The malloc_test Module

Andrei Pelinescu-Onciul

   iptelorg GmbH

   Copyright © 2010 iptelorg GmbH
     __________________________________________________________________

   List of Examples

   1. Set check_content in the config file
   2. Set check_content at runtime via sercmd
   3. men_alloc usage
   4. mem_free usage
   5. mt.mem_alloc usage
   6. mt.mem_free usage
   7. mt.mem_used usage
   8. mt.mem_rnd_alloc usage
   9. mt.mem_test_start usage
   10. mt.mem_test_stop usage
   11. mt.mem_test_destroy usage
   12. mt.mem_test_destroy_all usage
   13. mt.mem_test_list usage

1. Overview

   This is a debugging/test module. It implements functions (both script
   and rpcs) that can be used to stress the memory allocator or force
   memory leaks.

Warning

   This module should never be used in a production environment.

2. Parameters

   2.1. check_content

2.1. check_content

   When doing the tests, check also for the possibility of the memory
   being overwritten. When activated, the allocated memory will be filled
   with a special pattern, that will be checked on free.

   Default: 0 (off).

   It can be changed also at runtime, via the rpc interface.

   Example 1.  Set check_content in the config file
modparam("malloc_test", "check_content", 1)

   Example 2.  Set check_content at runtime via sercmd
$ sercmd cfg.set_now_int malloc_test check_content 1

3. Functions

   3.1. mt_mem_alloc(size)
   3.2. mt_mem_free()

3.1. mt_mem_alloc(size)

   Allocates size bytes.

Note

   This is a debugging function for simulating memory leaks or stressing
   the memory allocator. It should not be used in production setups

   Example 3. men_alloc usage
...
mem_alloc(1048576); # 1MB
...

3.2. mt_mem_free()

   Frees all the memory allocated with mem_alloc() up to this point.

Note

   This is a debugging function for simulating memory leaks or stressing
   the memory allocator. It should not be used in production setups

   Example 4. mem_free usage
...
mem_free();
...

4. malloc_test RPC Functions

   4.1. mt.mem_alloc size [unit]
   4.2. mt.mem_free [size] [unit]
   4.3. mt.mem_used [unit]
   4.4. mt.mem_rnd_alloc min max total [unit]
   4.5. mt.mem_test_start min max total min_int max_int total_time [unit]
   4.6. mt.mem_test_stop id
   4.7. mt.mem_test_destroy id
   4.8. mt.mem_test_destroy_all id
   4.9. mt.mem_test_list [id] [unit]

4.1.  mt.mem_alloc size [unit]

   Allocates the specified number of bytes. unit is optional and can be
   one of:
     * b - bytes
     * k - KB
     * m - MB
     * g - GB

   Example 5. mt.mem_alloc usage
 $ sercmd mt.mem_alloc 10 k

4.2.  mt.mem_free [size] [unit]

   Frees at least size bytes from the memory allocated by other
   malloc_test functions (e.g. mt.mem_alloc).

   size is optional. If missing, everything will be freed.

   unit is optional and can be one of:
     * b - bytes
     * k - KB
     * m - MB
     * g - GB

   Example 6. mt.mem_free usage
 $ sercmd mt.mem_free 1 m

4.3.  mt.mem_used [unit]

   Returns/displays how many bytes are allocated. The default unit is
   bytes (for all the possible units see above).

   unit is optional and can be one of:
     * b - bytes
     * k - KB
     * m - MB
     * g - GB

   Example 7. mt.mem_used usage
 $ sercmd mt.mem_used
9221460

4.4. mt.mem_rnd_alloc min max total [unit]

   Allocates total_size memory, in pieces of random size between min ..
   max (inclusive). unit is optional and represents the unit for all the
   given sizes (see above).

   Example 8. mt.mem_rnd_alloc usage
 $ sercmd mt.mem_rnd_alloc 1 64 10240 k

4.5.  mt.mem_test_start min max total min_int max_int total_time [unit]

   Starts a malloc test that will take total_time to execute. Memory
   allocations will be performed at intervals randomly chosen between
   min_int and max_int (in ms). Each allocation will have a randomly
   chosen size between min and max unit bytes. After total unit bytes are
   allocated, everything is released/freed again and the allocations are
   restarted. All the times are expressed in milliseconds. unit is
   optional and represents the unit for all the given sizes (see above).

   Several tests can be run in parallel.

   Returns the test id.

   Example 9. mt.mem_test_start usage
 $ sercmd mt.mem_test_start 15 64 25000 128 1500 3600000 k
1

4.6.  mt.mem_test_stop id

   Stops the test indentified by id.

   Example 10. mt.mem_test_stop usage
 $ sercmd mt.mem_test_stop 1

4.7.  mt.mem_test_destroy id

   Destroys the test indentified by id (besides stopping it, it also frees
   all the data, including the statistics).

   Example 11. mt.mem_test_destroy usage
 $ sercmd mt.mem_test_destroy 1

4.8.  mt.mem_test_destroy_all id

   Destroys all the running or stopped tests.

   Example 12. mt.mem_test_destroy_all usage
 $ sercmd mt.mem_test_destroy_all

4.9.  mt.mem_test_list [id] [unit]

   Returns/displays data about the test identified by id, or if no id is
   specified, it lists all the tests (running or stopped).

   unit is optional. The default is is bytes (for all the possible units
   see above).

   Example 13. mt.mem_test_list usage
 $ sercmd mt.mem_test_list
{
        ID           : 2
        run time (s) : 1471
        remaining (s): 2128
        allocations  : 1749
        errors       : 24
        overflows    : 2
        total alloc  : 69614530
        min          : 15360
        max          : 65536
        total        : 25600000
}
{
        ID           : 1
        run time (s) : 3600
        remaining (s): 0
        allocations  : 4268
        errors       : 640
        overflows    : 4
        total alloc  : 144220713
        min          : 15360
        max          : 65536
        total        : 29696000
}
