *	(tracing_map_elt->private_data is meant for that purpose).
 *	Element allocation occurs before tracing begins, when the
 *	tracing_map_init() call is made by client code.
 *
 * @elt_copy: At certain points in the lifetime of an element, it may
 *	need to be copied.  The copy should include a copy of the
 *	client-allocated data, which can be copied into the 'to'
 *	element from the 'from' element.
 *
 * @elt_free: When a tracing_map_elt is freed, this function is called
 *	and allows client-allocated per-element data to be freed.
 *
 * @elt_clear: This callback allows per-element client-defined data to
 *	be cleared, if applicable.
 *
 * @elt_init: This callback allows per-element client-defined data to
 *	be initialized when used i.e. when the element is actually
 *	claimed by tracing_map_insert() in the context of the map
 *	insertion.
 */
struct tracing_map_ops {
	int			(*elt_alloc)(struct tracing_map_elt *elt);
	void			(*elt_copy)(struct tracing_map_elt *to,
					    struct tracing_map_elt *from);
	void			(*elt_free)(struct tracing_map_elt *elt);
	void			(*elt_clear)(struct tracing_map_elt *elt);
	void			(*elt_init)(struct tracing_map_elt *elt);
};

extern struct tracing_map *
tracing_map_create(unsigned int map_bits,
		   unsigned int key_size,
		   const struct tracing_map_ops *ops,
		   void *private_data);
extern int tracing_map_init(struct tracing_map *map);

extern int tracing_map_add_sum_field(struct tracing_map *map);
extern int tracing_map_add_key_field(struct tracing_map *map,
				     unsigned int offset,
				     tracing_map_cmp_fn_t cmp_fn);

extern void tracing_map_destroy(struct tracing_map *map);
extern void tracing_map_clear(struct tracing_map *map);

extern struct tracing_map_elt *
tracing_map_insert(struct tracing_map *map, void *key);
extern struct tracing_map_elt *
tracing_map_lookup(struct tracing_map *map, void *key);

extern tracing_map_cmp_fn_t tracing_map_cmp_num(int field_size,
						int field_is_signed);
extern int tracing_map_cmp_string(void *val_a, void *val_b);
extern int tracing_map_cmp_none(void *val_a, void *val_b);

extern void tracing_map_update_sum(struct tracing_map_elt *elt,
				   unsigned int i, u64 n);
extern u64 tracing_map_read_sum(struct tracing_map_elt *elt, unsigned int i);
extern void tracing_map_set_field_descr(struct tracing_map *map,
					unsigned int i,
					unsigned int key_offset,
					tracing_map_cmp_fn_t cmp_fn);
extern int
tracing_map_sort_entries(struct tracing_map *map,
			 struct tracing_map_sort_key *sort_keys,
			 unsigned int n_sort_keys,
			 struct tracing_map_sort_entry ***sort_entries);

