test_astobj2_thrash.c

Go to the documentation of this file.

/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2012, David M. Lee, II
 *
 * David M. Lee, II <[email protected]>
 *
 * 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 <[email protected]> \endverbatim
 *
 * Inspired by the original hashtest2.c by Steve Murphy <[email protected]>.  This test runs
 * several threads manipulatings 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 enteries 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");