// SPDX-License-Identifier: GPL-2.0-only
/*
* Resizable, Scalable, Concurrent Hash Table
*
* Copyright (c) 2014-2015 Thomas Graf <[email protected]>
* Copyright (c) 2008-2014 Patrick McHardy <[email protected]>
*/
/**************************************************************************
* Self Test
**************************************************************************/
#include <linux/init.h>
#include <linux/jhash.h>
#include <linux/kernel.h>
#include <linux/kthread.h>
#include <linux/module.h>
#include <linux/rcupdate.h>
#include <linux/rcupdate_wait.h>
#include <linux/rhashtable.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/random.h>
#include <linux/vmalloc.h>
#include <linux/wait.h>
#define MAX_ENTRIES 1000000
#define TEST_INSERT_FAIL INT_MAX
static int parm_entries = 50000;
module_param(parm_entries, int, 0);
MODULE_PARM_DESC(parm_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 = 0;
module_param(max_size, int, 0);
MODULE_PARM_DESC(max_size, "Maximum table size (default: calculated)");
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)");
static int tcount = 10;
module_param(tcount, int, 0);
MODULE_PARM_DESC(tcount, "Number of threads to spawn (default: 10)");
static bool enomem_retry = false;
module_param(enomem_retry, bool, 0);
MODULE_PARM_DESC(enomem_retry, "Retry insert even if -ENOMEM was returned (default: off)");
struct test_obj_val {
int id;
int tid;
};
struct test_obj {
struct test_obj_val value;
struct rhash_head node;
};
struct test_obj_rhl {
struct test_obj_val value;
struct rhlist_head list_node;
};
struct thread_data {
unsigned int entries;
int id;
struct task_struct *task;
struct test_obj *objs;
};
static u32 my_hashfn(const void *data, u32 len, u32 seed)
{
const struct test_obj_rhl *obj = data;
return (obj->value.id % 10);
}
static int my_cmpfn(struct rhashtable_compare_arg *arg, const void *obj)
{
const struct test_obj_rhl *test_obj = obj;
const struct test_obj_val *val = arg->key;
return test_obj->value.id - val->id;
}
static struct rhashtable_params test_rht_params = {
.head_offset = offsetof(struct test_obj, node),
.key_offset = offsetof(struct test_obj, value),
.key_len = sizeof(struct test_obj_val),
.hashfn = jhash,
};
static struct rhashtable_params test_rht_params_dup = {
.head_offset = offsetof(struct test_obj_rhl, list_node),
.key_offset = offsetof(struct test_obj_rhl, value),
.key_len = sizeof(struct test_obj_val),
.hashfn = jhash,
.obj_hashfn = my_hashfn,
.obj_cmpfn = my_cmpfn,
.nelem_hint = 128,
.automatic_shrinking = false,
};
static atomic_t startup_count;
static DECLARE_WAIT_QUEUE_HEAD(startup_wait);
static int insert_retry(struct rhashtable *ht, struct test_obj *obj,
const struct rhashtable_params params)
{
int err, retries = -1, enomem_retries = 0;
do {
retries++;
cond_resched();
err = rhashtable_insert_fast(ht, &obj->node, params);
if (err == -ENOMEM && enomem_retry) {
enomem_retries++;
err = -EBUSY;
}
} while (err == -EBUSY);
if (enomem_retries)
pr_info(" %u insertions retried after -ENOMEM\n",
enomem_retries);
return err ? : retries;
}
static int __init test_rht_lookup(struct rhashtable *ht, struct test_obj *array,
unsigned int entries)
{
unsigned int i;
for (i = 0; i < entries; i++) {
struct test_obj *obj;
bool expected = !(i % 2);
struct test_obj_val key = {
.id = i,
};
if (array[i / 2].value.id == 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.id);
return -ENOENT;
} else if (!expected && obj) {
