kernel/trace/tracing_map.h - arm/linux - Git at Google

 #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 */
	#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 */