Abstract:
A method, system, and computer usable program product for on-demand monitoring of memory usage are provided in the illustrative embodiments. An indication of a memory leak in an application is detected where the application is operating in a data processing system and using a memory associated with the data processing system. An instruction to begin monitoring a memory usage of the application is received responsive to the detection. Responsive to receiving the instruction to begin, the memory usage of the application is monitored. An instruction to dump a data related to the monitoring is received and the data is dumped. An instruction to end the monitoring is received and the monitoring is ended. The detecting, the beginning, the dumping, and the ending may occur while the application remains in operation and while the application uses the memory. The memory leak is confirmed using the data.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to an improved data processing system, and in particular, to a computer implemented method for managing data processing systems. Still more particularly, the present invention relates to a computer implemented method, system, and computer usable program code for on-demand monitoring of memory usage by an application in a data processing system. 
     2. Description of the Related Art 
     Software applications executing in a data processing system use memory associated with that data processing system. For example, an application uses the memory for storing instructions needed to execute the application&#39;s intended functions, data needed by those instructions, results of computations, and temporary information relevant to the execution of the application. 
     Generally, applications do not reserve all the memory space at once the application anticipates using over the course of the application&#39;s execution. Applications request and reserve an amount of memory when they have a need for the memory space. This process of requesting and reserving an amount of memory space is called memory allocation. Generally, a memory management system in the data processing system allocates memory space to a requesting application. The memory management system is generally a memory management functional unit of the operating system operating the data processing system. 
     Once an application does not need an allocated memory space, the application frees the memory space. The memory management system then deallocates the freed memory space for use by other applications. The process of deallocating memory in this manner is called memory deallocation. 
     Ideally, an application should eventually free all the memory that was allocated to the application. However, many applications fail to free some segments of memory spaces that are allocated to the application at some time in their execution. Failing to free memory that was allocated to an application and that the application does not need anymore is called a memory leak. Memory leak is an undesirable characteristic in an application, and software designers take great pains to ensure that the application does not have a memory leak problem. 
     Memory leak in an application executing on a data processing system can deteriorate the overall performance of the data processing system over time. In such cases, the memory management system allocates an amount of memory space to the application, and the application frees only a part of that memory. Over a period of time, this cycle of allocating memory and freeing less than the amount that was allocated causes a net reduction in memory resources that are available for allocating to other applications in the data processing system. The reduction in memory resources causes applications to perform slower, degrading the overall performance of the data processing system. 
     SUMMARY OF THE INVENTION 
     The illustrative embodiments provide a method, system, and computer usable program product for on-demand monitoring of memory usage. An indication of a memory leak in an application is detected where the application is operating in a data processing system and using a memory associated with the data processing system. An instruction to begin monitoring a memory usage of the application is received responsive to the detection. Responsive to receiving the instruction to begin, the memory usage of the application is monitored. An instruction to dump a data related to the monitoring is received. The data is dumped responsive to receiving the instruction to dump. An instruction to end the monitoring is received. The monitoring is ended, responsive to receiving the instruction to end. The detecting, the beginning, the dumping, and the ending may occur while the application remains in operation and while the application uses the memory. The memory leak is confirmed using the data. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself; however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein: 
         FIG. 1  depicts a pictorial representation of a network of data processing systems in which illustrative embodiments may be implemented; 
         FIG. 2  depicts a block diagram of a data processing system in which illustrative embodiments may be implemented; 
         FIG. 3  depicts a block diagram of an application using memory in accordance with an illustrative embodiment; 
         FIG. 4  depicts a block diagram of on-demand monitoring of memory usage in accordance with an illustrative embodiment; 
         FIG. 5  depicts a block diagram of triggering a memory monitoring program in accordance with an illustrative embodiment; 
         FIG. 6  depicts a block diagram of an exemplary manner of sending commands to a memory monitoring program in accordance with an illustrative embodiment; 
         FIG. 7  depicts a block diagram of another exemplary manner of sending commands to a memory monitoring program in accordance with an illustrative embodiment; 
         FIG. 8  depicts a flowchart of a process of instructing a memory monitoring program in accordance with an illustrative embodiment; and 
         FIG. 9  depicts a flowchart of a process of on-demand monitoring of memory usage in accordance with an illustrative embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Presently, when a user suspects that an application has a memory leak, the user can use a variety of commercial debugging tools that may help locate the cause of the memory leak. The illustrative embodiments recognize that even with the debugging tools, locating the cause of the memory leak is a cumbersome and sometimes unacceptable process. For example, some debugging tools require that the suspect application be shutdown and restarted in conjunction with the debugging tool. In a business-critical data processing environment, shutting down an application or a data processing system may be an unacceptable step in the debugging process. 
