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Slabbed hash table. Drops contention on hash table main lock.

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git-svn-id: file:///svn/unbound/trunk@194 be551aaa-1e26-0410-a405-d3ace91eadb9
This commit is contained in:
Wouter Wijngaards 2007-03-23 15:17:11 +00:00
parent 2092d6535a
commit f559c3c2ca
11 changed files with 711 additions and 12 deletions
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1
doc/Changelog
View File

@ -3,6 +3,7 @@
- covered up memory leak of the entry locks.
- answers from the cache correctly. Copies flags correctly.
- sanity check for incoming query replies.
- slabbed hash table. Much nicer contention, need dual cpu to see.
22 March 2007: Wouter
- AIX configure check.

10
testcode/checklocks.c
View File

@ -51,6 +51,11 @@
*/
#ifdef USE_THREAD_DEBUG
/** How long to wait before lock attempt is a failure. */
#define CHECK_LOCK_TIMEOUT 15 /* seconds */
/** How long to wait before join attempt is a failure. */
#define CHECK_JOIN_TIMEOUT 120 /* seconds */
/** if key has been created */
static int key_created = 0;
/** we hide the thread debug info with this key. */
@ -326,10 +331,11 @@ checklock_destroy(enum check_lock_type type, struct checked_lock** lock,
/* contention, look at fraction in trouble. */
if(e->history_count > 1 &&
1000*e->contention_count/e->history_count > contention_interest) {
log_info("lock created %s %s %d has contention %u of %u",
log_info("lock created %s %s %d has contention %u of %u (%d%%)",
e->create_func, e->create_file, e->create_line,
(unsigned int)e->contention_count,
(unsigned int)e->history_count);
(unsigned int)e->history_count,
100*e->contention_count/e->history_count);
}
/* delete it */

4
testcode/checklocks.h
View File

@ -71,10 +71,6 @@
/******************* THREAD DEBUG ************************/
#include <pthread.h>
/** How long to wait before lock attempt is a failure. */
#define CHECK_LOCK_TIMEOUT 5 /* seconds */
/** How long to wait before join attempt is a failure. */
#define CHECK_JOIN_TIMEOUT 120 /* seconds */
/** How many threads to allocate for */
#define THRDEBUG_MAX_THREADS 32 /* threads */
/** do we check locking order */

7
testcode/unitlruhash.c
View File

@ -72,6 +72,7 @@ static hashvalue_t myhash(int id) {return (hashvalue_t)id & 0x0f;}
/** allocate new key, fill in hash. */
static struct testkey* newkey(int id) {
struct testkey* k = (struct testkey*)calloc(1, sizeof(struct testkey));
if(!k) fatal_exit("out of memory");
k->id = id;
k->entry.hash = myhash(id);
k->entry.key = k;
@ -82,6 +83,7 @@ static struct testkey* newkey(int id) {
static struct testdata* newdata(int val) {
struct testdata* d = (struct testdata*)calloc(1,
sizeof(struct testdata));
if(!d) fatal_exit("out of memory");
d->data = val;
return d;
}
@ -102,6 +104,7 @@ test_bin_find_entry(struct lruhash* table)
struct testkey* k4 = newkey(12 + 1024*2);
hashvalue_t h = myhash(12);
struct lruhash_bin bin;
memset(&bin, 0, sizeof(bin));
bin_init(&bin, 1);
/* remove from empty list */
@ -488,7 +491,9 @@ void lruhash_test()
{
/* start very very small array, so it can do lots of table_grow() */
/* also small in size so that reclaim has to be done quickly. */
struct lruhash* table = lruhash_create(2, 4096,
struct lruhash* table ;
printf("lruhash test\n");
table = lruhash_create(2, 4096,
test_sizefunc, test_compfunc, test_delkey, test_deldata, NULL);
test_bin_find_entry(table);
test_lru(table);

3
testcode/unitmain.c
View File

@ -111,7 +111,7 @@ dname_to_buf(ldns_buffer* b, const char* str)
if(status != LDNS_STATUS_OK)
fatal_exit("%s ldns: %s", __func__,
ldns_get_errorstr_by_id(status));
ldns_rdf_free(rdf);
ldns_rdf_deep_free(rdf);
ldns_buffer_flip(b);
return b;
}
@ -150,6 +150,7 @@ main(int argc, char* argv[])
alloc_test();
msgreply_test();
lruhash_test();
slabhash_test();
checklock_stop();
printf("%d tests succeeded\n", testcount);
return 0;

