798 lines
20 KiB
C
798 lines
20 KiB
C
/*
|
|
* Resizable, Scalable, Concurrent Hash Table
|
|
*
|
|
* Copyright (c) 2014 Thomas Graf <tgraf@suug.ch>
|
|
* Copyright (c) 2008-2014 Patrick McHardy <kaber@trash.net>
|
|
*
|
|
* Based on the following paper:
|
|
* https://www.usenix.org/legacy/event/atc11/tech/final_files/Triplett.pdf
|
|
*
|
|
* Code partially derived from nft_hash
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 as
|
|
* published by the Free Software Foundation.
|
|
*/
|
|
|
|
#include <linux/kernel.h>
|
|
#include <linux/init.h>
|
|
#include <linux/log2.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/vmalloc.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/hash.h>
|
|
#include <linux/random.h>
|
|
#include <linux/rhashtable.h>
|
|
|
|
#define HASH_DEFAULT_SIZE 64UL
|
|
#define HASH_MIN_SIZE 4UL
|
|
|
|
#define ASSERT_RHT_MUTEX(HT) BUG_ON(!lockdep_rht_mutex_is_held(HT))
|
|
|
|
#ifdef CONFIG_PROVE_LOCKING
|
|
int lockdep_rht_mutex_is_held(const struct rhashtable *ht)
|
|
{
|
|
return ht->p.mutex_is_held();
|
|
}
|
|
EXPORT_SYMBOL_GPL(lockdep_rht_mutex_is_held);
|
|
#endif
|
|
|
|
static void *rht_obj(const struct rhashtable *ht, const struct rhash_head *he)
|
|
{
|
|
return (void *) he - ht->p.head_offset;
|
|
}
|
|
|
|
static u32 __hashfn(const struct rhashtable *ht, const void *key,
|
|
u32 len, u32 hsize)
|
|
{
|
|
u32 h;
|
|
|
|
h = ht->p.hashfn(key, len, ht->p.hash_rnd);
|
|
|
|
return h & (hsize - 1);
|
|
}
|
|
|
|
/**
|
|
* rhashtable_hashfn - compute hash for key of given length
|
|
* @ht: hash table to compute for
|
|
* @key: pointer to key
|
|
* @len: length of key
|
|
*
|
|
* Computes the hash value using the hash function provided in the 'hashfn'
|
|
* of struct rhashtable_params. The returned value is guaranteed to be
|
|
* smaller than the number of buckets in the hash table.
|
|
*
|
|
* The caller must ensure that no concurrent table mutations occur.
|
|
*/
|
|
u32 rhashtable_hashfn(const struct rhashtable *ht, const void *key, u32 len)
|
|
{
|
|
struct bucket_table *tbl = rht_dereference_rcu(ht->tbl, ht);
|
|
|
|
return __hashfn(ht, key, len, tbl->size);
|
|
}
|
|
EXPORT_SYMBOL_GPL(rhashtable_hashfn);
|
|
|
|
static u32 obj_hashfn(const struct rhashtable *ht, const void *ptr, u32 hsize)
|
|
{
|
|
if (unlikely(!ht->p.key_len)) {
|
|
u32 h;
|
|
|
|
h = ht->p.obj_hashfn(ptr, ht->p.hash_rnd);
|
|
|
|
return h & (hsize - 1);
|
|
}
|
|
|
|
return __hashfn(ht, ptr + ht->p.key_offset, ht->p.key_len, hsize);
|
|
}
|
|
|
|
/**
|
|
* rhashtable_obj_hashfn - compute hash for hashed object
|
|
* @ht: hash table to compute for
|
|
* @ptr: pointer to hashed object
|
|
*
|
|
* Computes the hash value using the hash function `hashfn` respectively
|
|
* 'obj_hashfn' depending on whether the hash table is set up to work with
|
|
* a fixed length key. The returned value is guaranteed to be smaller than
|
|
* the number of buckets in the hash table.