     As another example, some debugging tools require that the suspect application be re-linked or some time even recompiled in conjunction with the debugging tool&#39;s libraries so that the debugging tool may detect the source of the memory leak. Again, the illustrative embodiments recognize, in a high-traffic or business critical data processing environment, re-linking the tool library or recompiling the source code may be unacceptable. Furthermore, for commercially procured applications that may be suspected of having a memory leak, the debugging tool&#39;s library or the application source code may simply be unavailable to the user without extensive licensing agreement, ruling out the recompilation or re-linking option in most cases. 
     Additionally, most debugging tools are intrusive by their very nature. The illustrative embodiments recognize that even if a debugging tool is not as disruptive as in the above examples, a user may not allow debugging tools to be installed on their data processing systems, especially in production environments where only business-purposed software may be installed and run. 
     Because of these and other similar problems, debugging a suspect application for a memory leak is not a desirable solution to memory leaks. In many cases, therefore, technical support providers and software designers attempt to recreate the memory leak problem in their labs by carefully collect as much circumstantial information from the data processing environment where the suspect application may be executing, and replicating those circumstances in a laboratory setup. 
     The illustrative embodiments recognize that replicating a tricky problem like a memory leak is labor intensive and is often inconclusive. Even when a team is able to replicate the problem and locate the source of the memory leak, the exercise often takes a long time resulting in unacceptable disruption in the user&#39;s business. 
     To address these and other problems related to memory leaks, the illustrative embodiments provide a method, system, and computer usable program product for on-demand monitoring of memory usage by an application in a data processing system. The illustrative embodiments may be used in conjunction with any application that may have a potential for a memory leak in the present or future version of the application. 
     For example, the illustrative embodiments may be implemented with a directory server, a name server, a user location service server (ULS server), an application server, a web server, a proxy server, a mail server, a feed server, or any other type of data server. The illustrative embodiments may also be implemented with any business application, such as, for example, a word processing application, a graphics application, a spreadsheet application, accounting software, a gaming application, or any other type of business application. The illustrative embodiments may also be implemented in conjunction with enterprise software, such as a manufacturing application, a planning application, a relationship management application, and a middleware application or platform. Additionally, the illustrative embodiments may be implemented in conjunction with a hardware component, such as in a firmware, as embedded software in a hardware device, or in any other suitable hardware or software form. 
     Any advantages listed herein are only exemplary and are not intended to be limiting on the illustrative embodiments. Additional advantages may be realized by specific illustrative embodiments. Furthermore, a particular illustrative embodiment may have some, all, or none of the advantages listed above. 
     With reference to the figures and in particular with reference to  FIGS. 1 and 2 , these figures are exemplary diagrams of data processing environments in which illustrative embodiments may be implemented.  FIGS. 1 and 2  are only exemplary and are not intended to assert or imply any limitation with regard to the environments in which different embodiments may be implemented. A particular implementation may make many modifications to the depicted environments based on the following description. 
       FIG. 1  depicts a pictorial representation of a network of data processing systems in which illustrative embodiments may be implemented. Data processing environment  100  is a network of computers in which the illustrative embodiments may be implemented. Data processing environment  100  includes network  102 . Network  102  is the medium used to provide communications links between various devices and computers connected together within data processing environment  100 . Network  102  may include connections, such as wire, wireless communication links, or fiber optic cables. 
     Software applications may execute on any computer in data processing environment  100 . Server  104  and server  106  couple to network  102  along with storage unit  108 . In the depicted example, server  106  includes directory  105 , which may be an exemplary software application executing on server  106 , in conjunction with which the illustrative embodiments may be implemented. In addition, clients  110 ,  112 , and  114  couple to network  102 . Servers  104  and  106 , storage units  108 , and clients  110 ,  112 , and  114  may couple to network  102  using wired connections, wireless communication protocols, or other suitable data connectivity. Clients  110 ,  112 , and  114  may be, for example, personal computers or network computers. 