2
testcode/unitmain.h
View File

@ -49,5 +49,7 @@ extern int testcount;
/** unit test lruhashtable implementation */
void lruhash_test();
/** unit test slabhashtable implementation */
void slabhash_test();
#endif /* TESTCODE_UNITMAIN_H */

415
testcode/unitslabhash.c Normal file
View File

@ -0,0 +1,415 @@
/*
* testcode/unitslabhash.c - unit test for slabhash table.
*
* Copyright (c) 2007, NLnet Labs. All rights reserved.
*
* This software is open source.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* Neither the name of the NLNET LABS nor the names of its contributors may
* be used to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
*/
/**
* \file
* Tests the locking LRU keeping hash table implementation.
*/
#include "config.h"
#include "testcode/unitmain.h"
#include "util/log.h"
#include "util/storage/slabhash.h"
/* --- test representation --- */
/** structure contains test key */
struct slabtestkey {
/** the key id */
int id;
/** the entry */
struct lruhash_entry entry;
};
/** structure contains test data */
struct slabtestdata {
/** data value */
int data;
};
/** sizefunc for lruhash */
static size_t test_sizefunc(void*, void*);
/** comparefunc for lruhash */
static int test_compfunc(void*, void*);
/** delkey for lruhash */
static void test_delkey(void*, void*);
/** deldata for lruhash */
static void test_deldata(void*, void*);
/* --- end test representation --- */
/** hash func, very bad to improve collisions, both high and low bits. */
static hashvalue_t myhash(int id) {
hashvalue_t h = (hashvalue_t)id & 0x0f;
h |= (h << 28);
return h;
}
/** allocate new key, fill in hash. */
static struct slabtestkey* newkey(int id) {
struct slabtestkey* k = (struct slabtestkey*)calloc(1, sizeof(struct slabtestkey));
if(!k) fatal_exit("out of memory");
k->id = id;
k->entry.hash = myhash(id);
k->entry.key = k;
lock_rw_init(&k->entry.lock);
return k;
}
/** new data el */
static struct slabtestdata* newdata(int val) {
struct slabtestdata* d = (struct slabtestdata*)calloc(1,
sizeof(struct slabtestdata));
if(!d) fatal_exit("out of memory");
d->data = val;
return d;
}
/** delete key */
static void delkey(struct slabtestkey* k) {
lock_rw_destroy(&k->entry.lock); free(k);}
/** delete data */
static void deldata(struct slabtestdata* d) {free(d);}
/** test hashtable using short sequence */
static void
test_short_table(struct slabhash* table)
{
struct slabtestkey* k = newkey(12);
struct slabtestkey* k2 = newkey(14);
struct slabtestdata* d = newdata(128);
struct slabtestdata* d2 = newdata(129);
k->entry.data = d;
k2->entry.data = d2;
slabhash_insert(table, myhash(12), &k->entry, d);
slabhash_insert(table, myhash(14), &k2->entry, d2);
unit_assert( slabhash_lookup(table, myhash(12), k, 0) == &k->entry);
lock_rw_unlock( &k->entry.lock );
unit_assert( slabhash_lookup(table, myhash(14), k2, 0) == &k2->entry);
lock_rw_unlock( &k2->entry.lock );
slabhash_remove(table, myhash(12), k);
slabhash_remove(table, myhash(14), k2);
}
/** number of hash test max */
#define HASHTESTMAX 100
/** test adding a random element */
static void
testadd(struct slabhash* table, struct slabtestdata* ref[])
{
int numtoadd = random() % HASHTESTMAX;
struct slabtestdata* data = newdata(numtoadd);
struct slabtestkey* key = newkey(numtoadd);
key->entry.data = data;
slabhash_insert(table, myhash(numtoadd), &key->entry, data);
ref[numtoadd] = data;
}
/** test adding a random element */
static void
testremove(struct slabhash* table, struct slabtestdata* ref[])
{
int num = random() % HASHTESTMAX;
struct slabtestkey* key = newkey(num);
slabhash_remove(table, myhash(num), key);
ref[num] = NULL;
delkey(key);
}
/** test adding a random element */
static void
testlookup(struct slabhash* table, struct slabtestdata* ref[])
{
int num = random() % HASHTESTMAX;
struct slabtestkey* key = newkey(num);
struct lruhash_entry* en = slabhash_lookup(table, myhash(num), key, 0);
struct slabtestdata* data = en? (struct slabtestdata*)en->data : NULL;
if(en) {
unit_assert(en->key);
unit_assert(en->data);
}
if(0) log_info("lookup %d got %d, expect %d", num, en? data->data :-1,
ref[num]? ref[num]->data : -1);
unit_assert( data == ref[num] );
if(en) lock_rw_unlock(&en->lock);
delkey(key);
}
/** check integrity of hash table */
static void
check_lru_table(struct lruhash* table)
{
struct lruhash_entry* p;
size_t c = 0;
lock_quick_lock(&table->lock);
unit_assert( table->num <= table->size);
unit_assert( table->size_mask == (int)table->size-1 );
unit_assert( (table->lru_start && table->lru_end) ||
(!table->lru_start && !table->lru_end) );
unit_assert( table->space_used <= table->space_max );
/* check lru list integrity */
if(table->lru_start)
unit_assert(table->lru_start->lru_prev == NULL);
if(table->lru_end)
unit_assert(table->lru_end->lru_next == NULL);
p = table->lru_start;
while(p) {
if(p->lru_prev) {
unit_assert(p->lru_prev->lru_next == p);
}
if(p->lru_next) {
unit_assert(p->lru_next->lru_prev == p);
}
c++;
p = p->lru_next;
}