pr_warn("Test failed: Unexpected entry found for key %u\n",
key.id);
return -EEXIST;
} else if (expected && obj) {
if (obj->value.id != i) {
pr_warn("Test failed: Lookup value mismatch %u!=%u\n",
obj->value.id, i);
return -EINVAL;
}
}
cond_resched_rcu();
}
return 0;
}
static void test_bucket_stats(struct rhashtable *ht, unsigned int entries)
{
unsigned int total = 0, chain_len = 0;
struct rhashtable_iter hti;
struct rhash_head *pos;
rhashtable_walk_enter(ht, &hti);
rhashtable_walk_start(&hti);
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 *array,
unsigned int entries)
{
struct test_obj *obj;
int err;
unsigned int i, insert_retries = 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.id = i * 2;
err = insert_retry(ht, obj, test_rht_params);
if (err > 0)
insert_retries += err;
else if (err)
return err;
}
if (insert_retries)
pr_info(" %u insertions retried due to memory pressure\n",
insert_retries);
test_bucket_stats(ht, entries);
rcu_read_lock();
test_rht_lookup(ht, array, entries);
rcu_read_unlock();
test_bucket_stats(ht, entries);
pr_info(" Deleting %d keys\n", entries);
for (i = 0; i < entries; i++) {
struct test_obj_val key = {
.id = i * 2,
};
if (array[i].value.id != TEST_INSERT_FAIL) {
obj = rhashtable_lookup_fast(ht, &key, test_rht_params);
BUG_ON(!obj);
rhashtable_remove_fast(ht, &obj->node, test_rht_params);
}
cond_resched();
}
end = ktime_get_ns();
pr_info(" Duration of test: %lld ns\n", end - start);
return end - start;
}
static struct rhashtable ht;
static struct rhltable rhlt;
static int __init test_rhltable(unsigned int entries)
{
struct test_obj_rhl *rhl_test_objects;
unsigned long *obj_in_table;
unsigned int i, j, k;
int ret, err;
if (entries == 0)
entries = 1;
rhl_test_objects = vzalloc(array_size(entries,
sizeof(*rhl_test_objects)));
if (!rhl_test_objects)
return -ENOMEM;
ret = -ENOMEM;
obj_in_table = vzalloc(array_size(sizeof(unsigned long),
BITS_TO_LONGS(entries)));
if (!obj_in_table)
goto out_free;
err = rhltable_init(&rhlt, &test_rht_params);
if (WARN_ON(err))
goto out_free;
k = get_random_u32();
ret = 0;
for (i = 0; i < entries; i++) {
rhl_test_objects[i].value.id = k;
err = rhltable_insert(&rhlt, &rhl_test_objects[i].list_node,
test_rht_params);
if (WARN(err, "error %d on element %d\n", err, i))
break;
if (err == 0)
set_bit(i, obj_in_table);
}
if (err)
ret = err;
pr_info("test %d add/delete pairs into rhlist\n", entries);
for (i = 0; i < entries; i++) {
struct rhlist_head *h, *pos;
struct test_obj_rhl *obj;
struct test_obj_val key = {
.id = k,
};
bool found;
rcu_read_lock();
h = rhltable_lookup(&rhlt, &key, test_rht_params);
if (WARN(!h, "key not found during iteration %d of %d", i, entries)) {
rcu_read_unlock();
break;
}
if (i) {
j = i - 1;
rhl_for_each_entry_rcu(obj, pos, h, list_node) {
if (WARN(pos == &rhl_test_objects[j].list_node, "old element found, should be gone"))
break;
}
}
cond_resched_rcu();
found = false;
rhl_for_each_entry_rcu(obj, pos, h, list_node) {
if (pos == &rhl_test_objects[i].list_node) {
found = true;
break;
}
}
rcu_read_unlock();
if (WARN(!found, "element %d not found", i))
break;
err = rhltable_remove(&rhlt, &rhl_test_objects[i].list_node, test_rht_params);
WARN(err, "rhltable_remove: err %d for iteration %d\n", err, i);
if (err == 0)
clear_bit(i, obj_in_table);
}
if (ret == 0 && err)
ret = err;
for (i = 0; i < entries; i++) {
WARN(test_bit(i, obj_in_table), "elem %d allegedly still present", i);
err = rhltable_insert(&rhlt, &rhl_test_objects[i].list_node,
