// SPDX-License-Identifier: GPL-2.0
|
/*
|
* tracing_map - lock-free map for tracing
|
*
|
* Copyright (C) 2015 Tom Zanussi <tom.zanussi@linux.intel.com>
|
*
|
* tracing_map implementation inspired by lock-free map algorithms
|
* originated by Dr. Cliff Click:
|
*
|
* http://www.azulsystems.com/blog/cliff/2007-03-26-non-blocking-hashtable
|
* http://www.azulsystems.com/events/javaone_2007/2007_LockFreeHash.pdf
|
*/
|
|
#include <linux/vmalloc.h>
|
#include <linux/jhash.h>
|
#include <linux/slab.h>
|
#include <linux/sort.h>
|
#include <linux/kmemleak.h>
|
|
#include "tracing_map.h"
|
#include "trace.h"
|
|
/*
|
* NOTE: For a detailed description of the data structures used by
|
* these functions (such as tracing_map_elt) please see the overview
|
* of tracing_map data structures at the beginning of tracing_map.h.
|
*/
|
|
/**
|
* tracing_map_update_sum - Add a value to a tracing_map_elt's sum field
|
* @elt: The tracing_map_elt
|
* @i: The index of the given sum associated with the tracing_map_elt
|
* @n: The value to add to the sum
|
*
|
* Add n to sum i associated with the specified tracing_map_elt
|
* instance. The index i is the index returned by the call to
|
* tracing_map_add_sum_field() when the tracing map was set up.
|
*/
|
void tracing_map_update_sum(struct tracing_map_elt *elt, unsigned int i, u64 n)
|
{
|
atomic64_add(n, &elt->fields[i].sum);
|
}
|
|
/**
|
* tracing_map_read_sum - Return the value of a tracing_map_elt's sum field
|
* @elt: The tracing_map_elt
|
* @i: The index of the given sum associated with the tracing_map_elt
|
*
|
* Retrieve the value of the sum i associated with the specified
|
* tracing_map_elt instance. The index i is the index returned by the
|
* call to tracing_map_add_sum_field() when the tracing map was set
|
* up.
|
*
|
* Return: The sum associated with field i for elt.
|
*/
|
u64 tracing_map_read_sum(struct tracing_map_elt *elt, unsigned int i)
|
{
|
return (u64)atomic64_read(&elt->fields[i].sum);
|
}
|
|
/**
|
* tracing_map_set_var - Assign a tracing_map_elt's variable field
|
* @elt: The tracing_map_elt
|
* @i: The index of the given variable associated with the tracing_map_elt
|
* @n: The value to assign
|
*
|
* Assign n to variable i associated with the specified tracing_map_elt
|
* instance. The index i is the index returned by the call to
|
* tracing_map_add_var() when the tracing map was set up.
|
*/
|
void tracing_map_set_var(struct tracing_map_elt *elt, unsigned int i, u64 n)
|
{
|
atomic64_set(&elt->vars[i], n);
|
elt->var_set[i] = true;
|
}
|
|
/**
|
* tracing_map_var_set - Return whether or not a variable has been set
|
* @elt: The tracing_map_elt
|
* @i: The index of the given variable associated with the tracing_map_elt
|
*
|
* Return true if the variable has been set, false otherwise. The
|
* index i is the index returned by the call to tracing_map_add_var()
|
* when the tracing map was set up.
|
*/
|
bool tracing_map_var_set(struct tracing_map_elt *elt, unsigned int i)
|
{
|
return elt->var_set[i];
|
}
|
|
/**
|
* tracing_map_read_var - Return the value of a tracing_map_elt's variable field
|
* @elt: The tracing_map_elt
|
* @i: The index of the given variable associated with the tracing_map_elt
|
*
|
* Retrieve the value of the variable i associated with the specified
|
* tracing_map_elt instance. The index i is the index returned by the
|
* call to tracing_map_add_var() when the tracing map was set
|
* up.
|
*
|
* Return: The variable value associated with field i for elt.
|
*/
|
u64 tracing_map_read_var(struct tracing_map_elt *elt, unsigned int i)
|
{
|
return (u64)atomic64_read(&elt->vars[i]);
|
}
|
|
/**
|
* tracing_map_read_var_once - Return and reset a tracing_map_elt's variable field
|
* @elt: The tracing_map_elt
|
* @i: The index of the given variable associated with the tracing_map_elt
|
*
|
* Retrieve the value of the variable i associated with the specified
|
* tracing_map_elt instance, and reset the variable to the 'not set'
|
* state. The index i is the index returned by the call to
|
* tracing_map_add_var() when the tracing map was set up. The reset
|
* essentially makes the variable a read-once variable if it's only
|
* accessed using this function.
|
*
|
* Return: The variable value associated with field i for elt.