unit_assert(c == table->num);
/* this assertion is specific to the unit test */
unit_assert( table->space_used ==
table->num * test_sizefunc(NULL, NULL) );
lock_quick_unlock(&table->lock);
}
/** check integrity of hash table */
static void
check_table(struct slabhash* table)
{
size_t i;
for(i=0; i<table->size; i++)
check_lru_table(table->array[i]);
}
/** test adding a random element (unlimited range) */
static void
testadd_unlim(struct slabhash* table, struct slabtestdata** ref)
{
int numtoadd = random() % (HASHTESTMAX * 10);
struct slabtestdata* data = newdata(numtoadd);
struct slabtestkey* key = newkey(numtoadd);
key->entry.data = data;
slabhash_insert(table, myhash(numtoadd), &key->entry, data);
if(ref)
ref[numtoadd] = data;
}
/** test adding a random element (unlimited range) */
static void
testremove_unlim(struct slabhash* table, struct slabtestdata** ref)
{
int num = random() % (HASHTESTMAX*10);
struct slabtestkey* key = newkey(num);
slabhash_remove(table, myhash(num), key);
if(ref)
ref[num] = NULL;
delkey(key);
}
/** test adding a random element (unlimited range) */
static void
testlookup_unlim(struct slabhash* table, struct slabtestdata** ref)
{
int num = random() % (HASHTESTMAX*10);
struct slabtestkey* key = newkey(num);
struct lruhash_entry* en = slabhash_lookup(table, myhash(num), key, 0);
struct slabtestdata* data = en? (struct slabtestdata*)en->data : NULL;
if(en) {
unit_assert(en->key);
unit_assert(en->data);
}
if(0 && ref) log_info("lookup unlim %d got %d, expect %d", num, en ?
data->data :-1, ref[num] ? ref[num]->data : -1);
if(data && ref) {
/* its okay for !data, it fell off the lru */
unit_assert( data == ref[num] );
}
if(en) lock_rw_unlock(&en->lock);
delkey(key);
}
/** test with long sequence of adds, removes and updates, and lookups */
static void
test_long_table(struct slabhash* table)
{
/* assuming it all fits in the hastable, this check will work */
struct slabtestdata* ref[HASHTESTMAX * 100];
size_t i;
memset(ref, 0, sizeof(ref));
/* test assumption */
if(0) slabhash_status(table, "unit test", 1);
srandom(48);
for(i=0; i<1000; i++) {
/* what to do? */
switch(random() % 4) {
case 0:
case 3:
testadd(table, ref);
break;
case 1:
testremove(table, ref);
break;
case 2:
testlookup(table, ref);
break;
default:
unit_assert(0);
}
if(0) slabhash_status(table, "unit test", 1);
check_table(table);
}
/* test more, but 'ref' assumption does not hold anymore */
for(i=0; i<1000; i++) {
/* what to do? */
switch(random() % 4) {
case 0:
case 3:
testadd_unlim(table, ref);
break;
case 1:
testremove_unlim(table, ref);
break;
case 2:
testlookup_unlim(table, ref);
break;
default:
unit_assert(0);
}
if(0) slabhash_status(table, "unlim", 1);
check_table(table);
}
}
/** structure to threaded test the lru hash table */
struct slab_test_thr {
/** thread num, first entry. */
int num;
/** id */
ub_thread_t id;
/** hash table */
struct slabhash* table;
};
/** main routine for threaded hash table test */
static void*
test_thr_main(void* arg)
{
struct slab_test_thr* t = (struct slab_test_thr*)arg;
int i;
log_thread_set(&t->num);
for(i=0; i<1000; i++) {
switch(random() % 4) {
case 0:
case 3:
testadd_unlim(t->table, NULL);
break;
case 1:
testremove_unlim(t->table, NULL);
break;
case 2:
testlookup_unlim(t->table, NULL);
break;
default:
unit_assert(0);
}
if(0) slabhash_status(t->table, "hashtest", 1);
if(i % 100 == 0) /* because of locking, not all the time */
check_table(t->table);
}
check_table(t->table);
return NULL;
}
/** test hash table access by multiple threads. */
static void
test_threaded_table(struct slabhash* table)
{
int numth = 10;
struct slab_test_thr t[100];
int i;
for(i=1; i<numth; i++) {
t[i].num = i;
t[i].table = table;
ub_thread_create(&t[i].id, test_thr_main, &t[i]);
}
for(i=1; i<numth; i++) {
ub_thread_join(t[i].id);
}
if(0) slabhash_status(table, "hashtest", 1);
}
void slabhash_test()
{
/* start very very small array, so it can do lots of table_grow() */
/* also small in size so that reclaim has to be done quickly. */
struct slabhash* table;
printf("slabhash test\n");
table = slabhash_create(4, 2, 4096,
test_sizefunc, test_compfunc, test_delkey, test_deldata, NULL);
test_short_table(table);
test_long_table(table);
slabhash_delete(table);
table = slabhash_create(4, 2, 4096,
test_sizefunc, test_compfunc, test_delkey, test_deldata, NULL);
test_threaded_table(table);
slabhash_delete(table);
}
static size_t test_sizefunc(void* ATTR_UNUSED(key), void* ATTR_UNUSED(data))
{
return sizeof(struct slabtestkey) + sizeof(struct slabtestdata);
}
static int test_compfunc(void* key1, void* key2)
{
struct slabtestkey* k1 = (struct slabtestkey*)key1;
struct slabtestkey* k2 = (struct slabtestkey*)key2;
if(k1->id == k2->id)
return 0;
if(k1->id > k2->id)
return 1;
return -1;
}
static void test_delkey(void* key, void* ATTR_UNUSED(arg))
{
delkey((struct slabtestkey*)key);
}
static void test_deldata(void* data, void* ATTR_UNUSED(arg))
{
deldata((struct slabtestdata*)data);
}

