linux/lib/test_rhashtable.c

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/*
* Resizable, Scalable, Concurrent Hash Table
*
* Copyright (c) 2014-2015 Thomas Graf <tgraf@suug.ch>
* Copyright (c) 2008-2014 Patrick McHardy <kaber@trash.net>
*
* 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.
*/
/**************************************************************************
* Self Test
**************************************************************************/
#include <linux/init.h>
#include <linux/jhash.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/rcupdate.h>
#include <linux/rhashtable.h>
#include <linux/slab.h>
#define MAX_ENTRIES 1000000
#define TEST_INSERT_FAIL INT_MAX
static int entries = 50000;
module_param(entries, int, 0);
MODULE_PARM_DESC(entries, "Number of entries to add (default: 50000)");
static int runs = 4;
module_param(runs, int, 0);
MODULE_PARM_DESC(runs, "Number of test runs per variant (default: 4)");
static int max_size = 65536;
module_param(max_size, int, 0);
MODULE_PARM_DESC(runs, "Maximum table size (default: 65536)");
static bool shrinking = false;
module_param(shrinking, bool, 0);
MODULE_PARM_DESC(shrinking, "Enable automatic shrinking (default: off)");
static int size = 8;
module_param(size, int, 0);
MODULE_PARM_DESC(size, "Initial size hint of table (default: 8)");
struct test_obj {
int value;
struct rhash_head node;
};
static struct test_obj array[MAX_ENTRIES];
static struct rhashtable_params test_rht_params = {
.head_offset = offsetof(struct test_obj, node),
.key_offset = offsetof(struct test_obj, value),
.key_len = sizeof(int),
.hashfn = jhash,
.nulls_base = (3U << RHT_BASE_SHIFT),
};
static int __init test_rht_lookup(struct rhashtable *ht)
{
unsigned int i;
for (i = 0; i < entries * 2; i++) {
struct test_obj *obj;
bool expected = !(i % 2);
u32 key = i;
if (array[i / 2].value == TEST_INSERT_FAIL)
expected = false;
obj = rhashtable_lookup_fast(ht, &key, test_rht_params);
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->value != i) {
pr_warn("Test failed: Lookup value mismatch %u!=%u\n",
obj->value, i);
return -EINVAL;
}
}
}
return 0;
}
static void test_bucket_stats(struct rhashtable *ht)
{
unsigned int err, total = 0, chain_len = 0;
struct rhashtable_iter hti;
struct rhash_head *pos;
err = rhashtable_walk_init(ht, &hti);
if (err) {
pr_warn("Test failed: allocation error");
return;
}
err = rhashtable_walk_start(&hti);
if (err && err != -EAGAIN) {
pr_warn("Test failed: iterator failed: %d\n", err);
return;
}
while ((pos = rhashtable_walk_next(&hti))) {
if (PTR_ERR(pos) == -EAGAIN) {
pr_info("Info: encountered resize\n");
chain_len++;
continue;
} else if (IS_ERR(pos)) {
pr_warn("Test failed: rhashtable_walk_next() error: %ld\n",
PTR_ERR(pos));
break;
}
total++;
}
rhashtable_walk_stop(&hti);
rhashtable_walk_exit(&hti);
pr_info(" Traversal complete: counted=%u, nelems=%u, entries=%d, table-jumps=%u\n",
total, atomic_read(&ht->nelems), entries, chain_len);
if (total != atomic_read(&ht->nelems) || total != entries)
pr_warn("Test failed: Total count mismatch ^^^");
}
static s64 __init test_rhashtable(struct rhashtable *ht)
{
struct test_obj *obj;
int err;
unsigned int i, insert_fails = 0;
s64 start, end;
/*
* Insertion Test:
* Insert entries into table with all keys even numbers
*/
pr_info(" Adding %d keys\n", entries);
start = ktime_get_ns();
for (i = 0; i < entries; i++) {
struct test_obj *obj = &array[i];
obj->value = i * 2;
err = rhashtable_insert_fast(ht, &obj->node, test_rht_params);
if (err == -ENOMEM || err == -EBUSY) {
/* Mark failed inserts but continue */
obj->value = TEST_INSERT_FAIL;
insert_fails++;
} else if (err) {
return err;
}
}
if (insert_fails)
pr_info(" %u insertions failed due to memory pressure\n",
insert_fails);
test_bucket_stats(ht);
rcu_read_lock();
test_rht_lookup(ht);
rcu_read_unlock();
test_bucket_stats(ht);
pr_info(" Deleting %d keys\n", entries);
for (i = 0; i < entries; i++) {
u32 key = i * 2;
if (array[i].value != TEST_INSERT_FAIL) {
obj = rhashtable_lookup_fast(ht, &key, test_rht_params);
BUG_ON(!obj);
rhashtable_remove_fast(ht, &obj->node, test_rht_params);
}
}
end = ktime_get_ns();
pr_info(" Duration of test: %lld ns\n", end - start);
return end - start;
}
static struct rhashtable ht;
static int __init test_rht_init(void)
{
int i, err;
u64 total_time = 0;
entries = min(entries, MAX_ENTRIES);
test_rht_params.automatic_shrinking = shrinking;
test_rht_params.max_size = max_size;
test_rht_params.nelem_hint = size;
pr_info("Running rhashtable test nelem=%d, max_size=%d, shrinking=%d\n",
size, max_size, shrinking);
for (i = 0; i < runs; i++) {
s64 time;
pr_info("Test %02d:\n", i);
memset(&array, 0, sizeof(array));
err = rhashtable_init(&ht, &test_rht_params);
if (err < 0) {
pr_warn("Test failed: Unable to initialize hashtable: %d\n",
err);
continue;
}
time = test_rhashtable(&ht);
rhashtable_destroy(&ht);
if (time < 0) {
pr_warn("Test failed: return code %lld\n", time);
return -EINVAL;
}
total_time += time;
}
pr_info("Average test time: %llu\n", total_time / runs);
return 0;
}
static void __exit test_rht_exit(void)
{
}
module_init(test_rht_init);
module_exit(test_rht_exit);
MODULE_LICENSE("GPL v2");