test_rht_params);
if (WARN(err, "error %d on element %d\n", err, i))
break;
if (err == 0)
set_bit(i, obj_in_table);
}
pr_info("test %d random rhlist add/delete operations\n", entries);
for (j = 0; j < entries; j++) {
u32 i = get_random_u32_below(entries);
u32 prand = get_random_u32_below(4);
cond_resched();
err = rhltable_remove(&rhlt, &rhl_test_objects[i].list_node, test_rht_params);
if (test_bit(i, obj_in_table)) {
clear_bit(i, obj_in_table);
if (WARN(err, "cannot remove element at slot %d", i))
continue;
} else {
if (WARN(err != -ENOENT, "removed non-existent element %d, error %d not %d",
i, err, -ENOENT))
continue;
}
if (prand & 1) {
err = rhltable_insert(&rhlt, &rhl_test_objects[i].list_node, test_rht_params);
if (err == 0) {
if (WARN(test_and_set_bit(i, obj_in_table), "succeeded to insert same object %d", i))
continue;
} else {
if (WARN(!test_bit(i, obj_in_table), "failed to insert object %d", i))
continue;
}
}
if (prand & 2) {
i = get_random_u32_below(entries);
if (test_bit(i, obj_in_table)) {
err = rhltable_remove(&rhlt, &rhl_test_objects[i].list_node, test_rht_params);
WARN(err, "cannot remove element at slot %d", i);
if (err == 0)
clear_bit(i, obj_in_table);
} else {
err = rhltable_insert(&rhlt, &rhl_test_objects[i].list_node, test_rht_params);
WARN(err, "failed to insert object %d", i);
if (err == 0)
set_bit(i, obj_in_table);
}
}
}
for (i = 0; i < entries; i++) {
cond_resched();
err = rhltable_remove(&rhlt, &rhl_test_objects[i].list_node, test_rht_params);
if (test_bit(i, obj_in_table)) {
if (WARN(err, "cannot remove element at slot %d", i))
continue;
} else {
if (WARN(err != -ENOENT, "removed non-existent element, error %d not %d",
err, -ENOENT))
continue;
}
}
rhltable_destroy(&rhlt);
out_free:
vfree(rhl_test_objects);
vfree(obj_in_table);
return ret;
}
static int __init test_rhashtable_max(struct test_obj *array,
unsigned int entries)
{
unsigned int i;
int err;
test_rht_params.max_size = roundup_pow_of_two(entries / 8);
err = rhashtable_init(&ht, &test_rht_params);
if (err)
return err;
for (i = 0; i < ht.max_elems; i++) {
struct test_obj *obj = &array[i];
obj->value.id = i * 2;
err = insert_retry(&ht, obj, test_rht_params);
if (err < 0)
return err;
}
err = insert_retry(&ht, &array[ht.max_elems], test_rht_params);
if (err == -E2BIG) {
err = 0;
} else {
pr_info("insert element %u should have failed with %d, got %d\n",
ht.max_elems, -E2BIG, err);
if (err == 0)
err = -1;
}
rhashtable_destroy(&ht);
return err;
}
static unsigned int __init print_ht(struct rhltable *rhlt)
{
struct rhashtable *ht;
const struct bucket_table *tbl;
char buff[512] = "";
int offset = 0;
unsigned int i, cnt = 0;
ht = &rhlt->ht;
/* Take the mutex to avoid RCU warning */
mutex_lock(&ht->mutex);
tbl = rht_dereference(ht->tbl, ht);
for (i = 0; i < tbl->size; i++) {
struct rhash_head *pos, *next;
struct test_obj_rhl *p;
pos = rht_ptr_exclusive(tbl->buckets + i);
next = !rht_is_a_nulls(pos) ? rht_dereference(pos->next, ht) : NULL;
if (!rht_is_a_nulls(pos)) {
offset += sprintf(buff + offset, "\nbucket[%d] -> ", i);
}
while (!rht_is_a_nulls(pos)) {
struct rhlist_head *list = container_of(pos, struct rhlist_head, rhead);
offset += sprintf(buff + offset, "[[");
do {
pos = &list->rhead;
list = rht_dereference(list->next, ht);
p = rht_obj(ht, pos);
offset += sprintf(buff + offset, " val %d (tid=%d)%s", p->value.id, p->value.tid,
list? ", " : " ");
cnt++;
} while (list);
pos = next,
next = !rht_is_a_nulls(pos) ?