9
util/storage/lruhash.c
View File

@ -1,5 +1,5 @@
/*
* util/storage/lrulash.c - hashtable, hash function, LRU keeping.
* util/storage/lruhash.c - hashtable, hash function, LRU keeping.
*
* Copyright (c) 2007, NLnet Labs. All rights reserved.
*
@ -329,9 +329,10 @@ lruhash_insert(struct lruhash* table, hashvalue_t hash,
/* finish reclaim if any (outside of critical region) */
while(reclaimlist) {
struct lruhash_entry* n = reclaimlist->overflow_next;
void* d = reclaimlist->data;
lock_rw_unlock(&reclaimlist->lock);
(*table->delkeyfunc)(reclaimlist->key, table->cb_arg);
(*table->deldatafunc)(reclaimlist->data, table->cb_arg);
(*table->deldatafunc)(d, table->cb_arg);
reclaimlist = n;
}
}
@ -363,6 +364,7 @@ lruhash_remove(struct lruhash* table, hashvalue_t hash, void* key)
{
struct lruhash_entry* entry;
struct lruhash_bin* bin;
void *d;
lock_quick_lock(&table->lock);
bin = &table->array[hash & table->size_mask];
@ -382,8 +384,9 @@ lruhash_remove(struct lruhash* table, hashvalue_t hash, void* key)
lock_quick_unlock(&bin->lock);
/* finish removal */
lock_rw_unlock(&entry->lock);
d = entry->data;
(*table->delkeyfunc)(entry->key, table->cb_arg);
(*table->deldatafunc)(entry->data, table->cb_arg);
(*table->deldatafunc)(d, table->cb_arg);
}