extern void
tracing_map_destroy_sort_entries(struct tracing_map_sort_entry **entries,
				 unsigned int n_entries);
#endif /* __TRACING_MAP_H */
Commit	Line	Data
08d43a5f TZ	1	#ifndef __TRACING_MAP_H
	2	#define __TRACING_MAP_H
	3
	4	#define TRACING_MAP_BITS_DEFAULT 11
	5	#define TRACING_MAP_BITS_MAX 17
	6	#define TRACING_MAP_BITS_MIN 7
	7
08d43a5f	8	#define TRACING_MAP_KEYS_MAX 2
3b772b96 TZ	9	#define TRACING_MAP_VALS_MAX 3
	10	#define TRACING_MAP_FIELDS_MAX (TRACING_MAP_KEYS_MAX + \
	11	TRACING_MAP_VALS_MAX)
08d43a5f TZ	12	#define TRACING_MAP_SORT_KEYS_MAX 2
	13
	14	typedef int (tracing_map_cmp_fn_t) (void val_a, void *val_b);
	15
	16	/*
	17	* This is an overview of the tracing_map data structures and how they
	18	* relate to the tracing_map API. The details of the algorithms
	19	* aren't discussed here - this is just a general overview of the data
	20	* structures and how they interact with the API.
	21	*
	22	* The central data structure of the tracing_map is an initially
	23	* zeroed array of struct tracing_map_entry (stored in the map field
	24	* of struct tracing_map). tracing_map_entry is a very simple data
	25	* structure containing only two fields: a 32-bit unsigned 'key'
	26	* variable and a pointer named 'val'. This array of struct
	27	* tracing_map_entry is essentially a hash table which will be
	28	* modified by a single function, tracing_map_insert(), but which can
	29	* be traversed and read by a user at any time (though the user does
	30	* this indirectly via an array of tracing_map_sort_entry - see the
	31	* explanation of that data structure in the discussion of the
	32	* sorting-related data structures below).
	33	*
	34	* The central function of the tracing_map API is
	35	* tracing_map_insert(). tracing_map_insert() hashes the
	36	* arbitrarily-sized key passed into it into a 32-bit unsigned key.
	37	* It then uses this key, truncated to the array size, as an index
	38	* into the array of tracing_map_entries. If the value of the 'key'
	39	* field of the tracing_map_entry found at that location is 0, then
	40	* that entry is considered to be free and can be claimed, by
	41	* replacing the 0 in the 'key' field of the tracing_map_entry with
	42	* the new 32-bit hashed key. Once claimed, that tracing_map_entry's
	43	* 'val' field is then used to store a unique element which will be
	44	* forever associated with that 32-bit hashed key in the
	45	* tracing_map_entry.
	46	*
	47	* That unique element now in the tracing_map_entry's 'val' field is
	48	* an instance of tracing_map_elt, where 'elt' in the latter part of
	49	* that variable name is short for 'element'. The purpose of a
8d44f2f3	50	* tracing_map_elt is to hold values specific to the particular
08d43a5f TZ	51	* 32-bit hashed key it's assocated with. Things such as the unique
	52	* set of aggregated sums associated with the 32-bit hashed key, along
	53	* with a copy of the full key associated with the entry, and which
	54	* was used to produce the 32-bit hashed key.
	55	*
	56	* When tracing_map_create() is called to create the tracing map, the
	57	* user specifies (indirectly via the map_bits param, the details are
	58	* unimportant for this discussion) the maximum number of elements
	59	* that the map can hold (stored in the max_elts field of struct
	60	* tracing_map). This is the maximum possible number of
	61	* tracing_map_entries in the tracing_map_entry array which can be
	62	* 'claimed' as described in the above discussion, and therefore is
	63	* also the maximum number of tracing_map_elts that can be associated
	64	* with the tracing_map_entry array in the tracing_map. Because of
	65	* the way the insertion algorithm works, the size of the allocated
	66	* tracing_map_entry array is always twice the maximum number of
	67	* elements (2 * max_elts). This value is stored in the map_size
	68	* field of struct tracing_map.
	69	*
	70	* Because tracing_map_insert() needs to work from any context,
	71	* including from within the memory allocation functions themselves,
	72	* both the tracing_map_entry array and a pool of max_elts
