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Posted 1 Mar 2007


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How to Set the Maximum Memory a Process can Use at the OS Level

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1 Mar 2007CPOL2 min read
Describes how to use WIN32 methods, and the concepts of Jobs to set a hard limit on the amount of memory a process can use. Also, provides a C# wrapper around the PInvoke calls.


It is not a common requirement, but I ran into a scenario where I needed to set a hard Operating System limit on the maximum amount of memory a process could use. The Process.MaxWorkingSet property is, from what I can gather, merely a suggestion and easily worked-around by the Process.

This article describes the general approach to setting a hard limit to the memory a process can use and provides a link with running code to do so.


Windows has the concept of Job Objects, allowing management of system resources at an OS level, such as CPU or memory requirements.

To set a hard memory limit, the process is simple:

  1. Create a Job object using CreateJobObject
  2. Use the SetInformationJobObject method to set the various process limits and controls, such as memory
  3. Finally, assign a running process to the Job with AssignProcessToJob and it will automatically be held to the limits of the associated Job.

This code is demonstrated in the PublicDomain package in the following method:

    (uint minWorkingSetSize, uint maxWorkingSetSize, params Process[] processesToLimit)

This allows you to pass the min/max memory limits and a list of running Processes to apply the limit to.

You can watch the memory rise in task manager and hit the maximum that you set, subsequently throwing OutOfMemory Exceptions (if the GC can't reclaim enough needed memory).

The code returns a C# Job object which is a light wrapper around the handle returned by the WIN32 CreateJobObject method. The C# class also implements IDisposable, and once the Job is disposed, the memory limits are removed:

using (Process p = new Process())
    p.StartInfo = new ProcessStartInfo("myexe.exe");

    using (PublicDomain.Win32.Job j = PublicDomain.Win32.Job.CreateJobWithMemoryLimits(
        (uint)GlobalConstants.BytesInAMegabyte * 12,
        (uint)GlobalConstants.BytesInAMegabyte * 30,
        // As long as the Job object j is alive, there
        // will be a memory limit of 30 Mb on the Process p


The PublicDomain package is a completely free, public domain collection of oft-needed code and packages for .NET. There is no license, so the code (or any part of it) may be included even in corporate applications. Public domain code has no authority.


  • 1st March, 2007: Initial post


This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)


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Comments and Discussions

Questionis this working on windows8 64 bit? Pin
AnandChavali3-May-14 22:01
MemberAnandChavali3-May-14 22:01 
AnswerNot True Pin
rvanchis28-Apr-09 20:35
Memberrvanchis28-Apr-09 20:35 
GeneralRe: Not True Pin
schizoidboy6-May-09 5:23
Memberschizoidboy6-May-09 5:23 
AnswerRe: Not True Pin
rvanchis6-May-09 5:55
Memberrvanchis6-May-09 5:55 
Questionhow to use IDisposable Pin
Oren Rosen20-Apr-09 6:07
MemberOren Rosen20-Apr-09 6:07 
AnswerRe: how to use IDisposable Pin
schizoidboy20-Apr-09 9:47
Memberschizoidboy20-Apr-09 9:47 
GeneralRe: how to use IDisposable Pin
Oren Rosen20-Apr-09 10:47
MemberOren Rosen20-Apr-09 10:47 
GeneralRe: how to use IDisposable Pin
schizoidboy20-Apr-09 11:25
Memberschizoidboy20-Apr-09 11:25 
GeneralRe: how to use IDisposable Pin
Oren Rosen20-Apr-09 18:24
MemberOren Rosen20-Apr-09 18:24 
GeneralRe: how to use IDisposable Pin
schizoidboy21-Apr-09 4:41
Memberschizoidboy21-Apr-09 4:41 
GeneralRe: how to use IDisposable Pin
schizoidboy21-Apr-09 4:43
Memberschizoidboy21-Apr-09 4:43 
GeneralRe: how to use IDisposable Pin
Oren Rosen21-Apr-09 9:11
MemberOren Rosen21-Apr-09 9:11 
GeneralRe: how to use IDisposable Pin
schizoidboy21-Apr-09 14:25
Memberschizoidboy21-Apr-09 14:25 
GeneralRe: how to use IDisposable Pin
Oren Rosen21-Apr-09 19:35
MemberOren Rosen21-Apr-09 19:35 
1. -i opened TM (task manager). started the code and monitored app.
-in TM the app working set was more the 60mb.
-after running ChangeLimits() with max set to 30mb, in TM the app working set limited to 30mb.
-when running RemoveLimits() there was no change to the app working set.
-when running Change limits() with new max set to 40mb there was no change to the app working set and an access denied exception was thrown.
-when running a second app and running ChangeLimits() again, i get access denied exception for the first app (then one with the 30mb limit) and the second app working set was limited to 30mb.

when running the code in debug mode, you can see the m_handle value saved by m_job when creating the job is disposed when running RemoveLimits().
if that does not work, how will i be able to remove the limits?


GeneralRe: how to use IDisposable Pin
Oren Rosen22-Apr-09 1:06
MemberOren Rosen22-Apr-09 1:06 
GeneralAccess is denied Error Pin
craigclark77710-Sep-08 7:33
Membercraigclark77710-Sep-08 7:33 
GeneralRe: Access is denied Error Pin
schizoidboy13-Sep-08 15:06
Memberschizoidboy13-Sep-08 15:06 
QuestionMaximum limit? Pin
Todd Smith1-Mar-07 8:02
MemberTodd Smith1-Mar-07 8:02 
AnswerRe: Maximum limit? Pin
Robert Rohde2-Mar-07 2:22
MemberRobert Rohde2-Mar-07 2:22 
AnswerRe: Maximum limit? Pin
The_Mega_ZZTer15-Nov-07 9:34
MemberThe_Mega_ZZTer15-Nov-07 9:34 

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