|
*/
|
u64 tracing_map_read_var_once(struct tracing_map_elt *elt, unsigned int i)
|
{
|
elt->var_set[i] = false;
|
return (u64)atomic64_read(&elt->vars[i]);
|
}
|
|
int tracing_map_cmp_string(void *val_a, void *val_b)
|
{
|
char *a = val_a;
|
char *b = val_b;
|
|
return strcmp(a, b);
|
}
|
|
int tracing_map_cmp_none(void *val_a, void *val_b)
|
{
|
return 0;
|
}
|
|
static int tracing_map_cmp_atomic64(void *val_a, void *val_b)
|
{
|
u64 a = atomic64_read((atomic64_t *)val_a);
|
u64 b = atomic64_read((atomic64_t *)val_b);
|
|
return (a > b) ? 1 : ((a < b) ? -1 : 0);
|
}
|
|
#define DEFINE_TRACING_MAP_CMP_FN(type) \
|
static int tracing_map_cmp_##type(void *val_a, void *val_b) \
|
{ \
|
type a = (type)(*(u64 *)val_a); \
|
type b = (type)(*(u64 *)val_b); \
|
\
|
return (a > b) ? 1 : ((a < b) ? -1 : 0); \
|
}
|
|
DEFINE_TRACING_MAP_CMP_FN(s64);
|
DEFINE_TRACING_MAP_CMP_FN(u64);
|
DEFINE_TRACING_MAP_CMP_FN(s32);
|
DEFINE_TRACING_MAP_CMP_FN(u32);
|
DEFINE_TRACING_MAP_CMP_FN(s16);
|
DEFINE_TRACING_MAP_CMP_FN(u16);
|
DEFINE_TRACING_MAP_CMP_FN(s8);
|
DEFINE_TRACING_MAP_CMP_FN(u8);
|
|
tracing_map_cmp_fn_t tracing_map_cmp_num(int field_size,
|
int field_is_signed)
|
{
|
tracing_map_cmp_fn_t fn = tracing_map_cmp_none;
|
|
switch (field_size) {
|
case 8:
|
if (field_is_signed)
|
fn = tracing_map_cmp_s64;
|
else
|
fn = tracing_map_cmp_u64;
|
break;
|
case 4:
|
if (field_is_signed)
|
fn = tracing_map_cmp_s32;
|
else
|
fn = tracing_map_cmp_u32;
|
break;
|
case 2:
|
if (field_is_signed)
|
fn = tracing_map_cmp_s16;
|
else
|
fn = tracing_map_cmp_u16;
|
break;
|
case 1:
|
if (field_is_signed)
|
fn = tracing_map_cmp_s8;
|
else
|
fn = tracing_map_cmp_u8;
|
break;
|
}
|
|
return fn;
|
}
|
|
static int tracing_map_add_field(struct tracing_map *map,
|
tracing_map_cmp_fn_t cmp_fn)
|
{
|
int ret = -EINVAL;
|
|
if (map->n_fields < TRACING_MAP_FIELDS_MAX) {
|
ret = map->n_fields;
|
map->fields[map->n_fields++].cmp_fn = cmp_fn;
|
}
|
|
return ret;
|
}
|
|
/**
|
* tracing_map_add_sum_field - Add a field describing a tracing_map sum
|
* @map: The tracing_map
|
*
|
* Add a sum field to the key and return the index identifying it in
|
* the map and associated tracing_map_elts. This is the index used
|
* for instance to update a sum for a particular tracing_map_elt using
|
* tracing_map_update_sum() or reading it via tracing_map_read_sum().
|
*
|
* Return: The index identifying the field in the map and associated
|
* tracing_map_elts, or -EINVAL on error.
|
*/
|
int tracing_map_add_sum_field(struct tracing_map *map)
|
{
|
return tracing_map_add_field(map, tracing_map_cmp_atomic64);
|
}
|
|
/**
|
* tracing_map_add_var - Add a field describing a tracing_map var
|
* @map: The tracing_map
|
*
|
* Add a var to the map and return the index identifying it in the map
|
* and associated tracing_map_elts. This is the index used for
|
* instance to update a var for a particular tracing_map_elt using
|
* tracing_map_update_var() or reading it via tracing_map_read_var().
|
*
|
* Return: The index identifying the var in the map and associated
|
* tracing_map_elts, or -EINVAL on error.
|
*/
|
int tracing_map_add_var(struct tracing_map *map)
|
{
|
int ret = -EINVAL;
|
|
if (map->n_vars < TRACING_MAP_VARS_MAX)
|
ret = map->n_vars++;
|
|
return ret;
|
}
|
|
/**
|
* tracing_map_add_key_field - Add a field describing a tracing_map key
|
* @map: The tracing_map
|
* @offset: The offset within the key
|
* @cmp_fn: The comparison function that will be used to sort on the key
|
*
|
* Let the map know there is a key and that if it's used as a sort key
|
* to use cmp_fn.