	73	* tracing_map_elts are pre-allocated before any call is made to
	74	* tracing_map_insert().
	75	*
	76	* The tracing_map_entry array is allocated as a single block by
	77	* tracing_map_create().
	78	*
	79	* Because the tracing_map_elts are much larger objects and can't
	80	* generally be allocated together as a single large array without
	81	* failure, they're allocated individually, by tracing_map_init().
	82	*
	83	* The pool of tracing_map_elts are allocated by tracing_map_init()
	84	* rather than by tracing_map_create() because at the time
	85	* tracing_map_create() is called, there isn't enough information to
	86	* create the tracing_map_elts. Specifically,the user first needs to
	87	* tell the tracing_map implementation how many fields the
	88	* tracing_map_elts contain, and which types of fields they are (key
	89	* or sum). The user does this via the tracing_map_add_sum_field()
	90	* and tracing_map_add_key_field() functions, following which the user
	91	* calls tracing_map_init() to finish up the tracing map setup. The
	92	* array holding the pointers which make up the pre-allocated pool of
	93	* tracing_map_elts is allocated as a single block and is stored in
	94	* the elts field of struct tracing_map.
	95	*
	96	* There is also a set of structures used for sorting that might
	97	* benefit from some minimal explanation.
	98	*
	99	* struct tracing_map_sort_key is used to drive the sort at any given
	100	* time. By 'any given time' we mean that a different
	101	* tracing_map_sort_key will be used at different times depending on
	102	* whether the sort currently being performed is a primary or a
	103	* secondary sort.
	104	*
	105	* The sort key is very simple, consisting of the field index of the
	106	* tracing_map_elt field to sort on (which the user saved when adding
	107	* the field), and whether the sort should be done in an ascending or
	108	* descending order.
	109	*
	110	* For the convenience of the sorting code, a tracing_map_sort_entry
	111	* is created for each tracing_map_elt, again individually allocated
	112	* to avoid failures that might be expected if allocated as a single
	113	* large array of struct tracing_map_sort_entry.
	114	* tracing_map_sort_entry instances are the objects expected by the
115	* various internal sorting functions, and are also what the user
116	* ultimately receives after calling tracing_map_sort_entries().
117	* Because it doesn't make sense for users to access an unordered and
118	* sparsely populated tracing_map directly, the
119	* tracing_map_sort_entries() function is provided so that users can
120	* retrieve a sorted list of all existing elements. In addition to
121	* the associated tracing_map_elt 'elt' field contained within the
122	* tracing_map_sort_entry, which is the object of interest to the
123	* user, tracing_map_sort_entry objects contain a number of additional
124	* fields which are used for caching and internal purposes and can
125	* safely be ignored.
126	*/
127
128	struct tracing_map_field {
129	tracing_map_cmp_fn_t cmp_fn;
130	union {
131	atomic64_t sum;
132	unsigned int offset;
133	};
134	};
135
136	struct tracing_map_elt {
137	struct tracing_map *map;
138	struct tracing_map_field *fields;
139	void *key;
140	void *private_data;
141	};
142
143	struct tracing_map_entry {
144	u32 key;
145	struct tracing_map_elt *val;
146	};
147
148	struct tracing_map_sort_key {
149	unsigned int field_idx;
150	bool descending;
151	};
152
153	struct tracing_map_sort_entry {
154	void *key;
155	struct tracing_map_elt *elt;
156	bool elt_copied;
157	bool dup;
158	};
159
160	struct tracing_map_array {
161	unsigned int entries_per_page;
162	unsigned int entry_size_shift;
163	unsigned int entry_shift;
164	unsigned int entry_mask;
165	unsigned int n_pages;
166	void **pages;
167	};
168
169	#define TRACING_MAP_ARRAY_ELT(array, idx) \
170	(array->pages[idx >> array->entry_shift] + \
171	((idx & array->entry_mask) << array->entry_size_shift))
172
173	#define TRACING_MAP_ENTRY(array, idx) \
174	((struct tracing_map_entry *)TRACING_MAP_ARRAY_ELT(array, idx))
175
176	#define TRACING_MAP_ELT(array, idx) \
