Setting Resource Controls

How to Set the Maximum Number of LWPs for Each Task in a Project

This procedure adds a project named x-files to the /etc/project file and sets a maximum number of LWPs for a task created in the project.

1. Become root or assume an equivalent role.
2. Use the projadd command with the -K option to create a project called x-files. Set the maximum number of LWPs for each task created in the project to 3.

   # projadd -K 'task.max-lwps=(privileged,3,deny)' x-files

3. View the entry in the /etc/project file by using one of the following methods:

   • Type:

     # projects -l
     system
             projid : 0
             comment: ""
             users  : (none)
             groups : (none)
             attribs: 
     .
     .
     .
     x-files
             projid : 100
             comment: ""
             users  : (none)
             groups : (none)
             attribs: task.max-lwps=(privileged,3,deny)

   • Type:

     # cat /etc/project
     system:0:System:::
     .
     .
     .
     x-files:100::::task.max-lwps=(privileged,3,deny)

Example 7-1 Sample Session

After implementing the steps in this procedure, when the root user creates a new task in project x-files by joining the project with newtask, the user will not be able to create more than three LWPs while running in this task. This is shown in the following annotated sample session.

# newtask -p x-files csh

# prctl -n task.max-lwps $$
process: 111107: csh
NAME    PRIVILEGE    VALUE    FLAG   ACTION            RECIPIENT
task.max-lwps
        usage            3
        privileged       3       -   deny                      -
        system       2.15G     max   deny                      -
# id -p
uid=0(root) gid=1(other) projid=100(x-files)

# ps -o project,taskid -p $$
 PROJECT TASKID
 x-files    73

# csh        /* creates second LWP */

# csh        /* creates third LWP */

# csh        /* cannot create more LWPs */
Vfork failed
#

How to Set Multiple Controls on a Project

The /etc/project file can contain settings for multiple resource controls for each project as well as multiple threshold values for each control. Threshold values are defined in action clauses, which are comma-separated for multiple values.

1. Become root or assume an equivalent role.
2. Use the projmod command with the -s and -K options to set resource controls on project x-files:

   # projmod -s -K 'task.max-lwps=(basic,10,none),(privileged,500,deny);
   process.max-file-descriptor=(basic,128,deny)' x-filesone line in file

   The following controls are set:

   • A basic control with no action on the maximum LWPs per task.

   • A privileged deny control on the maximum LWPs per task. This control causes any LWP creation that exceeds the maximum to fail, as shown in the previous example How to Set the Maximum Number of LWPs for Each Task in a Project.

   • A limit on the maximum file descriptors per process at the basic level, which forces the failure of any open call that exceeds the maximum.

3. View the entry in the file by using one of the following methods:

   • Type:

     # projects -l
     .
     .
     .
     x-files
             projid : 100
             comment: ""
             users  : (none)
             groups : (none)
             attribs: process.max-file-descriptor=(basic,128,deny)
                      task.max-lwps=(basic,10,none),(privileged,500,deny) one line in file

   • Type:

     # cat /etc/project
     .
     .
     .
     x-files:100::::process.max-file-descriptor=(basic,128,deny);
     task.max-lwps=(basic,10,none),(privileged,500,deny) one line in file