     In the depicted example, server  104  provides data, such as boot files, operating system images, and applications to clients  110 ,  112 , and  114 . Clients  110 ,  112 , and  114  are clients to server  104  in this example. Data processing environment  100  may include additional servers, clients, and other devices that are not shown. 
     In the depicted example, data processing environment  100  may be the Internet. Network  102  may represent a collection of networks and gateways that use the Transmission Control Protocol/Internet Protocol (TCP/IP) and other protocols to communicate with one another. At the heart of the Internet is a backbone of data communication links between major nodes or host computers, including thousands of commercial, governmental, educational, and other computer systems that route data and messages. Of course, data processing environment  100  also may be implemented as a number of different types of networks, such as for example, an intranet, a local area network (LAN), or a wide area network (WAN).  FIG. 1  is intended as an example, and not as an architectural limitation for the different illustrative embodiments. 
     Among other uses, data processing environment  100  may be used for implementing a client server environment in which the illustrative embodiments may be implemented. A client server environment enables software applications and data to be distributed across a network such that an application functions by using the interactivity between a client data processing system and a server data processing system. 
     With reference to  FIG. 2 , this figure depicts a block diagram of a data processing system in which illustrative embodiments may be implemented. Data processing system  200  is an example of a computer, such as server  104  or client  110  in  FIG. 1 , in which computer usable program code or instructions implementing the processes may be located for the illustrative embodiments. 
     In the depicted example, data processing system  200  employs a hub architecture including north bridge and memory controller hub (NB/MCH)  202  and south bridge and input/output (I/O) controller hub (SB/ICH)  204 . Processing unit  206 , main memory  208 , and graphics processor  210  are coupled to north bridge and memory controller hub (NB/MCH)  202 . Processing unit  206  may contain one or more processors and may be implemented using one or more heterogeneous processor systems. Graphics processor  210  may be coupled to the NB/MCH through an accelerated graphics port (AGP) in certain implementations. 
     In the depicted example, local area network (LAN) adapter  212  is coupled to south bridge and I/O controller hub (SB/ICH)  204 . Audio adapter  216 , keyboard and mouse adapter  220 , modem  222 , read only memory (ROM)  224 , universal serial bus (USB) and other ports  232 , and PCI/PCIe devices  234  are coupled to south bridge and I/O controller hub  204  through bus  238 . Hard disk drive (HDD)  226  and CD-ROM  230  are coupled to south bridge and I/O controller hub  204  through bus  240 . PCI/PCIe devices may include, for example, Ethernet adapters, add-in cards, and PC cards for notebook computers. PCI uses a card bus controller, while PCIe does not. ROM  224  may be, for example, a flash binary input/output system (BIOS). Hard disk drive  226  and CD-ROM  230  may use, for example, an integrated drive electronics (IDE) or serial advanced technology attachment (SATA) interface. A super I/O (SIO) device  236  may be coupled to south bridge and I/O controller hub (SB/ICH)  204 . 
     An operating system runs on processing unit  206 . The operating system coordinates and provides control of various components within data processing system  200  in  FIG. 2 . The operating system may be a commercially available operating system such as Microsoft® Windows® XP (Microsoft and Windows are trademarks of Microsoft Corporation in the United States and other countries). An object oriented programming system, such as the Java™ programming system, may run in conjunction with the operating system and provides calls to the operating system from Java™ programs or applications executing on data processing system  200  (Java is a trademark of Sun Microsystems, Inc., in the United States and other countries). 
     Instructions for the operating system, the object-oriented programming system, and applications or programs are located on storage devices, such as hard disk drive  226 , and may be loaded into main memory  208  for execution by processing unit  206 . The processes of the illustrative embodiments may be performed by processing unit  206  using computer implemented instructions, which may be located in a memory, such as, for example, main memory  208 , read only memory  224 , or in one or more peripheral devices. 
     The hardware in  FIGS. 1-2  may vary depending on the implementation. Other internal hardware or peripheral devices, such as flash memory, equivalent non-volatile memory, or optical disk drives and the like, may be used in addition to or in place of the hardware depicted in  FIGS. 1-2 . In addition, the processes of the illustrative embodiments may be applied to a multiprocessor data processing system. 