|
*
|
* A key can be a subset of a compound key; for that purpose, the
|
* offset param is used to describe where within the compound key
|
* the key referenced by this key field resides.
|
*
|
* Return: The index identifying the field in the map and associated
|
* tracing_map_elts, or -EINVAL on error.
|
*/
|
int tracing_map_add_key_field(struct tracing_map *map,
|
unsigned int offset,
|
tracing_map_cmp_fn_t cmp_fn)
|
|
{
|
int idx = tracing_map_add_field(map, cmp_fn);
|
|
if (idx < 0)
|
return idx;
|
|
map->fields[idx].offset = offset;
|
|
map->key_idx[map->n_keys++] = idx;
|
|
return idx;
|
}
|
|
static void tracing_map_array_clear(struct tracing_map_array *a)
|
{
|
unsigned int i;
|
|
if (!a->pages)
|
return;
|
|
for (i = 0; i < a->n_pages; i++)
|
memset(a->pages[i], 0, PAGE_SIZE);
|
}
|
|
static void tracing_map_array_free(struct tracing_map_array *a)
|
{
|
unsigned int i;
|
|
if (!a)
|
return;
|
|
if (!a->pages)
|
goto free;
|
|
for (i = 0; i < a->n_pages; i++) {
|
if (!a->pages[i])
|
break;
|
kmemleak_free(a->pages[i]);
|
free_page((unsigned long)a->pages[i]);
|
}
|
|
kfree(a->pages);
|
|
free:
|
kfree(a);
|
}
|
|
static struct tracing_map_array *tracing_map_array_alloc(unsigned int n_elts,
|
unsigned int entry_size)
|
{
|
struct tracing_map_array *a;
|
unsigned int i;
|
|
a = kzalloc(sizeof(*a), GFP_KERNEL);
|
if (!a)
|
return NULL;
|
|
a->entry_size_shift = fls(roundup_pow_of_two(entry_size) - 1);
|
a->entries_per_page = PAGE_SIZE / (1 << a->entry_size_shift);
|
a->n_pages = n_elts / a->entries_per_page;
|
if (!a->n_pages)
|
a->n_pages = 1;
|
a->entry_shift = fls(a->entries_per_page) - 1;
|
a->entry_mask = (1 << a->entry_shift) - 1;
|
|
a->pages = kcalloc(a->n_pages, sizeof(void *), GFP_KERNEL);
|
if (!a->pages)
|
goto free;
|
|
for (i = 0; i < a->n_pages; i++) {
|
a->pages[i] = (void *)get_zeroed_page(GFP_KERNEL);
|
if (!a->pages[i])
|
goto free;
|
kmemleak_alloc(a->pages[i], PAGE_SIZE, 1, GFP_KERNEL);
|
}
|
out:
|
return a;
|
free:
|
tracing_map_array_free(a);
|
a = NULL;
|
|
goto out;
|
}
|
|
static void tracing_map_elt_clear(struct tracing_map_elt *elt)
|
{
|
unsigned i;
|
|
for (i = 0; i < elt->map->n_fields; i++)
|
if (elt->fields[i].cmp_fn == tracing_map_cmp_atomic64)
|
atomic64_set(&elt->fields[i].sum, 0);
|
|
for (i = 0; i < elt->map->n_vars; i++) {
|
atomic64_set(&elt->vars[i], 0);
|
elt->var_set[i] = false;
|
}
|
|
if (elt->map->ops && elt->map->ops->elt_clear)
|
elt->map->ops->elt_clear(elt);
|
}
|
|
static void tracing_map_elt_init_fields(struct tracing_map_elt *elt)
|
{
|
unsigned int i;
|
|
tracing_map_elt_clear(elt);
|
|
for (i = 0; i < elt->map->n_fields; i++) {
|
elt->fields[i].cmp_fn = elt->map->fields[i].cmp_fn;
|
|
if (elt->fields[i].cmp_fn != tracing_map_cmp_atomic64)
|
elt->fields[i].offset = elt->map->fields[i].offset;
|
}
|
}
|
|
static void tracing_map_elt_free(struct tracing_map_elt *elt)
|
{
|
if (!elt)
|
return;
|
|
if (elt->map->ops && elt->map->ops->elt_free)
|
elt->map->ops->elt_free(elt);
|
kfree(elt->fields);
|
kfree(elt->vars);
|
kfree(elt->var_set);
|
kfree(elt->key);
|
kfree(elt);
|
}
|
|
static struct tracing_map_elt *tracing_map_elt_alloc(struct tracing_map *map)
|
{
|
struct tracing_map_elt *elt;
|
int err = 0;
|
|
elt = kzalloc(sizeof(*elt), GFP_KERNEL);
|
if (!elt)
|
return ERR_PTR(-ENOMEM);
|
|
elt->map = map;
|
|
elt->key = kzalloc(map->key_size, GFP_KERNEL);
|
if (!elt->key) {
|
err = -ENOMEM;
|
goto free;
|
}
|
|
elt->fields = kcalloc(map->n_fields, sizeof(*elt->fields), GFP_KERNEL);