|
|
*
|
|
* The caller must ensure that no concurrent table mutations occur.
|
|
*/
|
|
u32 rhashtable_obj_hashfn(const struct rhashtable *ht, void *ptr)
|
|
{
|
|
struct bucket_table *tbl = rht_dereference_rcu(ht->tbl, ht);
|
|
|
|
return obj_hashfn(ht, ptr, tbl->size);
|
|
}
|
|
EXPORT_SYMBOL_GPL(rhashtable_obj_hashfn);
|
|
|
|
static u32 head_hashfn(const struct rhashtable *ht,
|
|
const struct rhash_head *he, u32 hsize)
|
|
{
|
|
return obj_hashfn(ht, rht_obj(ht, he), hsize);
|
|
}
|
|
|
|
static struct bucket_table *bucket_table_alloc(size_t nbuckets, gfp_t flags)
|
|
{
|
|
struct bucket_table *tbl;
|
|
size_t size;
|
|
|
|
size = sizeof(*tbl) + nbuckets * sizeof(tbl->buckets[0]);
|
|
tbl = kzalloc(size, flags);
|
|
if (tbl == NULL)
|
|
tbl = vzalloc(size);
|
|
|
|
if (tbl == NULL)
|
|
return NULL;
|
|
|
|
tbl->size = nbuckets;
|
|
|
|
return tbl;
|
|
}
|
|
|
|
static void bucket_table_free(const struct bucket_table *tbl)
|
|
{
|
|
kvfree(tbl);
|
|
}
|
|
|
|
/**
|
|
* rht_grow_above_75 - returns true if nelems > 0.75 * table-size
|
|
* @ht: hash table
|
|
* @new_size: new table size
|
|
*/
|
|
bool rht_grow_above_75(const struct rhashtable *ht, size_t new_size)
|
|
{
|
|
/* Expand table when exceeding 75% load */
|
|
return ht->nelems > (new_size / 4 * 3);
|
|
}
|
|
EXPORT_SYMBOL_GPL(rht_grow_above_75);
|
|
|
|
/**
|
|
* rht_shrink_below_30 - returns true if nelems < 0.3 * table-size
|
|
* @ht: hash table
|
|
* @new_size: new table size
|
|
*/
|
|
bool rht_shrink_below_30(const struct rhashtable *ht, size_t new_size)
|
|
{
|
|
/* Shrink table beneath 30% load */
|
|
return ht->nelems < (new_size * 3 / 10);
|
|
}
|
|
EXPORT_SYMBOL_GPL(rht_shrink_below_30);
|
|
|
|
static void hashtable_chain_unzip(const struct rhashtable *ht,
|
|
const struct bucket_table *new_tbl,
|
|
struct bucket_table *old_tbl, size_t n)
|
|
{
|
|
struct rhash_head *he, *p, *next;
|
|
unsigned int h;
|
|
|
|
/* Old bucket empty, no work needed. */
|
|
p = rht_dereference(old_tbl->buckets[n], ht);
|
|
if (!p)
|
|
return;
|
|
|
|
/* Advance the old bucket pointer one or more times until it
|
|
* reaches a node that doesn't hash to the same bucket as the
|
|
* previous node p. Call the previous node p;
|
|
*/
|
|
h = head_hashfn(ht, p, new_tbl->size);
|
|
rht_for_each(he, p->next, ht) {
|
|
if (head_hashfn(ht, he, new_tbl->size) != h)
|
|
break;
|
|
p = he;
|
|
}
|
|
RCU_INIT_POINTER(old_tbl->buckets[n], p->next);
|
|
|
|
/* Find the subsequent node which does hash to the same
|
|
* bucket as node P, or NULL if no such node exists.