     In some illustrative examples, data processing system  200  may be a personal digital assistant (PDA), which is generally configured with flash memory to provide non-volatile memory for storing operating system files and/or user-generated data. A bus system may comprise one or more buses, such as a system bus, an I/O bus, and a PCI bus. Of course, the bus system may be implemented using any type of communications fabric or architecture that provides for a transfer of data between different components or devices attached to the fabric or architecture. 
     A communications unit may include one or more devices used to transmit and receive data, such as a modem or a network adapter. A memory may be, for example, main memory  208  or a cache, such as the cache found in north bridge and memory controller hub  202 . A processing unit may include one or more processors or CPUs. 
     The depicted examples in  FIGS. 1-2  and above-described examples are not meant to imply architectural limitations. For example, data processing system  200  also may be a tablet computer, laptop computer, or telephone device in addition to taking the form of a PDA. 
     With reference to  FIG. 3 , this figure depicts a block diagram of an application using memory in accordance with an illustrative embodiment. Application  300  is an exemplary application executing in data processing system  302 . Directory  105  in  FIG. 1  is an example of application  300 . Data processing system  302  may be implemented using server  106  in  FIG. 1 . 
     Application  300  may include component  304 , which may include application programming interface (API), tools, toolkits, functions, and other features of application  300  that a user may use for interacting with application  300 . For example, application  300  may include a set of APIs that may allow a user to extend the functionality of application  300  by adding code to the code of application  300 . For example, if application  300  were a directory server, component  304  of the directory server may be used to create an extended operation that may perform certain custom functions with respect to the directory server. 
     Application  300  may also include graphical user interface (GUI) component  306  that may allow a user to interact with application  300  using a graphical user interface, such as with a web browser. 
     Memory  308  may be associated with data processing system  302 . Memory  308  may be implemented using main memory  208  in  FIG. 2 . Application  300  may use memory  308  for performing the functions of application  300  as well as any functions that may be added to application  300  using component  304 . A memory management system associated with data processing system  302  may allocate memory space from memory  308  to application  300 , and application  300  may free an allocated memory space in memory  308  when not using such memory space. If application  300  has a memory leak, application  300  may not free a portion of the memory space in memory  308  that may be allocated to application  300 . 
     Application  300  may also have access to data storage  310 . Data storage  310  may be another data storage, such as a hard disk, a flash drive, additional random access memory (RAM), RAM elsewhere in the data processing system, a network storage, tape medium, CD-ROM, CD-RAM, or any other form of data storage suitable for a particular implementation. Application  300  may use space in data storage  310  to save data, such as user information, log files, and code. 
     With reference to  FIG. 4 , this figure depicts a block diagram of on-demand monitoring of memory usage in accordance with an illustrative embodiment. Application  400  is an exemplary application executing in data processing system  402 . Application  400  may be analogous to application  300  in  FIG. 3 . Data processing system  402  may be implemented using data processing system  302  in  FIG. 3 . 
     Component  404  including APIs, tools, and functions for application  400 , and graphical user interface component  406  correspond to component  304  and graphical user interface component  306  in  FIG. 3 . Application  400  interacts with memory  408  and data storage  410  in a manner analogous to application  300 &#39;s interaction with memory  308  and data storage  310  in  FIG. 3 . 
     Memory monitoring program  412  according to the illustrative embodiment includes a function that monitors the memory being allocated to application  400  and being freed by application  400 . In one embodiment, memory monitoring program  412  may be implemented as a software application that may be associated with application  400  using APIs in component  404 . For example, if application  400  were a directory server, memory monitoring program  412  may be an extended operation associated with the directory server. A user may trigger the extended operation on-demand during the execution of the directory server. On-demand triggering is the turning on, turning off, or otherwise controlling a function, such as memory monitoring program  412 , as and when a user or a system desires. 
     In another embodiment, memory monitoring program  412  may include code that may be separate from but may be executed on-demand with respect to application  400 . For example, memory monitoring program  412  may be a software application that application  400  may be able to trigger during the execution of application  400  as determined by logic within application  400 , memory monitoring program  412 , or both. In such an embodiment, memory monitoring program  412  as software application may be integrated with, or separate from, application  400 . 