|
if (!elt->fields) {
|
err = -ENOMEM;
|
goto free;
|
}
|
|
elt->vars = kcalloc(map->n_vars, sizeof(*elt->vars), GFP_KERNEL);
|
if (!elt->vars) {
|
err = -ENOMEM;
|
goto free;
|
}
|
|
elt->var_set = kcalloc(map->n_vars, sizeof(*elt->var_set), GFP_KERNEL);
|
if (!elt->var_set) {
|
err = -ENOMEM;
|
goto free;
|
}
|
|
tracing_map_elt_init_fields(elt);
|
|
if (map->ops && map->ops->elt_alloc) {
|
err = map->ops->elt_alloc(elt);
|
if (err)
|
goto free;
|
}
|
return elt;
|
free:
|
tracing_map_elt_free(elt);
|
|
return ERR_PTR(err);
|
}
|
|
static struct tracing_map_elt *get_free_elt(struct tracing_map *map)
|
{
|
struct tracing_map_elt *elt = NULL;
|
int idx;
|
|
idx = atomic_inc_return(&map->next_elt);
|
if (idx < map->max_elts) {
|
elt = *(TRACING_MAP_ELT(map->elts, idx));
|
if (map->ops && map->ops->elt_init)
|
map->ops->elt_init(elt);
|
}
|
|
return elt;
|
}
|
|
static void tracing_map_free_elts(struct tracing_map *map)
|
{
|
unsigned int i;
|
|
if (!map->elts)
|
return;
|
|
for (i = 0; i < map->max_elts; i++) {
|
tracing_map_elt_free(*(TRACING_MAP_ELT(map->elts, i)));
|
*(TRACING_MAP_ELT(map->elts, i)) = NULL;
|
}
|
|
tracing_map_array_free(map->elts);
|
map->elts = NULL;
|
}
|
|
static int tracing_map_alloc_elts(struct tracing_map *map)
|
{
|
unsigned int i;
|
|
map->elts = tracing_map_array_alloc(map->max_elts,
|
sizeof(struct tracing_map_elt *));
|
if (!map->elts)
|
return -ENOMEM;
|
|
for (i = 0; i < map->max_elts; i++) {
|
*(TRACING_MAP_ELT(map->elts, i)) = tracing_map_elt_alloc(map);
|
if (IS_ERR(*(TRACING_MAP_ELT(map->elts, i)))) {
|
*(TRACING_MAP_ELT(map->elts, i)) = NULL;
|
tracing_map_free_elts(map);
|
|
return -ENOMEM;
|
}
|
}
|
|
return 0;
|
}
|
|
static inline bool keys_match(void *key, void *test_key, unsigned key_size)
|
{
|
bool match = true;
|
|
if (memcmp(key, test_key, key_size))
|
match = false;
|
|
return match;
|
}
|
|
static inline struct tracing_map_elt *
|
__tracing_map_insert(struct tracing_map *map, void *key, bool lookup_only)
|
{
|
u32 idx, key_hash, test_key;
|
int dup_try = 0;
|
struct tracing_map_entry *entry;
|
struct tracing_map_elt *val;
|
|
key_hash = jhash(key, map->key_size, 0);
|
if (key_hash == 0)
|
key_hash = 1;
|
idx = key_hash >> (32 - (map->map_bits + 1));
|
|
while (1) {
|
idx &= (map->map_size - 1);
|
entry = TRACING_MAP_ENTRY(map->map, idx);
|
test_key = entry->key;
|
|
if (test_key && test_key == key_hash) {
|
val = READ_ONCE(entry->val);
|
if (val &&
|
keys_match(key, val->key, map->key_size)) {
|
if (!lookup_only)
|
atomic64_inc(&map->hits);
|
return val;
|
} else if (unlikely(!val)) {
|
/*
|
* The key is present. But, val (pointer to elt
|
* struct) is still NULL. which means some other
|
* thread is in the process of inserting an
|
* element.
|
*
|
* On top of that, it's key_hash is same as the
|
* one being inserted right now. So, it's
|
* possible that the element has the same
|
* key as well.
|
*/
|
|
dup_try++;
|
if (dup_try > map->map_size) {
|
atomic64_inc(&map->drops);
|
break;
|
}
|
continue;
|
}
|
}
|
|
if (!test_key) {
|
if (lookup_only)
|
break;
|
|
if (!cmpxchg(&entry->key, 0, key_hash)) {
|
struct tracing_map_elt *elt;
|
|
elt = get_free_elt(map);
|
if (!elt) {
|
atomic64_inc(&map->drops);
|
entry->key = 0;
|
break;
|
}
|
|
memcpy(elt->key, key, map->key_size);
|
entry->val = elt;
|
atomic64_inc(&map->hits);
|
|
return entry->val;
|
} else {
|
/*
|
* cmpxchg() failed. Loop around once
|
* more to check what key was inserted.