|
|
*/
|
|
next = NULL;
|
|
if (he) {
|
|
rht_for_each(he, he->next, ht) {
|
|
if (head_hashfn(ht, he, new_tbl->size) == h) {
|
|
next = he;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Set p's next pointer to that subsequent node pointer,
|
|
* bypassing the nodes which do not hash to p's bucket
|
|
*/
|
|
RCU_INIT_POINTER(p->next, next);
|
|
}
|
|
|
|
/**
|
|
* rhashtable_expand - Expand hash table while allowing concurrent lookups
|
|
* @ht: the hash table to expand
|
|
* @flags: allocation flags
|
|
*
|
|
* A secondary bucket array is allocated and the hash entries are migrated
|
|
* while keeping them on both lists until the end of the RCU grace period.
|
|
*
|
|
* This function may only be called in a context where it is safe to call
|
|
* synchronize_rcu(), e.g. not within a rcu_read_lock() section.
|
|
*
|
|
* The caller must ensure that no concurrent table mutations take place.
|
|
* It is however valid to have concurrent lookups if they are RCU protected.
|
|
*/
|
|
int rhashtable_expand(struct rhashtable *ht, gfp_t flags)
|
|
{
|
|
struct bucket_table *new_tbl, *old_tbl = rht_dereference(ht->tbl, ht);
|
|
struct rhash_head *he;
|
|
unsigned int i, h;
|
|
bool complete;
|
|
|
|
ASSERT_RHT_MUTEX(ht);
|
|
|
|
if (ht->p.max_shift && ht->shift >= ht->p.max_shift)
|
|
return 0;
|
|
|
|
new_tbl = bucket_table_alloc(old_tbl->size * 2, flags);
|
|
if (new_tbl == NULL)
|
|
return -ENOMEM;
|
|
|
|
ht->shift++;
|
|
|
|
/* For each new bucket, search the corresponding old bucket
|
|
* for the first entry that hashes to the new bucket, and
|
|
* link the new bucket to that entry. Since all the entries
|
|
* which will end up in the new bucket appear in the same
|
|
* old bucket, this constructs an entirely valid new hash
|
|
* table, but with multiple buckets "zipped" together into a
|
|
* single imprecise chain.
|
|
*/
|
|
for (i = 0; i < new_tbl->size; i++) {
|
|
h = i & (old_tbl->size - 1);
|
|
rht_for_each(he, old_tbl->buckets[h], ht) {
|
|
if (head_hashfn(ht, he, new_tbl->size) == i) {
|
|
RCU_INIT_POINTER(new_tbl->buckets[i], he);
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Publish the new table pointer. Lookups may now traverse
|
|
* the new table, but they will not benefit from any
|
|
* additional efficiency until later steps unzip the buckets.
|
|
*/
|
|
rcu_assign_pointer(ht->tbl, new_tbl);
|
|
|
|
/* Unzip interleaved hash chains */
|
|
do {
|
|
/* Wait for readers. All new readers will see the new
|
|
* table, and thus no references to the old table will
|
|
* remain.
|
|
*/
|
|
synchronize_rcu();
|
|
|
|
/* For each bucket in the old table (each of which
|
|
* contains items from multiple buckets of the new
|
|
* table): ...
|
|
*/
|
|
complete = true;
|
|
for (i = 0; i < old_tbl->size; i++) {
|
|
hashtable_chain_unzip(ht, new_tbl, old_tbl, i);
|
|
if (old_tbl->buckets[i] != NULL)
|
|
complete = false;
|
|
}
|
|
} while (!complete);
|
|
|
|
bucket_table_free(old_tbl);
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(rhashtable_expand);
|
|
|
|
/**
|
|
* rhashtable_shrink - Shrink hash table while allowing concurrent lookups
|
|
* @ht: the hash table to shrink
|
|
* @flags: allocation flags
|
|
*
|
|
* This function may only be called in a context where it is safe to call
|
|
* synchronize_rcu(), e.g. not within a rcu_read_lock() section.
|
|
*
|
|
* The caller must ensure that no concurrent table mutations take place.
|
|
* It is however valid to have concurrent lookups if they are RCU protected.