rht_dereference(pos->next, ht) : NULL;
offset += sprintf(buff + offset, "]]%s", !rht_is_a_nulls(pos) ? " -> " : "");
}
}
printk(KERN_ERR "\n---- ht: ----%s\n-------------\n", buff);
mutex_unlock(&ht->mutex);
return cnt;
}
static int __init test_insert_dup(struct test_obj_rhl *rhl_test_objects,
int cnt, bool slow)
{
struct rhltable *rhlt;
unsigned int i, ret;
const char *key;
int err = 0;
rhlt = kmalloc(sizeof(*rhlt), GFP_KERNEL);
if (WARN_ON(!rhlt))
return -EINVAL;
err = rhltable_init(rhlt, &test_rht_params_dup);
if (WARN_ON(err)) {
kfree(rhlt);
return err;
}
for (i = 0; i < cnt; i++) {
rhl_test_objects[i].value.tid = i;
key = rht_obj(&rhlt->ht, &rhl_test_objects[i].list_node.rhead);
key += test_rht_params_dup.key_offset;
if (slow) {
err = PTR_ERR(rhashtable_insert_slow(&rhlt->ht, key,
&rhl_test_objects[i].list_node.rhead));
if (err == -EAGAIN)
err = 0;
} else
err = rhltable_insert(rhlt,
&rhl_test_objects[i].list_node,
test_rht_params_dup);
if (WARN(err, "error %d on element %d/%d (%s)\n", err, i, cnt, slow? "slow" : "fast"))
goto skip_print;
}
ret = print_ht(rhlt);
WARN(ret != cnt, "missing rhltable elements (%d != %d, %s)\n", ret, cnt, slow? "slow" : "fast");
skip_print:
rhltable_destroy(rhlt);
kfree(rhlt);
return 0;
}
static int __init test_insert_duplicates_run(void)
{
struct test_obj_rhl rhl_test_objects[3] = {};
pr_info("test inserting duplicates\n");
/* two different values that map to same bucket */
rhl_test_objects[0].value.id = 1;
rhl_test_objects[1].value.id = 21;
/* and another duplicate with same as [0] value
* which will be second on the bucket list */
rhl_test_objects[2].value.id = rhl_test_objects[0].value.id;
test_insert_dup(rhl_test_objects, 2, false);
test_insert_dup(rhl_test_objects, 3, false);
test_insert_dup(rhl_test_objects, 2, true);
test_insert_dup(rhl_test_objects, 3, true);
return 0;
}
static int thread_lookup_test(struct thread_data *tdata)
{
unsigned int entries = tdata->entries;
int i, err = 0;
for (i = 0; i < entries; i++) {
struct test_obj *obj;
struct test_obj_val key = {
.id = i,
.tid = tdata->id,
};
obj = rhashtable_lookup_fast(&ht, &key, test_rht_params);
if (obj && (tdata->objs[i].value.id == TEST_INSERT_FAIL)) {
pr_err(" found unexpected object %d-%d\n", key.tid, key.id);
err++;
} else if (!obj && (tdata->objs[i].value.id != TEST_INSERT_FAIL)) {
pr_err(" object %d-%d not found!\n", key.tid, key.id);
err++;
} else if (obj && memcmp(&obj->value, &key, sizeof(key))) {
pr_err(" wrong object returned (got %d-%d, expected %d-%d)\n",
obj->value.tid, obj->value.id, key.tid, key.id);
err++;
}
cond_resched();
}
return err;
}
static int threadfunc(void *data)
{
int i, step, err = 0, insert_retries = 0;
struct thread_data *tdata = data;
if (atomic_dec_and_test(&startup_count))
wake_up(&startup_wait);
if (wait_event_interruptible(startup_wait, atomic_read(&startup_count) == -1)) {
pr_err(" thread[%d]: interrupted\n", tdata->id);
goto out;
}
for (i = 0; i < tdata->entries; i++) {
tdata->objs[i].value.id = i;
tdata->objs[i].value.tid = tdata->id;
err = insert_retry(&ht, &tdata->objs[i], test_rht_params);
if (err > 0) {
insert_retries += err;
} else if (err) {
pr_err(" thread[%d]: rhashtable_insert_fast failed\n",
tdata->id);
goto out;
}
}
if (insert_retries)
pr_info(" thread[%d]: %u insertions retried due to memory pressure\n",
tdata->id, insert_retries);
err = thread_lookup_test(tdata);
if (err) {
pr_err(" thread[%d]: rhashtable_lookup_test failed\n",
tdata->id);
goto out;
}
for (step = 10; step > 0; step--) {
for (i = 0; i < tdata->entries; i += step) {
if (tdata->objs[i].value.id == TEST_INSERT_FAIL)