177	((struct tracing_map_elt **)TRACING_MAP_ARRAY_ELT(array, idx))
178
179	struct tracing_map {
180	unsigned int key_size;
181	unsigned int map_bits;
182	unsigned int map_size;
183	unsigned int max_elts;
184	atomic_t next_elt;
185	struct tracing_map_array *elts;
186	struct tracing_map_array *map;
187	const struct tracing_map_ops *ops;
188	void *private_data;
189	struct tracing_map_field fields[TRACING_MAP_FIELDS_MAX];
190	unsigned int n_fields;
191	int key_idx[TRACING_MAP_KEYS_MAX];
192	unsigned int n_keys;
193	struct tracing_map_sort_key sort_key;
194	atomic64_t hits;
195	atomic64_t drops;
196	};
197
198	/**
199	* struct tracing_map_ops - callbacks for tracing_map
200	*
201	* The methods in this structure define callback functions for various
202	* operations on a tracing_map or objects related to a tracing_map.
203	*
204	* For a detailed description of tracing_map_elt objects please see
205	* the overview of tracing_map data structures at the beginning of
206	* this file.
207	*
208	* All the methods below are optional.
209	*
210	* @elt_alloc: When a tracing_map_elt is allocated, this function, if
211	* defined, will be called and gives clients the opportunity to
212	* allocate additional data and attach it to the element
213	* (tracing_map_elt->private_data is meant for that purpose).
214	* Element allocation occurs before tracing begins, when the
215	* tracing_map_init() call is made by client code.
216	*
217	* @elt_copy: At certain points in the lifetime of an element, it may
218	* need to be copied. The copy should include a copy of the
219	* client-allocated data, which can be copied into the 'to'
220	* element from the 'from' element.
221	*
222	* @elt_free: When a tracing_map_elt is freed, this function is called
223	* and allows client-allocated per-element data to be freed.
224	*
225	* @elt_clear: This callback allows per-element client-defined data to
226	* be cleared, if applicable.
227	*
228	* @elt_init: This callback allows per-element client-defined data to
229	* be initialized when used i.e. when the element is actually
230	* claimed by tracing_map_insert() in the context of the map
231	* insertion.
232	*/
233	struct tracing_map_ops {
234	int (elt_alloc)(struct tracing_map_elt elt);
235	void (elt_copy)(struct tracing_map_elt to,
236	struct tracing_map_elt *from);
237	void (elt_free)(struct tracing_map_elt elt);
238	void (elt_clear)(struct tracing_map_elt elt);
239	void (elt_init)(struct tracing_map_elt elt);
240	};
241
242	extern struct tracing_map *
243	tracing_map_create(unsigned int map_bits,
244	unsigned int key_size,
245	const struct tracing_map_ops *ops,
246	void *private_data);
247	extern int tracing_map_init(struct tracing_map *map);
248
249	extern int tracing_map_add_sum_field(struct tracing_map *map);
250	extern int tracing_map_add_key_field(struct tracing_map *map,
251	unsigned int offset,
252	tracing_map_cmp_fn_t cmp_fn);
253
254	extern void tracing_map_destroy(struct tracing_map *map);
255	extern void tracing_map_clear(struct tracing_map *map);
256
257	extern struct tracing_map_elt *
258	tracing_map_insert(struct tracing_map map, void key);
259	extern struct tracing_map_elt *
260	tracing_map_lookup(struct tracing_map map, void key);
261
262	extern tracing_map_cmp_fn_t tracing_map_cmp_num(int field_size,
263	int field_is_signed);
264	extern int tracing_map_cmp_string(void val_a, void val_b);
265	extern int tracing_map_cmp_none(void val_a, void val_b);
266
267	extern void tracing_map_update_sum(struct tracing_map_elt *elt,
268	unsigned int i, u64 n);
269	extern u64 tracing_map_read_sum(struct tracing_map_elt *elt, unsigned int i);
270	extern void tracing_map_set_field_descr(struct tracing_map *map,
271	unsigned int i,
272	unsigned int key_offset,
273	tracing_map_cmp_fn_t cmp_fn);
274	extern int
275	tracing_map_sort_entries(struct tracing_map *map,
276	struct tracing_map_sort_key *sort_keys,
277	unsigned int n_sort_keys,
278	struct tracing_map_sort_entry ***sort_entries);
279
280	extern void
281	tracing_map_destroy_sort_entries(struct tracing_map_sort_entry **entries,
282	unsigned int n_entries);
283	#endif /* __TRACING_MAP_H */