|
*/
|
dup_try++;
|
continue;
|
}
|
}
|
|
idx++;
|
}
|
|
return NULL;
|
}
|
|
/**
|
* tracing_map_insert - Insert key and/or retrieve val from a tracing_map
|
* @map: The tracing_map to insert into
|
* @key: The key to insert
|
*
|
* Inserts a key into a tracing_map and creates and returns a new
|
* tracing_map_elt for it, or if the key has already been inserted by
|
* a previous call, returns the tracing_map_elt already associated
|
* with it. When the map was created, the number of elements to be
|
* allocated for the map was specified (internally maintained as
|
* 'max_elts' in struct tracing_map), and that number of
|
* tracing_map_elts was created by tracing_map_init(). This is the
|
* pre-allocated pool of tracing_map_elts that tracing_map_insert()
|
* will allocate from when adding new keys. Once that pool is
|
* exhausted, tracing_map_insert() is useless and will return NULL to
|
* signal that state. There are two user-visible tracing_map
|
* variables, 'hits' and 'drops', which are updated by this function.
|
* Every time an element is either successfully inserted or retrieved,
|
* the 'hits' value is incrememented. Every time an element insertion
|
* fails, the 'drops' value is incremented.
|
*
|
* This is a lock-free tracing map insertion function implementing a
|
* modified form of Cliff Click's basic insertion algorithm. It
|
* requires the table size be a power of two. To prevent any
|
* possibility of an infinite loop we always make the internal table
|
* size double the size of the requested table size (max_elts * 2).
|
* Likewise, we never reuse a slot or resize or delete elements - when
|
* we've reached max_elts entries, we simply return NULL once we've
|
* run out of entries. Readers can at any point in time traverse the
|
* tracing map and safely access the key/val pairs.
|
*
|
* Return: the tracing_map_elt pointer val associated with the key.
|
* If this was a newly inserted key, the val will be a newly allocated
|
* and associated tracing_map_elt pointer val. If the key wasn't
|
* found and the pool of tracing_map_elts has been exhausted, NULL is
|
* returned and no further insertions will succeed.
|
*/
|
struct tracing_map_elt *tracing_map_insert(struct tracing_map *map, void *key)
|
{
|
return __tracing_map_insert(map, key, false);
|
}
|
|
/**
|
* tracing_map_lookup - Retrieve val from a tracing_map
|
* @map: The tracing_map to perform the lookup on
|
* @key: The key to look up
|
*
|
* Looks up key in tracing_map and if found returns the matching
|
* tracing_map_elt. This is a lock-free lookup; see
|
* tracing_map_insert() for details on tracing_map and how it works.
|
* Every time an element is retrieved, the 'hits' value is
|
* incrememented. There is one user-visible tracing_map variable,
|
* 'hits', which is updated by this function. Every time an element
|
* is successfully retrieved, the 'hits' value is incrememented. The
|
* 'drops' value is never updated by this function.
|
*
|
* Return: the tracing_map_elt pointer val associated with the key.
|
* If the key wasn't found, NULL is returned.
|
*/
|
struct tracing_map_elt *tracing_map_lookup(struct tracing_map *map, void *key)
|
{
|
return __tracing_map_insert(map, key, true);
|
}
|
|
/**
|
* tracing_map_destroy - Destroy a tracing_map
|
* @map: The tracing_map to destroy
|
*
|
* Frees a tracing_map along with its associated array of
|
* tracing_map_elts.
|
*
|
* Callers should make sure there are no readers or writers actively
|
* reading or inserting into the map before calling this.
|
*/
|
void tracing_map_destroy(struct tracing_map *map)
|
{
|
if (!map)
|
return;
|
|
tracing_map_free_elts(map);
|
|
tracing_map_array_free(map->map);
|
kfree(map);
|
}
|
|
/**
|
* tracing_map_clear - Clear a tracing_map
|
* @map: The tracing_map to clear
|
*
|
* Resets the tracing map to a cleared or initial state. The
|
* tracing_map_elts are all cleared, and the array of struct
|
* tracing_map_entry is reset to an initialized state.
|
*
|
* Callers should make sure there are no writers actively inserting
|
* into the map before calling this.
