test_astobj2_thrash.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2012, David M. Lee, II
 *
 * David M. Lee, II <dlee@digium.com>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */
 
/*
 *! \file \brief Thrash a astobj2 container, for fun and profit.
 *
 * \author\verbatim David M. Lee, II <dlee@digium.com> \endverbatim
 *
 * Inspired by the original hashtest2.c by Steve Murphy <murf@digium.com>.  This test runs
 * several threads manipulating a concurrent astobj2 container to see if they maintain
 * consistency. While the tests attempt to check consistency and error normally, threading
 * errors often result in segfaults.
 * \ingroup tests
 */
 
/*** MODULEINFO
    <depend>TEST_FRAMEWORK</depend>
    <support_level>core</support_level>
 ***/
 
#include "asterisk.h"
 
#include <pthread.h>
#include "asterisk/astobj2.h"
#include "asterisk/hashtab.h"
#include "asterisk/lock.h"
#include "asterisk/module.h"
#include "asterisk/test.h"
#include "asterisk/time.h"
#include "asterisk/utils.h"
 
#define MAX_HASH_ENTRIES 15000
/*
 * Use one of the online calculators to find the first prime number
 * greater than MAX_HASH_ENTRIES / 100.
 */
#define HASH_BUCKETS 151
 
#define COUNT_SLEEP_US 500
#define MAX_TEST_SECONDS 60
 
struct hash_test {
    /*! Unit under test */
    struct ao2_container *to_be_thrashed;
    /*! Number of entries to insert in the grow thread. */
    int max_grow;
    /*! Number of entries added by the grow thread. */
    int grow_count;
    /*! Entries preloaded into the hashtab; to be deleted by the shrink thread */
    int preload;
    /*! When to give up on the tests */
    struct timeval deadline;
};
 
static int alloc_count = 0;
 
static int is_timed_out(struct hash_test const *data) {
    return ast_tvdiff_us(data->deadline, ast_tvnow()) < 0;
}
 
/*! \brief Free test element */
static void ht_delete(void *obj)
{
    ast_atomic_fetchadd_int(&alloc_count, -1);
}
 
/*! \brief Create test element */
static char *ht_new(int i)
{
    const int buflen = 12;
    char *keybuf = ao2_alloc(buflen, ht_delete);
    int needed;
    if (keybuf == NULL) {
        return NULL;
    }
    needed = snprintf(keybuf, buflen, "key%08x", (unsigned)i);
    ast_atomic_fetchadd_int(&alloc_count, 1);
    ast_assert(needed + 1 <= buflen);
    return keybuf;
}
 
/*! \brief Grow the hash data as specified */
static void *hash_test_grow(void *d)
{
    struct hash_test *data = d;
    int i;
 
    for (i = 0; i < data->max_grow; ++i) {
        char *ht;
        if (is_timed_out(data)) {
            printf("Growth timed out at %d\n", i);
            return "Growth timed out";
        }
        ht = ht_new(i);
        if (ht == NULL) {
            return "Allocation failed";
        }
        ao2_link(data->to_be_thrashed, ht);
        ao2_ref(ht, -1);
        ast_atomic_fetchadd_int(&data->grow_count, 1);
    }
    return NULL;
}
 
/*! Randomly lookup data in the hash */
static void *hash_test_lookup(void *d)
{
    struct hash_test *data = d;
    int max;
    unsigned seed = time(NULL);
 
    /* ast_atomic_fetchadd_int provide a memory fence so that the optimizer doesn't
     * optimize away reads.
     */
    while ((max = ast_atomic_fetchadd_int(&data->grow_count, 0)) < data->max_grow) {
        int i;
        char *obj;
        char *from_ao2;
 
        if (is_timed_out(data)) {
            return "Lookup timed out";
        }
 
        if (max == 0) {
            /* No data yet; yield and try again */
            sched_yield();
            continue;
        }
 
        /* Randomly lookup one object from the hash */
        i = rand_r(&seed) % max;
        obj = ht_new(i);
        if (obj == NULL) {
            return "Allocation failed";
        }
        from_ao2 = ao2_find(data->to_be_thrashed, obj, OBJ_POINTER);
        ao2_ref(obj, -1);
        ao2_ref(from_ao2, -1);
        if (from_ao2 == NULL) {
            return "Key unexpectedly missing";
        }
    }
 
    return NULL;
}
 
/*! Delete entries from the hash */
static void *hash_test_shrink(void *d)
{
    const struct hash_test *data = d;
    int i;
 
    for (i = 1; i < data->preload; ++i) {
        char *obj = ht_new(-i);
        char *from_ao2;
 
        if (obj == NULL) {
            return "Allocation failed";
        }
        from_ao2 = ao2_find(data->to_be_thrashed, obj, OBJ_UNLINK | OBJ_POINTER);
 
        ao2_ref(obj, -1);
        if (from_ao2) {
            ao2_ref(from_ao2, -1);
        } else {
            return "Could not find object to delete";
        }
 
        if (is_timed_out(data)) {
            return "Shrink timed out";
        }
    }
 
    return NULL;
}
 
/*! ao2_callback for hash_test_count */
static int increment_count(void *obj, void *arg, int flags) {
    char *ht = obj;
    int *count = arg;
    if (strncmp(ht, "key0", 4) == 0) {
        ++(*count);
    }
    return 0;
}
 