|
|
*/
|
|
int rhashtable_shrink(struct rhashtable *ht, gfp_t flags)
|
|
{
|
|
struct bucket_table *ntbl, *tbl = rht_dereference(ht->tbl, ht);
|
|
struct rhash_head __rcu **pprev;
|
|
unsigned int i;
|
|
|
|
ASSERT_RHT_MUTEX(ht);
|
|
|
|
if (ht->shift <= ht->p.min_shift)
|
|
return 0;
|
|
|
|
ntbl = bucket_table_alloc(tbl->size / 2, flags);
|
|
if (ntbl == NULL)
|
|
return -ENOMEM;
|
|
|
|
ht->shift--;
|
|
|
|
/* Link each bucket in the new table to the first bucket
|
|
* in the old table that contains entries which will hash
|
|
* to the new bucket.
|
|
*/
|
|
for (i = 0; i < ntbl->size; i++) {
|
|
ntbl->buckets[i] = tbl->buckets[i];
|
|
|
|
/* Link each bucket in the new table to the first bucket
|
|
* in the old table that contains entries which will hash
|
|
* to the new bucket.
|
|
*/
|
|
for (pprev = &ntbl->buckets[i]; *pprev != NULL;
|
|
pprev = &rht_dereference(*pprev, ht)->next)
|
|
;
|
|
RCU_INIT_POINTER(*pprev, tbl->buckets[i + ntbl->size]);
|
|
}
|
|
|
|
/* Publish the new, valid hash table */
|
|
rcu_assign_pointer(ht->tbl, ntbl);
|
|
|
|
/* Wait for readers. No new readers will have references to the
|
|
* old hash table.
|
|
*/
|
|
synchronize_rcu();
|
|
|
|
bucket_table_free(tbl);
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(rhashtable_shrink);
|
|
|
|
/**
|
|
* rhashtable_insert - insert object into hash hash table
|
|
* @ht: hash table
|
|
* @obj: pointer to hash head inside object
|
|
* @flags: allocation flags (table expansion)
|
|
*
|
|
* Will automatically grow the table via rhashtable_expand() if the the
|
|
* grow_decision function specified at rhashtable_init() returns true.
|
|
*
|
|
* The caller must ensure that no concurrent table mutations occur. It is
|
|
* however valid to have concurrent lookups if they are RCU protected.
|
|
*/
|
|
void rhashtable_insert(struct rhashtable *ht, struct rhash_head *obj,
|
|
gfp_t flags)
|
|
{
|
|
struct bucket_table *tbl = rht_dereference(ht->tbl, ht);
|
|
u32 hash;
|
|
|
|
ASSERT_RHT_MUTEX(ht);
|
|
|
|
hash = head_hashfn(ht, obj, tbl->size);
|
|
RCU_INIT_POINTER(obj->next, tbl->buckets[hash]);
|
|
rcu_assign_pointer(tbl->buckets[hash], obj);
|
|
ht->nelems++;
|
|
|
|
if (ht->p.grow_decision && ht->p.grow_decision(ht, tbl->size))
|
|
rhashtable_expand(ht, flags);
|
|
}
|
|
EXPORT_SYMBOL_GPL(rhashtable_insert);
|
|
|
|
/**
|
|
* rhashtable_remove_pprev - remove object from hash table given previous element
|
|
* @ht: hash table
|
|
* @obj: pointer to hash head inside object
|
|
* @pprev: pointer to previous element
|
|
* @flags: allocation flags (table expansion)
|
|
*
|
|
* Identical to rhashtable_remove() but caller is alreayd aware of the element
|
|
* in front of the element to be deleted. This is in particular useful for
|
|
* deletion when combined with walking or lookup.