|
*/
|
void tracing_map_clear(struct tracing_map *map)
|
{
|
unsigned int i;
|
|
atomic_set(&map->next_elt, -1);
|
atomic64_set(&map->hits, 0);
|
atomic64_set(&map->drops, 0);
|
|
tracing_map_array_clear(map->map);
|
|
for (i = 0; i < map->max_elts; i++)
|
tracing_map_elt_clear(*(TRACING_MAP_ELT(map->elts, i)));
|
}
|
|
static void set_sort_key(struct tracing_map *map,
|
struct tracing_map_sort_key *sort_key)
|
{
|
map->sort_key = *sort_key;
|
}
|
|
/**
|
* tracing_map_create - Create a lock-free map and element pool
|
* @map_bits: The size of the map (2 ** map_bits)
|
* @key_size: The size of the key for the map in bytes
|
* @ops: Optional client-defined tracing_map_ops instance
|
* @private_data: Client data associated with the map
|
*
|
* Creates and sets up a map to contain 2 ** map_bits number of
|
* elements (internally maintained as 'max_elts' in struct
|
* tracing_map). Before using, map fields should be added to the map
|
* with tracing_map_add_sum_field() and tracing_map_add_key_field().
|
* tracing_map_init() should then be called to allocate the array of
|
* tracing_map_elts, in order to avoid allocating anything in the map
|
* insertion path. The user-specified map size reflects the maximum
|
* number of elements that can be contained in the table requested by
|
* the user - internally we double that in order to keep the table
|
* sparse and keep collisions manageable.
|
*
|
* A tracing_map is a special-purpose map designed to aggregate or
|
* 'sum' one or more values associated with a specific object of type
|
* tracing_map_elt, which is attached by the map to a given key.
|
*
|
* tracing_map_create() sets up the map itself, and provides
|
* operations for inserting tracing_map_elts, but doesn't allocate the
|
* tracing_map_elts themselves, or provide a means for describing the
|
* keys or sums associated with the tracing_map_elts. All
|
* tracing_map_elts for a given map have the same set of sums and
|
* keys, which are defined by the client using the functions
|
* tracing_map_add_key_field() and tracing_map_add_sum_field(). Once
|
* the fields are defined, the pool of elements allocated for the map
|
* can be created, which occurs when the client code calls
|
* tracing_map_init().
|
*
|
* When tracing_map_init() returns, tracing_map_elt elements can be
|
* inserted into the map using tracing_map_insert(). When called,
|
* tracing_map_insert() grabs a free tracing_map_elt from the pool, or
|
* finds an existing match in the map and in either case returns it.
|
* The client can then use tracing_map_update_sum() and
|
* tracing_map_read_sum() to update or read a given sum field for the
|
* tracing_map_elt.
|
*
|
* The client can at any point retrieve and traverse the current set
|
* of inserted tracing_map_elts in a tracing_map, via
|
* tracing_map_sort_entries(). Sorting can be done on any field,
|
* including keys.
|
*
|
* See tracing_map.h for a description of tracing_map_ops.
|
*
|
* Return: the tracing_map pointer if successful, ERR_PTR if not.
|
*/
|
struct tracing_map *tracing_map_create(unsigned int map_bits,
|
unsigned int key_size,
|
const struct tracing_map_ops *ops,
|
void *private_data)
|
{
|
struct tracing_map *map;
|
unsigned int i;
|
|
if (map_bits < TRACING_MAP_BITS_MIN ||
|
map_bits > TRACING_MAP_BITS_MAX)
|
return ERR_PTR(-EINVAL);
|
|
map = kzalloc(sizeof(*map), GFP_KERNEL);
|
if (!map)
|
return ERR_PTR(-ENOMEM);
|
|
map->map_bits = map_bits;
|
map->max_elts = (1 << map_bits);
|
atomic_set(&map->next_elt, -1);
|
|
map->map_size = (1 << (map_bits + 1));
|
map->ops = ops;
|
|
map->private_data = private_data;
|
|
map->map = tracing_map_array_alloc(map->map_size,
|
sizeof(struct tracing_map_entry));
|
if (!map->map)
|
goto free;
|
|
map->key_size = key_size;
|
for (i = 0; i < TRACING_MAP_KEYS_MAX; i++)
|
map->key_idx[i] = -1;
|
out:
|
return map;
|
free:
|
tracing_map_destroy(map);
|
map = ERR_PTR(-ENOMEM);
|
|
goto out;
|
}
|
|
/**
|
* tracing_map_init - Allocate and clear a map's tracing_map_elts
|
* @map: The tracing_map to initialize
|
*
|
* Allocates a clears a pool of tracing_map_elts equal to the
|
* user-specified size of 2 ** map_bits (internally maintained as
|
* 'max_elts' in struct tracing_map). Before using, the map fields
|
* should be added to the map with tracing_map_add_sum_field() and
|
* tracing_map_add_key_field(). tracing_map_init() should then be
|
* called to allocate the array of tracing_map_elts, in order to avoid
|
* allocating anything in the map insertion path. The user-specified
|
* map size reflects the max number of elements requested by the user
|
* - internally we double that in order to keep the table sparse and
|
* keep collisions manageable.
|
*
|
* See tracing_map.h for a description of tracing_map_ops.
|
*
|
* Return: the tracing_map pointer if successful, ERR_PTR if not.