     As an example, a user may trigger memory monitoring program  412  into operation, such as by sending a command to memory monitoring program  412  to turn on memory usage monitoring, when the user suspects a memory leak. As another example, application  400  may itself trigger memory monitoring program  412 , when certain logic in application  400  detects a memory leak in application  400 . As another example, data processing system  402  may trigger memory monitoring program  412  when certain logic executing in data processing system  402  suspects a memory leak. As another example, logic within memory monitoring program  412  may identify an indicator of a memory leak and trigger the on-demand monitoring. 
     For example, a logic executing in a data processing system may determine that an amount of memory allocated to an application is increasing over time, triggering the suspicion of a memory leak. As another example, a logic in a data processing system may determine that the overall performance of the data processing system deteriorates over a period of time when an application executes over that period of time. As another example, a logic in an application may determine that the performance of the application deteriorates over a period of time when the application executes over that period of time. As another example, a logic in the memory monitoring program may determine that an associated application has an amount of memory allocated to the application that the application has not used for a preset period of time. 
     As another example, a logic in a data processing system, an application, or a memory monitoring program according to the illustrative embodiments may measure a rate of the growth of the allocated memory and suspect a memory leak if the rate exceeds a certain threshold value. As another example, a similarly situated logic may trigger a mechanism for freeing allocated but unused memory, called garbage collection, in conjunction with measuring a rate of growth of allocated memory, and measure a drop in the amount of allocated memory after garbage collection. Such a logic may determine that a memory leak may exist if the amount of unused allocated memory freed after garbage collection is above a threshold value. 
     The methods and considerations for determining or indicating a memory leak as described above are only exemplary and not limiting on the illustrative embodiments. Many other considerations and logic configurations for determining, identifying, indicating, or suspecting a memory leak in specific implementations will be apparent from this disclosure and the same are contemplated within the scope of the illustrative embodiments. Furthermore, any logic for determining, identifying, indicating, or suspecting a memory leak may be included in a data processing system, an application, or a memory monitoring program according to the illustrative embodiments, to operate as described with respect to memory monitoring program  412 . 
     Once the user or a system determines that sufficient monitoring of memory usage has occurred, they may trigger memory monitoring program  412  to stop. The user or a system may also trigger memory monitoring program  412  to perform another operation, such as dump the monitoring data to a file. Dumping the data is the process of recording the data, such as for example, recording in a file on hard disk, tape drive, in database, or in any other form. 
     Some more examples of the operations that a user or a system may trigger may be transmitting the monitoring data to another data processing system, scheduling another monitoring at a different time, or adjusting the parameters of monitoring. For example, the user or system may trigger memory monitoring program  412  to adjust the duration or frequency of monitoring the memory usage, or adjust the address space of the memory to be monitored. 
     In operation, memory monitoring program  412  may itself use a portion of memory  408 , such as memory space  414 , for maintaining the monitoring data. For example, memory monitoring program  412  may maintain a list of memory addresses allocated to application  400  in memory space  414 . Memory monitoring program  412  may remove memory addresses of freed memory from such a list as application frees allocated memory space. When memory monitoring program  412  is instructed to stop the monitoring, the list of memory addresses remaining in memory space  414  may indicate the memory space that application  400  failed to free during the course of monitoring. 
     In operation, memory monitoring program  412  may also use a portion of data storage  410 , such as storage space  416 . For example, memory monitoring program  412  may periodically dump the monitoring data from memory space  414  to storage space  416  so that memory monitoring program  412  may continue monitoring. As another example, a user or system may trigger memory monitoring program  412  to dump the monitoring data to storage space  416 , which may include a log file. As another example, if memory monitoring program  412  determines that an event during the monitoring may be of particular interest to a user or system, memory monitoring program  412  may write that information in storage space  416  so that another application, such as a notification application, may pick up the information and deliver to the user or system. 
     The operations and functions described with respect to memory monitoring program  412  are only exemplary and described here for the clarity of the illustrative embodiments. Many other operations and functions may be configured and triggered in memory monitoring program  412  without departing from the scope of the illustrative embodiments. 