2
util/storage/lruhash.h
View File

@ -1,5 +1,5 @@
/*
* util/storage/lrulash.h - hashtable, hash function, LRU keeping.
* util/storage/lruhash.h - hashtable, hash function, LRU keeping.
*
* Copyright (c) 2007, NLnet Labs. All rights reserved.
*

133
util/storage/slabhash.c Normal file
View File

@ -0,0 +1,133 @@
/*
* util/storage/slabhash.c - hashtable consisting of several smaller tables.
*
* Copyright (c) 2007, NLnet Labs. All rights reserved.
*
* This software is open source.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* Neither the name of the NLNET LABS nor the names of its contributors may
* be used to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/**
* \file
*
* Implementation of hash table that consists of smaller hash tables.
* It cannot grow, but that gives it the ability to have multiple
* locks. Also this means there are multiple LRU lists.
*/
#include "config.h"
#include "util/storage/slabhash.h"
struct slabhash* slabhash_create(size_t numtables, size_t start_size,
size_t maxmem, lruhash_sizefunc_t sizefunc,
lruhash_compfunc_t compfunc, lruhash_delkeyfunc_t delkeyfunc,
lruhash_deldatafunc_t deldatafunc, void* arg)
{
size_t i;
struct slabhash* sl = (struct slabhash*)calloc(1,
sizeof(struct slabhash));
if(!sl) return NULL;
sl->size = numtables;
log_assert(sl->size > 0);
sl->array = (struct lruhash**)calloc(sl->size, sizeof(struct lruhash*));
if(!sl->array) {
free(sl);
return NULL;
}
sl->mask = (uint32_t)(sl->size - 1);
if(sl->mask == 0) {
sl->shift = 0;
} else {
log_assert( (sl->size & sl->mask) == 0
/* size must be power of 2 */ );
sl->shift = 0;
while(!(sl->mask & 0x80000000)) {
sl->mask <<= 1;
sl->shift ++;
}
}
for(i=0; i<sl->size; i++) {
sl->array[i] = lruhash_create(start_size, maxmem / sl->size,
sizefunc, compfunc, delkeyfunc, deldatafunc, arg);
if(!sl->array[i]) {
slabhash_delete(sl);
return NULL;
}
}
return sl;
}
void slabhash_delete(struct slabhash* sl)
{
if(!sl)
return;
if(sl->array) {
size_t i;
for(i=0; i<sl->size; i++)
lruhash_delete(sl->array[i]);
free(sl->array);
}
free(sl);
}
/** helper routine to calculate the slabhash index */
static unsigned int
slab_idx(struct slabhash* sl, hashvalue_t hash)
{
return ((hash & sl->mask) >> sl->shift);
}
void slabhash_insert(struct slabhash* sl, hashvalue_t hash,
struct lruhash_entry* entry, void* data)
{
lruhash_insert(sl->array[slab_idx(sl, hash)], hash, entry, data);
}
struct lruhash_entry* slabhash_lookup(struct slabhash* sl,
hashvalue_t hash, void* key, int wr)
{
return lruhash_lookup(sl->array[slab_idx(sl, hash)], hash, key, wr);
}
void slabhash_remove(struct slabhash* sl, hashvalue_t hash, void* key)
{
lruhash_remove(sl->array[slab_idx(sl, hash)], hash, key);
}
void slabhash_status(struct slabhash* sl, const char* id, int extended)
{
size_t i;
char num[17];
log_info("Slabhash %s: %d tables mask=%x shift=%d",
id, sl->size, sl->mask, sl->shift);
for(i=0; i<sl->size; i++) {
snprintf(num, sizeof(num), "table %d", i);
lruhash_status(sl->array[i], num, extended);
}
}