|
*/
|
int tracing_map_init(struct tracing_map *map)
|
{
|
int err;
|
|
if (map->n_fields < 2)
|
return -EINVAL; /* need at least 1 key and 1 val */
|
|
err = tracing_map_alloc_elts(map);
|
if (err)
|
return err;
|
|
tracing_map_clear(map);
|
|
return err;
|
}
|
|
static int cmp_entries_dup(const void *A, const void *B)
|
{
|
const struct tracing_map_sort_entry *a, *b;
|
int ret = 0;
|
|
a = *(const struct tracing_map_sort_entry **)A;
|
b = *(const struct tracing_map_sort_entry **)B;
|
|
if (memcmp(a->key, b->key, a->elt->map->key_size))
|
ret = 1;
|
|
return ret;
|
}
|
|
static int cmp_entries_sum(const void *A, const void *B)
|
{
|
const struct tracing_map_elt *elt_a, *elt_b;
|
const struct tracing_map_sort_entry *a, *b;
|
struct tracing_map_sort_key *sort_key;
|
struct tracing_map_field *field;
|
tracing_map_cmp_fn_t cmp_fn;
|
void *val_a, *val_b;
|
int ret = 0;
|
|
a = *(const struct tracing_map_sort_entry **)A;
|
b = *(const struct tracing_map_sort_entry **)B;
|
|
elt_a = a->elt;
|
elt_b = b->elt;
|
|
sort_key = &elt_a->map->sort_key;
|
|
field = &elt_a->fields[sort_key->field_idx];
|
cmp_fn = field->cmp_fn;
|
|
val_a = &elt_a->fields[sort_key->field_idx].sum;
|
val_b = &elt_b->fields[sort_key->field_idx].sum;
|
|
ret = cmp_fn(val_a, val_b);
|
if (sort_key->descending)
|
ret = -ret;
|
|
return ret;
|
}
|
|
static int cmp_entries_key(const void *A, const void *B)
|
{
|
const struct tracing_map_elt *elt_a, *elt_b;
|
const struct tracing_map_sort_entry *a, *b;
|
struct tracing_map_sort_key *sort_key;
|
struct tracing_map_field *field;
|
tracing_map_cmp_fn_t cmp_fn;
|
void *val_a, *val_b;
|
int ret = 0;
|
|
a = *(const struct tracing_map_sort_entry **)A;
|
b = *(const struct tracing_map_sort_entry **)B;
|
|
elt_a = a->elt;
|
elt_b = b->elt;
|
|
sort_key = &elt_a->map->sort_key;
|
|
field = &elt_a->fields[sort_key->field_idx];
|
|
cmp_fn = field->cmp_fn;
|
|
val_a = elt_a->key + field->offset;
|
val_b = elt_b->key + field->offset;
|
|
ret = cmp_fn(val_a, val_b);
|
if (sort_key->descending)
|
ret = -ret;
|
|
return ret;
|
}
|
|
static void destroy_sort_entry(struct tracing_map_sort_entry *entry)
|
{
|
if (!entry)
|
return;
|
|
if (entry->elt_copied)
|
tracing_map_elt_free(entry->elt);
|
|
kfree(entry);
|
}
|
|
/**
|
* tracing_map_destroy_sort_entries - Destroy an array of sort entries
|
* @entries: The entries to destroy
|
* @n_entries: The number of entries in the array
|
*
|
* Destroy the elements returned by a tracing_map_sort_entries() call.
|
*/
|
void tracing_map_destroy_sort_entries(struct tracing_map_sort_entry **entries,
|
unsigned int n_entries)
|
{
|
unsigned int i;
|
|
for (i = 0; i < n_entries; i++)
|
destroy_sort_entry(entries[i]);
|
|
vfree(entries);
|
}
|
|
static struct tracing_map_sort_entry *
|
create_sort_entry(void *key, struct tracing_map_elt *elt)
|
{
|
struct tracing_map_sort_entry *sort_entry;
|
|
sort_entry = kzalloc(sizeof(*sort_entry), GFP_KERNEL);
|
if (!sort_entry)
|
return NULL;
|
|
sort_entry->key = key;
|
sort_entry->elt = elt;
|
|
return sort_entry;
|
}
|
|
static void detect_dups(struct tracing_map_sort_entry **sort_entries,
|
int n_entries, unsigned int key_size)
|
{
|
unsigned int dups = 0, total_dups = 0;
|
int i;
|
void *key;
|
|
if (n_entries < 2)
|
return;
|
|
sort(sort_entries, n_entries, sizeof(struct tracing_map_sort_entry *),
|
(int (*)(const void *, const void *))cmp_entries_dup, NULL);
|
|
key = sort_entries[0]->key;
|
for (i = 1; i < n_entries; i++) {
|
if (!memcmp(sort_entries[i]->key, key, key_size)) {
|
dups++; total_dups++;
|
continue;
|
}
|
key = sort_entries[i]->key;
|
dups = 0;
|
}
|
|
WARN_ONCE(total_dups > 0,
|
"Duplicates detected: %d\n", total_dups);
|
}
|
|
static bool is_key(struct tracing_map *map, unsigned int field_idx)
|
{
|
unsigned int i;
|
|