|
|
*/
|
|
void rhashtable_remove_pprev(struct rhashtable *ht, struct rhash_head *obj,
|
|
struct rhash_head __rcu **pprev, gfp_t flags)
|
|
{
|
|
struct bucket_table *tbl = rht_dereference(ht->tbl, ht);
|
|
|
|
ASSERT_RHT_MUTEX(ht);
|
|
|
|
RCU_INIT_POINTER(*pprev, obj->next);
|
|
ht->nelems--;
|
|
|
|
if (ht->p.shrink_decision &&
|
|
ht->p.shrink_decision(ht, tbl->size))
|
|
rhashtable_shrink(ht, flags);
|
|
}
|
|
EXPORT_SYMBOL_GPL(rhashtable_remove_pprev);
|
|
|
|
/**
|
|
* rhashtable_remove - remove object from hash table
|
|
* @ht: hash table
|
|
* @obj: pointer to hash head inside object
|
|
* @flags: allocation flags (table expansion)
|
|
*
|
|
* Since the hash chain is single linked, the removal operation needs to
|
|
* walk the bucket chain upon removal. The removal operation is thus
|
|
* considerable slow if the hash table is not correctly sized.
|
|
*
|
|
* Will automatically shrink the table via rhashtable_expand() if the the
|
|
* shrink_decision function specified at rhashtable_init() returns true.
|
|
*
|
|
* The caller must ensure that no concurrent table mutations occur. It is
|
|
* however valid to have concurrent lookups if they are RCU protected.
|
|
*/
|
|
bool rhashtable_remove(struct rhashtable *ht, struct rhash_head *obj,
|
|
gfp_t flags)
|
|
{
|
|
struct bucket_table *tbl = rht_dereference(ht->tbl, ht);
|
|
struct rhash_head __rcu **pprev;
|
|
struct rhash_head *he;
|
|
u32 h;
|
|
|
|
ASSERT_RHT_MUTEX(ht);
|
|
|
|
h = head_hashfn(ht, obj, tbl->size);
|
|
|
|
pprev = &tbl->buckets[h];
|
|
rht_for_each(he, tbl->buckets[h], ht) {
|
|
if (he != obj) {
|
|
pprev = &he->next;
|
|
continue;
|
|
}
|
|
|
|
rhashtable_remove_pprev(ht, he, pprev, flags);
|
|
return true;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
EXPORT_SYMBOL_GPL(rhashtable_remove);
|
|
|
|
/**
|
|
* rhashtable_lookup - lookup key in hash table
|
|
* @ht: hash table
|
|
* @key: pointer to key
|
|
*
|
|
* Computes the hash value for the key and traverses the bucket chain looking
|
|
* for a entry with an identical key. The first matching entry is returned.
|
|
*
|
|
* This lookup function may only be used for fixed key hash table (key_len
|
|
* paramter set). It will BUG() if used inappropriately.
|
|
*
|
|
* Lookups may occur in parallel with hash mutations as long as the lookup is
|
|
* guarded by rcu_read_lock(). The caller must take care of this.
|
|
*/
|
|
void *rhashtable_lookup(const struct rhashtable *ht, const void *key)
|
|
{
|
|
const struct bucket_table *tbl = rht_dereference_rcu(ht->tbl, ht);
|
|
struct rhash_head *he;
|
|
u32 h;
|
|
|
|
BUG_ON(!ht->p.key_len);
|
|
|
|
h = __hashfn(ht, key, ht->p.key_len, tbl->size);
|
|
rht_for_each_rcu(he, tbl->buckets[h], ht) {
|
|
if (memcmp(rht_obj(ht, he) + ht->p.key_offset, key,
|
|
ht->p.key_len))
|
|
continue;
|
|
return (void *) he - ht->p.head_offset;
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
EXPORT_SYMBOL_GPL(rhashtable_lookup);
|
|
|
|
/**
|
|
* rhashtable_lookup_compare - search hash table with compare function
|
|
* @ht: hash table
|
|
* @key: pointer to key
|
|
* @compare: compare function, must return true on match
|
|
* @arg: argument passed on to compare function
|
|
*
|
|
* Traverses the bucket chain behind the provided hash value and calls the
|
|
* specified compare function for each entry.