     With reference to  FIG. 5 , this figure depicts a block diagram of triggering a memory monitoring program in accordance with an illustrative embodiment. Memory monitoring program  502  may execute in association with application  504  in a data processing system, such as server  506 . Memory monitoring program  502  may be similar to memory monitoring program  412  in  FIG. 4 . Server  506  and server  508  may be similar to server  104  and server  106  in  FIG. 1 . Client  510  and client  512  may each be similar to any of client  110 ,  112 , or  114  in  FIG. 1 . Server  506 , server  508 , client  510 , and client  512  may be data processing systems distributed across a data processing environment and interconnected using network  514  in the manner of  FIG. 1 . 
     Any of server  506 , server  508 , client  510 , and client  512 , or a user thereon, may trigger an operation of memory monitoring program  502  by sending a command to memory monitoring program  502 . For example, administration application  516  may be a network administration application that may monitor the performance of the various data processing systems communicating over network  514 . Administration application  516  may detect a degradation of the performance of server  506  and may suspect application  504  of having a memory leak. Administration application  516  may trigger an operation on memory monitoring program  504  by sending command  518  to memory monitoring program  502  over network  514 . In implementing the illustrative embodiments, applications similar to administration application  516  may be made aware of the existence of a capability for on-demand monitoring of memory usage existing in memory monitoring program  502 . 
     Alternatively, a user using client application  520  on client  510  may trigger an operation, such as on-demand monitoring of memory usage by application  504 , by sending command  522  to memory monitoring program  502 . The user may also send command  522 , which may be a command to stop the monitoring started by command  518 , or vice versa. Alternatively, a user on client  512  may use command prompt  524  to issue command  526  to trigger an operation of memory monitoring program  502 . 
     The various commands and the methods of sending those commands to memory monitoring program  502  are described here only as exemplary. A particular implementation of the illustrative embodiments may implement these and other commands in the form described or other forms without departing from the scope of the illustrative embodiments. For example, in one embodiment, only the issuer of the command to start a memory monitoring may be allowed to stop the monitoring. In another embodiment, any authorized system, application, or user may start, stop, pause, or modify a memory monitoring operation of memory monitoring program  502 . 
     In another embodiment, the various commands to trigger operations on memory monitoring program  502  may be issued using a command prompt, a graphical user interface, a function call, a message, or a combination thereof. Furthermore, such commands may be communicated to memory monitoring program  502  that may be located within the command issuing data processing system or across a data network. 
     With reference to  FIG. 6 , this figure depicts a block diagram of an exemplary manner of sending commands to a memory monitoring program in accordance with an illustrative embodiment. A user may use command prompt  602  to issue one or more commands  604  to memory monitoring program  606 . Commands  604  may be, for example, to begin or end memory usage monitoring, or to dump the data from a monitoring session to a file, such as file  608 . Memory monitoring program  606  may be associated with application  610  whose memory usage is to be monitored. For example, memory monitoring program  606  may be an extended operation of a lightweight directory access protocol (LDAP) server, which may be an exemplary application  610 , whose memory usage a user wishes to monitor without disrupting the operation of the directory. 
     With reference to  FIG. 7 , this figure depicts a block diagram of another exemplary manner of sending commands to a memory monitoring program in accordance with an illustrative embodiment. A user may use graphical user interface  702  to issue one or more graphical inputs  704  that graphical user interface component  706  associated with application  708  may receive. Application  708  may be an application whose memory usage the user wishes to monitor. Graphical user interface  706  may translate graphical inputs  704  into commands  710  and send commands  710  to memory monitoring program  712 . Commands  710  may be, for example, commands to begin or end memory usage monitoring, or commands to dump the data from a monitoring session, such as to file  714  or other form of storing or communicating data. For example, a user may click a uniform resource locator (URL) link on a web page using a web browser to send graphical inputs  704 , which memory monitoring program  712  receives as commands  710 . 
     With reference to  FIG. 8 , this figure depicts a flowchart of a process of instructing a memory monitoring program in accordance with an illustrative embodiment. Process  800  may be implemented in a memory monitoring program, such as memory monitoring program  502  in  FIG. 5 , or  606  in  FIG. 6 , or  712  in  FIG. 7 . 