for (i = 0; i < map->n_keys; i++)
|
if (map->key_idx[i] == field_idx)
|
return true;
|
return false;
|
}
|
|
static void sort_secondary(struct tracing_map *map,
|
const struct tracing_map_sort_entry **entries,
|
unsigned int n_entries,
|
struct tracing_map_sort_key *primary_key,
|
struct tracing_map_sort_key *secondary_key)
|
{
|
int (*primary_fn)(const void *, const void *);
|
int (*secondary_fn)(const void *, const void *);
|
unsigned i, start = 0, n_sub = 1;
|
|
if (is_key(map, primary_key->field_idx))
|
primary_fn = cmp_entries_key;
|
else
|
primary_fn = cmp_entries_sum;
|
|
if (is_key(map, secondary_key->field_idx))
|
secondary_fn = cmp_entries_key;
|
else
|
secondary_fn = cmp_entries_sum;
|
|
for (i = 0; i < n_entries - 1; i++) {
|
const struct tracing_map_sort_entry **a = &entries[i];
|
const struct tracing_map_sort_entry **b = &entries[i + 1];
|
|
if (primary_fn(a, b) == 0) {
|
n_sub++;
|
if (i < n_entries - 2)
|
continue;
|
}
|
|
if (n_sub < 2) {
|
start = i + 1;
|
n_sub = 1;
|
continue;
|
}
|
|
set_sort_key(map, secondary_key);
|
sort(&entries[start], n_sub,
|
sizeof(struct tracing_map_sort_entry *),
|
(int (*)(const void *, const void *))secondary_fn, NULL);
|
set_sort_key(map, primary_key);
|
|
start = i + 1;
|
n_sub = 1;
|
}
|
}
|
|
/**
|
* tracing_map_sort_entries - Sort the current set of tracing_map_elts in a map
|
* @map: The tracing_map
|
* @sort_key: The sort key to use for sorting
|
* @sort_entries: outval: pointer to allocated and sorted array of entries
|
*
|
* tracing_map_sort_entries() sorts the current set of entries in the
|
* map and returns the list of tracing_map_sort_entries containing
|
* them to the client in the sort_entries param. The client can
|
* access the struct tracing_map_elt element of interest directly as
|
* the 'elt' field of a returned struct tracing_map_sort_entry object.
|
*
|
* The sort_key has only two fields: idx and descending. 'idx' refers
|
* to the index of the field added via tracing_map_add_sum_field() or
|
* tracing_map_add_key_field() when the tracing_map was initialized.
|
* 'descending' is a flag that if set reverses the sort order, which
|
* by default is ascending.
|
*
|
* The client should not hold on to the returned array but should use
|
* it and call tracing_map_destroy_sort_entries() when done.
|
*
|
* Return: the number of sort_entries in the struct tracing_map_sort_entry
|
* array, negative on error
|
*/
|
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)
|
{
|
int (*cmp_entries_fn)(const void *, const void *);
|
struct tracing_map_sort_entry *sort_entry, **entries;
|
int i, n_entries, ret;
|
|
entries = vmalloc(array_size(sizeof(sort_entry), map->max_elts));
|
if (!entries)
|
return -ENOMEM;
|
|
for (i = 0, n_entries = 0; i < map->map_size; i++) {
|
struct tracing_map_entry *entry;
|
|
entry = TRACING_MAP_ENTRY(map->map, i);
|
|
if (!entry->key || !entry->val)
|
continue;
|
|
entries[n_entries] = create_sort_entry(entry->val->key,
|
entry->val);
|
if (!entries[n_entries++]) {
|
ret = -ENOMEM;
|
goto free;
|
}
|
}
|
|
if (n_entries == 0) {
|
ret = 0;
|
goto free;
|
}
|
|
if (n_entries == 1) {
|
*sort_entries = entries;
|
return 1;
|
}
|
|
detect_dups(entries, n_entries, map->key_size);
|
|
if (is_key(map, sort_keys[0].field_idx))
|
cmp_entries_fn = cmp_entries_key;
|
else
|
cmp_entries_fn = cmp_entries_sum;
|
|
set_sort_key(map, &sort_keys[0]);
|
|
sort(entries, n_entries, sizeof(struct tracing_map_sort_entry *),
|
(int (*)(const void *, const void *))cmp_entries_fn, NULL);
|
|
if (n_sort_keys > 1)
|
sort_secondary(map,
|
(const struct tracing_map_sort_entry **)entries,
|
n_entries,
|
&sort_keys[0],
|
&sort_keys[1]);
|
|
*sort_entries = entries;
|
|
return n_entries;
|
free:
|
tracing_map_destroy_sort_entries(entries, n_entries);
|
|
return ret;
|
}
|