|
|
*
|
|
* Lookups may occur in parallel with hash mutations as long as the lookup is
|
|
* guarded by rcu_read_lock(). The caller must take care of this.
|
|
*
|
|
* Returns the first entry on which the compare function returned true.
|
|
*/
|
|
void *rhashtable_lookup_compare(const struct rhashtable *ht, void *key,
|
|
bool (*compare)(void *, void *), void *arg)
|
|
{
|
|
const struct bucket_table *tbl = rht_dereference_rcu(ht->tbl, ht);
|
|
struct rhash_head *he;
|
|
u32 hash;
|
|
|
|
hash = __hashfn(ht, key, ht->p.key_len, tbl->size);
|
|
|
|
rht_for_each_rcu(he, tbl->buckets[hash], ht) {
|
|
if (!compare(rht_obj(ht, he), arg))
|
|
continue;
|
|
return (void *) he - ht->p.head_offset;
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
EXPORT_SYMBOL_GPL(rhashtable_lookup_compare);
|
|
|
|
static size_t rounded_hashtable_size(struct rhashtable_params *params)
|
|
{
|
|
return max(roundup_pow_of_two(params->nelem_hint * 4 / 3),
|
|
1UL << params->min_shift);
|
|
}
|
|
|
|
/**
|
|
* rhashtable_init - initialize a new hash table
|
|
* @ht: hash table to be initialized
|
|
* @params: configuration parameters
|
|
*
|
|
* Initializes a new hash table based on the provided configuration
|
|
* parameters. A table can be configured either with a variable or
|
|
* fixed length key:
|
|
*
|
|
* Configuration Example 1: Fixed length keys
|
|
* struct test_obj {
|
|
* int key;
|
|
* void * my_member;
|
|
* struct rhash_head node;
|
|
* };
|
|
*
|
|
* struct rhashtable_params params = {
|
|
* .head_offset = offsetof(struct test_obj, node),
|
|
* .key_offset = offsetof(struct test_obj, key),
|
|
* .key_len = sizeof(int),
|
|
* .hashfn = arch_fast_hash,
|
|
* .mutex_is_held = &my_mutex_is_held,
|
|
* };
|
|
*
|
|
* Configuration Example 2: Variable length keys
|
|
* struct test_obj {
|
|
* [...]
|
|
* struct rhash_head node;
|
|
* };
|
|
*
|
|
* u32 my_hash_fn(const void *data, u32 seed)
|
|
* {
|
|
* struct test_obj *obj = data;
|
|
*
|
|
* return [... hash ...];
|
|
* }
|
|
*
|
|
* struct rhashtable_params params = {
|
|
* .head_offset = offsetof(struct test_obj, node),
|
|
* .hashfn = arch_fast_hash,
|
|
* .obj_hashfn = my_hash_fn,
|
|
* .mutex_is_held = &my_mutex_is_held,
|
|
* };
|
|
*/
|
|
int rhashtable_init(struct rhashtable *ht, struct rhashtable_params *params)
|
|
{
|
|
struct bucket_table *tbl;
|
|
size_t size;
|
|
|
|
size = HASH_DEFAULT_SIZE;
|
|
|
|
if ((params->key_len && !params->hashfn) ||
|
|
(!params->key_len && !params->obj_hashfn))
|
|
return -EINVAL;
|
|
|
|
params->min_shift = max_t(size_t, params->min_shift,
|
|
ilog2(HASH_MIN_SIZE));
|
|
|
|
if (params->nelem_hint)
|
|
size = rounded_hashtable_size(params);
|
|
|
|
tbl = bucket_table_alloc(size, GFP_KERNEL);
|
|
if (tbl == NULL)
|
|
return -ENOMEM;
|
|
|
|
memset(ht, 0, sizeof(*ht));
|
|
ht->shift = ilog2(tbl->size);
|
|
memcpy(&ht->p, params, sizeof(*params));
|
|
RCU_INIT_POINTER(ht->tbl, tbl);
|
|
|
|
if (!ht->p.hash_rnd)
|
|
get_random_bytes(&ht->p.hash_rnd, sizeof(ht->p.hash_rnd));
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(rhashtable_init);
|
|
|
|
/**
|
|
* rhashtable_destroy - destroy hash table
|
|
* @ht: the hash table to destroy
|
|
*
|
|
* Frees the bucket array. This function is not rcu safe, therefore the caller
|
|
* has to make sure that no resizing may happen by unpublishing the hashtable
|
|
* and waiting for the quiescent cycle before releasing the bucket array.