continue;
err = rhashtable_remove_fast(&ht, &tdata->objs[i].node,
test_rht_params);
if (err) {
pr_err(" thread[%d]: rhashtable_remove_fast failed\n",
tdata->id);
goto out;
}
tdata->objs[i].value.id = TEST_INSERT_FAIL;
cond_resched();
}
err = thread_lookup_test(tdata);
if (err) {
pr_err(" thread[%d]: rhashtable_lookup_test (2) failed\n",
tdata->id);
goto out;
}
}
out:
while (!kthread_should_stop()) {
set_current_state(TASK_INTERRUPTIBLE);
schedule();
}
return err;
}
static int __init test_rht_init(void)
{
unsigned int entries;
int i, err, started_threads = 0, failed_threads = 0;
u64 total_time = 0;
struct thread_data *tdata;
struct test_obj *objs;
if (parm_entries < 0)
parm_entries = 1;
entries = min(parm_entries, MAX_ENTRIES);
test_rht_params.automatic_shrinking = shrinking;
test_rht_params.max_size = max_size ? : roundup_pow_of_two(entries);
test_rht_params.nelem_hint = size;
objs = vzalloc(array_size(sizeof(struct test_obj),
test_rht_params.max_size + 1));
if (!objs)
return -ENOMEM;
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(objs, 0, test_rht_params.max_size * sizeof(struct test_obj));
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, objs, entries);
rhashtable_destroy(&ht);
if (time < 0) {
vfree(objs);
pr_warn("Test failed: return code %lld\n", time);
return -EINVAL;
}
total_time += time;
}
pr_info("test if its possible to exceed max_size %d: %s\n",
test_rht_params.max_size, test_rhashtable_max(objs, entries) == 0 ?
"no, ok" : "YES, failed");
vfree(objs);
do_div(total_time, runs);
pr_info("Average test time: %llu\n", total_time);
test_insert_duplicates_run();
if (!tcount)
return 0;
pr_info("Testing concurrent rhashtable access from %d threads\n",
tcount);
atomic_set(&startup_count, tcount);
tdata = vzalloc(array_size(tcount, sizeof(struct thread_data)));
if (!tdata)
return -ENOMEM;
objs = vzalloc(array3_size(sizeof(struct test_obj), tcount, entries));
if (!objs) {
vfree(tdata);
return -ENOMEM;
}
test_rht_params.max_size = max_size ? :
roundup_pow_of_two(tcount * entries);
err = rhashtable_init(&ht, &test_rht_params);
if (err < 0) {
pr_warn("Test failed: Unable to initialize hashtable: %d\n",
err);
vfree(tdata);
vfree(objs);
return -EINVAL;
}
for (i = 0; i < tcount; i++) {
tdata[i].id = i;
tdata[i].entries = entries;
tdata[i].objs = objs + i * entries;
tdata[i].task = kthread_run(threadfunc, &tdata[i],
"rhashtable_thrad[%d]", i);
if (IS_ERR(tdata[i].task)) {
pr_err(" kthread_run failed for thread %d\n", i);
atomic_dec(&startup_count);
} else {
started_threads++;
}
}
if (wait_event_interruptible(startup_wait, atomic_read(&startup_count) == 0))
pr_err(" wait_event interruptible failed\n");
/* count is 0 now, set it to -1 and wake up all threads together */
atomic_dec(&startup_count);
wake_up_all(&startup_wait);
for (i = 0; i < tcount; i++) {
if (IS_ERR(tdata[i].task))
continue;
if ((err = kthread_stop(tdata[i].task))) {
pr_warn("Test failed: thread %d returned: %d\n",
i, err);
failed_threads++;
}
}
rhashtable_destroy(&ht);
vfree(tdata);
vfree(objs);
/*
* rhltable_remove is very expensive, default values can cause test
* to run for 2 minutes or more, use a smaller number instead.
*/
err = test_rhltable(entries / 16);
pr_info("Started %d threads, %d failed, rhltable test returns %d\n",
started_threads, failed_threads, err);
return 0;
}
static void __exit test_rht_exit(void)
{
}
module_init(test_rht_init);
module_exit(test_rht_exit);
MODULE_DESCRIPTION("Resizable, Scalable, Concurrent Hash Table test module");
MODULE_LICENSE("GPL v2");
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