/*! Continuously iterate through all the entries in the hash */
static void *hash_test_count(void *d)
{
    const struct hash_test *data = d;
    int count = 0;
    int last_count = 0;
 
    while (count < data->max_grow) {
        last_count = count;
        count = 0;
        ao2_callback(data->to_be_thrashed, OBJ_MULTIPLE, increment_count, &count);
 
        if (last_count == count) {
            /* Allow other threads to run. */
            usleep(COUNT_SLEEP_US);
        } else if (last_count > count) {
            /* Make sure the ao2 container never shrinks */
            return "ao2 container unexpectedly shrank";
        }
 
        if (is_timed_out(data)) {
            return "Count timed out";
        }
    }
 
    /* Successfully iterated over all of the expected elements */
    return NULL;
}
 
static int hash_string(const void *obj, const int flags)
{
    return ast_hashtab_hash_string_nocase(obj);
}
 
static int compare_strings(void *lhs, void *rhs, int flags)
{
    const char *lhs_str = lhs;
    const char *rhs_str = rhs;
    if (strcasecmp(lhs_str, rhs_str) == 0) {
        return CMP_MATCH | CMP_STOP;
    } else {
        return 0;
    }
}
 
AST_TEST_DEFINE(hash_test)
{
    enum ast_test_result_state res = AST_TEST_PASS;
    struct hash_test data = {};
    pthread_t grow_thread, count_thread, lookup_thread, shrink_thread;
    void *thread_results;
    int i;
 
    switch (cmd) {
    case TEST_INIT:
        info->name = "thrash";
        info->category = "/main/astobj2/";
        info->summary = "Testing astobj2 container concurrency";
        info->description = "Test astobj2 container concurrency correctness.";
        return AST_TEST_NOT_RUN;
    case TEST_EXECUTE:
        break;
    }
 
    ast_test_status_update(test, "Executing hash concurrency test...\n");
    data.preload = MAX_HASH_ENTRIES / 2;
    data.max_grow = MAX_HASH_ENTRIES - data.preload;
    data.deadline = ast_tvadd(ast_tvnow(), ast_tv(MAX_TEST_SECONDS, 0));
    data.to_be_thrashed = ao2_container_alloc_hash(AO2_ALLOC_OPT_LOCK_MUTEX, 0,
        HASH_BUCKETS, hash_string, NULL, compare_strings);
 
    if (data.to_be_thrashed == NULL) {
        ast_test_status_update(test, "Allocation failed\n");
        /* Nothing needs to be freed; early return is fine */
        return AST_TEST_FAIL;
    }
 
    /* preload with data to delete */
    for (i = 1; i < data.preload; ++i) {
        char *ht = ht_new(-i);
        if (ht == NULL) {
            ast_test_status_update(test, "Allocation failed\n");
            ao2_ref(data.to_be_thrashed, -1);
            return AST_TEST_FAIL;
        }
        ao2_link(data.to_be_thrashed, ht);
        ao2_ref(ht, -1);
    }
 
    /* add data.max_grow entries to the ao2 container */
    ast_pthread_create(&grow_thread, NULL, hash_test_grow, &data);
    /* continually count the keys added by the grow thread */
    ast_pthread_create(&count_thread, NULL, hash_test_count, &data);
    /* continually lookup keys added by the grow thread */
    ast_pthread_create(&lookup_thread, NULL, hash_test_lookup, &data);
    /* delete all keys preloaded into the ao2 container */
    ast_pthread_create(&shrink_thread, NULL, hash_test_shrink, &data);
 
    pthread_join(grow_thread, &thread_results);
    if (thread_results != NULL) {
        ast_test_status_update(test, "Growth thread failed: %s\n",
            (char *)thread_results);
        res = AST_TEST_FAIL;
    }
 
    pthread_join(count_thread, &thread_results);
    if (thread_results != NULL) {
        ast_test_status_update(test, "Count thread failed: %s\n",
            (char *)thread_results);
        res = AST_TEST_FAIL;
    }
 
    pthread_join(lookup_thread, &thread_results);
    if (thread_results != NULL) {
        ast_test_status_update(test, "Lookup thread failed: %s\n",
            (char *)thread_results);
        res = AST_TEST_FAIL;
    }
 
    pthread_join(shrink_thread, &thread_results);
    if (thread_results != NULL) {
        ast_test_status_update(test, "Shrink thread failed: %s\n",
            (char *)thread_results);
        res = AST_TEST_FAIL;
    }
 
    if (ao2_container_count(data.to_be_thrashed) != data.max_grow) {
        ast_test_status_update(test,
            "Invalid ao2 container size. Expected: %d, Actual: %d\n",
            data.max_grow, ao2_container_count(data.to_be_thrashed));
        res = AST_TEST_FAIL;
    }
 
    ao2_ref(data.to_be_thrashed, -1);
 
    /* check for object leaks */
    if (ast_atomic_fetchadd_int(&alloc_count, 0) != 0) {
        ast_test_status_update(test, "Leaked %d objects!\n",
            ast_atomic_fetchadd_int(&alloc_count, 0));
        res = AST_TEST_FAIL;
    }
 
    return res;
}
 
static int unload_module(void)
{
    AST_TEST_UNREGISTER(hash_test);
    return 0;
}
 
static int load_module(void)
{
    AST_TEST_REGISTER(hash_test);
    return AST_MODULE_LOAD_SUCCESS;
}
 
AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "astobj2 container thrash test");