137
util/storage/slabhash.h Normal file
View File

@ -0,0 +1,137 @@
/*
* util/storage/slabhash.h - hashtable consisting of several smaller tables.
*
* Copyright (c) 2007, NLnet Labs. All rights reserved.
*
* This software is open source.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* Neither the name of the NLNET LABS nor the names of its contributors may
* be used to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/**
* \file
*
* Hash table that consists of smaller hash tables.
* It cannot grow, but that gives it the ability to have multiple
* locks. Also this means there are multiple LRU lists.
*/
#ifndef UTIL_STORAGE_SLABHASH_H
#define UTIL_STORAGE_SLABHASH_H
#include "util/storage/lruhash.h"
/**
* Hash table formed from several smaller ones.
* None of the data inside the slabhash may be altered.
* Therefore, no locks are needed to access the structure.
*/
struct slabhash {
/** the size of the array - must be power of 2 */
size_t size;
/** size bitmask - uses high bits. */
uint32_t mask;
/** shift right this many bits to get index into array. */
unsigned int shift;
/** lookup array of hash tables */
struct lruhash** array;
};
/**
* Create new slabbed hash table.
* @param numtables: number of hash tables to use, other parameters used to
* initialize these smaller hashtables.
* @param start_size: size of hashtable array at start, must be power of 2.
* @param maxmem: maximum amount of memory this table is allowed to use.
* so every table gets maxmem/numtables to use for itself.
* @param sizefunc: calculates memory usage of entries.
* @param compfunc: compares entries, 0 on equality.
* @param delkeyfunc: deletes key.
* @param deldatafunc: deletes data.
* @param arg: user argument that is passed to user function calls.
* @return: new hash table or NULL on malloc failure.
*/
struct slabhash* slabhash_create(size_t numtables, size_t start_size,
size_t maxmem, lruhash_sizefunc_t sizefunc,
lruhash_compfunc_t compfunc, lruhash_delkeyfunc_t delkeyfunc,
lruhash_deldatafunc_t deldatafunc, void* arg);
/**
* Delete hash table. Entries are all deleted.
* @param table: to delete.
*/
void slabhash_delete(struct slabhash* table);
/**
* Insert a new element into the hashtable, uses lruhash_insert.
* If key is already present data pointer in that entry is updated.
*
* @param table: hash table.
* @param hash: hash value. User calculates the hash.
* @param entry: identifies the entry.
* If key already present, this entry->key is deleted immediately.
* But entry->data is set to NULL before deletion, and put into
* the existing entry. The data is then freed.
* @param data: the data.
*/
void slabhash_insert(struct slabhash* table, hashvalue_t hash,
struct lruhash_entry* entry, void* data);
/**
* Lookup an entry in the hashtable. Uses lruhash_lookup.
* At the end of the function you hold a (read/write)lock on the entry.
* The LRU is updated for the entry (if found).
* @param table: hash table.
* @param hash: hash of key.
* @param key: what to look for, compared against entries in overflow chain.
* the hash value must be set, and must work with compare function.
* @param wr: set to true if you desire a writelock on the entry.
* with a writelock you can update the data part.
* @return: pointer to the entry or NULL. The entry is locked.
* The user must unlock the entry when done.
*/
struct lruhash_entry* slabhash_lookup(struct slabhash* table,
hashvalue_t hash, void* key, int wr);
/**
* Remove entry from hashtable. Does nothing if not found in hashtable.
* Delfunc is called for the entry. Uses lruhash_remove.
* @param table: hash table.
* @param hash: hash of key.
* @param key: what to look for.
*/
void slabhash_remove(struct slabhash* table, hashvalue_t hash, void* key);
/**
* Output debug info to the log as to state of the hash table.
* @param table: hash table.
* @param id: string printed with table to identify the hash table.
* @param extended: set to true to print statistics on overflow bin lengths.
*/
void slabhash_status(struct slabhash* table, const char* id, int extended);
#endif /* UTIL_STORAGE_SLABHASH_H */