     Process  800  begins by receiving a command (step  802 ). Process  800  may authenticate the user, system, or application that issued the command (step  804 ). Process  800  determines whether the issuer of the command is authenticated (step  806 ). If the issuer of the command is authenticated and authorized to issue the command (“Yes” path of step  806 ), process  800  executes the command (step  808 ). If the issuer of the command is not authenticated or not authorized to execute the command (“No” path of step  806 ), process  800  rejects the command received in step  802  (step  810 ). For example, a user may be authenticated as being a valid user on a system, but the user may not be authorized to issue a particular command. 
     A particular implementation may omit steps  804  and  806  without departing from the scope of the illustrative embodiments. When omitting authentication and authorization steps  804  and  806 , the implementation may proceed from step  802  to step  808 , accepting all commands that process  800  receives in step  802 . 
     Process  800  may notify about executing or rejecting a command (step  812 ). For example, process  800  may send an email to a system administrator if an unauthorized user or application attempted to start memory monitoring. As another example, process  800  may make an entry in a log file for a command that process  800  executes. Many other ways of notifying users and systems will become apparent from this disclosure. Process  800  ends thereafter. 
     With reference to  FIG. 9 , this figure depicts a flowchart of a process of on-demand monitoring of memory usage in accordance with an illustrative embodiment. Process  900  may be implemented using a memory monitoring program, such as memory monitoring program  502  in  FIG. 5 , or  606  in  FIG. 6 , or  712  in  FIG. 7 . Process  900  may be used in conjunction with an application when the application is suspected of having a memory leak. 
     Process  900  begins by receiving a command to begin monitoring the memory usage of an associated application (step  902 ). In one embodiment, process  900  may perform a step of determining, identifying, indicating, or suspecting a memory leak in the associated application, as exemplarily described with respect to  FIG. 4 . In such an embodiment, process  900  may perform step  902  upon making such a determination, identification, indication, or suspicion. 
     Process  900  begins monitoring the memory usage of the application (step  904 ). A command to begin monitoring the memory usage may include a set of other parameters, such as, for example, a time at which the monitoring should begin, or an address range that is to be monitored, or processes or threads whose memory usage is to be monitored. A set of parameters is zero or more parameters. Many other parameters may be included with the command to begin the monitoring without departing from the scope of the illustrative embodiment. 
     Monitoring the memory usage may include monitoring the calling stack. A command for monitoring the memory usage may include commands or parameters for monitoring the calling stack. A calling stack is a record of which functions, subroutines, or set of instructions of an application are active at a given time. An active function, subroutine, or a set of instruction is a function, subroutine, or a set of instruction that has started executing but has not finished executing. The calling stack provides information about where the program control should return when the active function, subroutine, or the set of instruction finishes executing. The memory usage monitored in this manner may give additional information about the memory that is still allocated to the application and has not been freed. 
     Process  900  receives a command to dump the monitoring data, for example, into a file (step  906 ). Process  900  dumps the monitoring data according to the command received in step  906  (step  908 ). A command to dump the monitoring data may include a set of additional parameters, such as, for example, when to dump the data, how much data to dump, which process&#39; or thread&#39;s data to dump, and whether to erase the dumped data from memory. Many other parameters may be included with the command to dump the monitoring data without departing from the scope of the illustrative embodiment. 
     Process  900  receives a command to end monitoring the memory usage of an associated application (step  910 ). Process  900  ends monitoring the memory usage of the application (step  912 ). Process  900  ends thereafter. A command to end monitoring the memory usage may include a set of other parameters, such as, for example, a time at which the monitoring should end, or an address range for which the monitoring is to end, or processes or threads whose memory usage monitoring is to end. Many other parameters may be included with the command to end the monitoring without departing from the scope of the illustrative embodiment. 
     The components in the block diagrams and the steps in the flowcharts described above are described only as exemplary. The components and the steps have been selected for the clarity of the description and are not limiting on the illustrative embodiments. For example, a particular implementation may combine, omit, further subdivide, modify, augment, reduce, or implement alternatively, any of the components or steps without departing from the scope of the illustrative embodiments. Furthermore, the steps of the processes described above may be performed in a different order within the scope of the illustrative embodiments. 