|
|
*/
|
|
void rhashtable_destroy(const struct rhashtable *ht)
|
|
{
|
|
bucket_table_free(ht->tbl);
|
|
}
|
|
EXPORT_SYMBOL_GPL(rhashtable_destroy);
|
|
|
|
/**************************************************************************
|
|
* Self Test
|
|
**************************************************************************/
|
|
|
|
#ifdef CONFIG_TEST_RHASHTABLE
|
|
|
|
#define TEST_HT_SIZE 8
|
|
#define TEST_ENTRIES 2048
|
|
#define TEST_PTR ((void *) 0xdeadbeef)
|
|
#define TEST_NEXPANDS 4
|
|
|
|
static int test_mutex_is_held(void)
|
|
{
|
|
return 1;
|
|
}
|
|
|
|
struct test_obj {
|
|
void *ptr;
|
|
int value;
|
|
struct rhash_head node;
|
|
};
|
|
|
|
static int __init test_rht_lookup(struct rhashtable *ht)
|
|
{
|
|
unsigned int i;
|
|
|
|
for (i = 0; i < TEST_ENTRIES * 2; i++) {
|
|
struct test_obj *obj;
|
|
bool expected = !(i % 2);
|
|
u32 key = i;
|
|
|
|
obj = rhashtable_lookup(ht, &key);
|
|
|
|
if (expected && !obj) {
|
|
pr_warn("Test failed: Could not find key %u\n", key);
|
|
return -ENOENT;
|
|
} else if (!expected && obj) {
|
|
pr_warn("Test failed: Unexpected entry found for key %u\n",
|
|
key);
|
|
return -EEXIST;
|
|
} else if (expected && obj) {
|
|
if (obj->ptr != TEST_PTR || obj->value != i) {
|
|
pr_warn("Test failed: Lookup value mismatch %p!=%p, %u!=%u\n",
|
|
obj->ptr, TEST_PTR, obj->value, i);
|
|
return -EINVAL;
|
|
}
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void test_bucket_stats(struct rhashtable *ht,
|
|
struct bucket_table *tbl,
|
|
bool quiet)
|
|
{
|
|
unsigned int cnt, i, total = 0;
|
|
struct test_obj *obj;
|
|
|
|
for (i = 0; i < tbl->size; i++) {
|
|
cnt = 0;
|
|
|
|
if (!quiet)
|
|
pr_info(" [%#4x/%zu]", i, tbl->size);
|
|
|
|
rht_for_each_entry_rcu(obj, tbl->buckets[i], node) {
|
|
cnt++;
|
|
total++;
|
|
if (!quiet)
|
|
pr_cont(" [%p],", obj);
|
|
}
|
|
|
|
if (!quiet)
|
|
pr_cont("\n [%#x] first element: %p, chain length: %u\n",
|
|
i, tbl->buckets[i], cnt);
|
|
}
|
|
|
|
pr_info(" Traversal complete: counted=%u, nelems=%zu, entries=%d\n",
|
|
total, ht->nelems, TEST_ENTRIES);
|
|
}
|
|
|
|
static int __init test_rhashtable(struct rhashtable *ht)
|
|
{
|
|
struct bucket_table *tbl;
|
|
struct test_obj *obj, *next;
|
|
int err;
|
|
unsigned int i;
|
|
|
|
/*
|
|
* Insertion Test:
|
|
* Insert TEST_ENTRIES into table with all keys even numbers
|
|
*/
|
|
pr_info(" Adding %d keys\n", TEST_ENTRIES);
|
|
for (i = 0; i < TEST_ENTRIES; i++) {
|
|
struct test_obj *obj;
|
|
|
|
obj = kzalloc(sizeof(*obj), GFP_KERNEL);
|
|
if (!obj) {
|
|
err = -ENOMEM;
|
|
goto error;
|
|
}
|
|
|
|
obj->ptr = TEST_PTR;
|
|
obj->value = i * 2;
|
|
|
|
rhashtable_insert(ht, &obj->node, GFP_KERNEL);
|
|
}
|
|
|
|
rcu_read_lock();
|
|
tbl = rht_dereference_rcu(ht->tbl, ht);
|
|
test_bucket_stats(ht, tbl, true);
|
|
test_rht_lookup(ht);
|
|
rcu_read_unlock();
|
|
|
|
for (i = 0; i < TEST_NEXPANDS; i++) {
|
|
pr_info(" Table expansion iteration %u...\n", i);
|
|
rhashtable_expand(ht, GFP_KERNEL);
|
|
|
|
rcu_read_lock();
|
|
pr_info(" Verifying lookups...\n");
|
|
test_rht_lookup(ht);
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
for (i = 0; i < TEST_NEXPANDS; i++) {
|
|
pr_info(" Table shrinkage iteration %u...\n", i);
|
|
rhashtable_shrink(ht, GFP_KERNEL);
|
|
|
|
rcu_read_lock();
|
|
pr_info(" Verifying lookups...\n");
|
|
test_rht_lookup(ht);
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
pr_info(" Deleting %d keys\n", TEST_ENTRIES);
|
|
for (i = 0; i < TEST_ENTRIES; i++) {
|
|
u32 key = i * 2;
|
|
|
|
obj = rhashtable_lookup(ht, &key);
|
|
BUG_ON(!obj);
|
|
|
|
rhashtable_remove(ht, &obj->node, GFP_KERNEL);
|
|
kfree(obj);
|
|
}
|
|
|
|
return 0;
|
|
|
|
error:
|
|
tbl = rht_dereference_rcu(ht->tbl, ht);
|
|
for (i = 0; i < tbl->size; i++)
|
|
rht_for_each_entry_safe(obj, next, tbl->buckets[i], ht, node)
|
|
kfree(obj);
|
|
|
|
return err;
|
|
}
|
|
|
|
static int __init test_rht_init(void)
|
|
{
|
|
struct rhashtable ht;
|
|
struct rhashtable_params params = {
|
|
.nelem_hint = TEST_HT_SIZE,
|
|
.head_offset = offsetof(struct test_obj, node),
|
|
.key_offset = offsetof(struct test_obj, value),
|
|
.key_len = sizeof(int),
|
|
.hashfn = arch_fast_hash,
|
|
.mutex_is_held = &test_mutex_is_held,
|
|
.grow_decision = rht_grow_above_75,
|
|
.shrink_decision = rht_shrink_below_30,
|
|
};
|
|
int err;
|
|
|
|
pr_info("Running resizable hashtable tests...\n");
|
|
|
|
err = rhashtable_init(&ht, ¶ms);
|
|
if (err < 0) {
|
|
pr_warn("Test failed: Unable to initialize hashtable: %d\n",
|
|
err);
|
|
return err;
|
|
}
|
|
|
|
err = test_rhashtable(&ht);
|
|
|
|
rhashtable_destroy(&ht);
|
|
|
|
return err;
|
|
}
|
|
|
|
subsys_initcall(test_rht_init);
|
|
|
|
#endif /* CONFIG_TEST_RHASHTABLE */
|