     Thus, a computer implemented method, apparatus, and computer program product are provided in the illustrative embodiments for on-demand monitoring of memory usage. By implementing the illustrative embodiments, a user may be able to monitor the memory usage of an application, or a part thereof, that the user suspects of having a memory leak. The user may monitor the memory usage for memory leaks using the illustrative embodiments without having to shutdown the all or part of the application. Users may also not need to recompile the code of the application in order to determine a cause of the memory leak. 
     Using the illustrative embodiments may allow the user to investigate a memory leak in running applications without interrupting business-critical operations, such as in production environments. The illustrative embodiments also allow the user to start, stop, or modify the monitoring on demand, to with, as needed, in the actual environment in which the user suspects a memory leak. Thus, the user may not have to replicate the circumstances in a lab environment in an attempt to recreate the memory leak. 
     Furthermore, using the memory usage data collected by the illustrative embodiments, a user may be able to identify precisely which function, subroutine, instruction, command, operation, or step in an application&#39;s code may include the memory leak. For example, illustrative embodiments may collect the data such that the data includes an identifier of an instruction requesting memory allocation and the address of the memory allocated in response. If that allocated memory is not freed when no longer in use, the data resulting from the illustrative embodiments will provide the information that may assist a user in locating the cause of the memory leak, to wit, the instruction in this example. Used in this manner, the illustrative embodiments may provide an address of the memory not freed, a size of the memory not freed, and an identification of an instruction in the application that had allocated that memory. Thus, the illustrative embodiments may assist the user in locating or even pinpointing the cause of a memory leak in an application without having to debug the application or recreate the memory leak circumstances. 
     The invention can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment containing both hardware and software elements. In a preferred embodiment, the invention is implemented in software, which includes but is not limited to firmware, resident software, and microcode. 
     Furthermore, the invention can take the form of a computer program product accessible from a computer-usable or computer-readable storage device providing program code for use by or in connection with a computer or any instruction execution system. For the purposes of this description, a computer-usable or computer-readable storage device can be any tangible apparatus that can contain, or store, the program for use by or in connection with the instruction execution system, apparatus, or device. 
     The storage device can be an electronic, magnetic, optical, electromagnetic, or semiconductor system (or apparatus or device) or a propagation medium. Examples of a computer-readable storage device include a semiconductor or solid state memory, magnetic tape, a removable computer diskette, a random access memory (RAM), a read-only memory (ROM), a rigid magnetic disk, and an optical disk. Current examples of optical disks include compact disk-read only memory (CD-ROM), compact disk-read/write (CD-R/W) and DVD. The terms “computer usable storage device” and “storage device” do not encompass a signal propagation medium or a transmission medium, any description in this disclosure to the contrary notwithstanding. 
     Further, a computer storage medium may contain or store a computer-readable program code such that when the computer-readable program code is executed on a computer, the execution of this computer-readable program code causes the computer to transmit another computer-readable program code over a communications link. This communications link may use a medium that is, for example without limitation, physical or wireless. 
     A data processing system suitable for storing and/or executing program code will include at least one processor coupled directly or indirectly to memory elements through a system bus. The memory elements can include local memory employed during actual execution of the program code, bulk storage, and cache memories, which provide temporary storage of at least some program code in order to reduce the number of times code must be retrieved from bulk storage during execution. 
     A data processing system may act as a server data processing system or a client data processing system. Server and client data processing systems may include data storage media that are computer usable, such as being computer readable. A data storage medium associated with a server data processing system may contain computer usable code. A client data processing system may download that computer usable code, such as for storing on a data storage medium associated with the client data processing system, or for using in the client data processing system. The server data processing system may similarly upload computer usable code from the client data processing system. The computer usable code resulting from a computer usable program product embodiment of the illustrative embodiments may be uploaded or downloaded using server and client data processing systems in this manner. 
     Input/output or I/O devices (including but not limited to keyboards, displays, pointing devices, etc.) can be coupled to the system either directly or through intervening I/O controllers. 
     Network adapters may also be coupled to the system to enable the data processing system to become coupled to other data processing systems or remote printers or storage devices through intervening private or public networks. Modems, cable modem and Ethernet cards are just a few of the currently available types of network adapters. 
     The description of the present invention has been presented for purposes of illustration and description, and is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiment was chosen and described in order to explain the principles of the invention, the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated.