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System Administration Guide: Virtualization Using the Solaris Operating System
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Using the prctl Command

Use the prctl command to make runtime interrogations of and modifications to the resource controls associated with an active process, task, or project on the system. See the prctl(1) man page for more information.

How to Use the prctl Command to Display Default Resource Control Values

This procedure must be used on a system on which no resource controls have been set or changed. There can be only non-default entries in the /etc/system file or in the project database.

  • Use the prctl command on any process, such as the current shell that is running.
    # prctl $$
    process: 100337: -sh
    NAME    PRIVILEGE       VALUE    FLAG   ACTION                   RECIPIENT
    process.max-port-events
            privileged      65.5K       -   deny                             -
            system          2.15G     max   deny                             -
    process.crypto-buffer-limit
            system          16.0EB    max   deny                             -
    process.max-crypto-sessions
            system          18.4E     max   deny                             -
    process.add-crypto-sessions
            privileged        100       -   deny                             -
            system          18.4E     max   deny                             -
    process.min-crypto-sessions
            privileged         20       -   deny                             -
            system          18.4E     max   deny                             -
    process.max-msg-messages
            privileged      8.19K       -   deny                             -
            system          4.29G     max   deny                             -
    process.max-msg-qbytes
            privileged      64.0KB      -   deny                             -
            system          16.0EB    max   deny                             -
    process.max-sem-ops
            privileged        512       -   deny                             -
            system          2.15G     max   deny                             -
    process.max-sem-nsems
            privileged        512       -   deny                             -
            system          32.8K     max   deny                             -
    process.max-address-space
            privileged      16.0EB    max   deny                             -
            system          16.0EB    max   deny                             -
    process.max-file-descriptor
            basic             256       -   deny                        100337
            privileged      65.5K       -   deny                             -
            system          2.15G     max   deny                             -
    process.max-core-size
            privileged      8.00EB    max   deny                             -
            system          8.00EB    max   deny                             -
    process.max-stack-size
            basic           8.00MB      -   deny                        100337
            privileged      8.00EB      -   deny                             -
            system          8.00EB    max   deny                             -
    process.max-data-size
            privileged      16.0EB    max   deny                             -
            system          16.0EB    max   deny                             -
    process.max-file-size
            privileged      8.00EB    max   deny,signal=XFSZ                 -
            system          8.00EB    max   deny                             -
    process.max-cpu-time
            privileged      18.4Es    inf   signal=XCPU                      -
            system          18.4Es    inf   none                             -
    task.max-cpu-time
            system          18.4Es    inf   none                             -
    task.max-lwps
            system          2.15G     max   deny                             -
    project.max-contracts
            privileged      10.0K       -   deny                             -
            system          2.15G     max   deny                             -
    project.max-device-locked-memory
            privileged       499MB      -   deny                             -
            system          16.0EB    max   deny                             -
    project.max-port-ids
            privileged      8.19K       -   deny                             -
            system          65.5K     max   deny                             -
    project.max-shm-memory
            privileged      1.95GB      -   deny                             -
            system          16.0EB    max   deny                             -
    project.max-shm-ids
            privileged        128       -   deny                             -
            system          16.8M     max   deny                             -
    project.max-msg-ids
            privileged        128       -   deny                             -
            system          16.8M     max   deny                             -
    project.max-sem-ids
            privileged        128       -   deny                             -
            system          16.8M     max   deny                             -
    project.max-tasks
            system          2.15G     max   deny                             -
    project.max-lwps
            system          2.15G     max   deny                             -
    project.cpu-shares
            privileged          1       -   none                             -
            system          65.5K     max   none                             -
    zone.max-lwps
            system          2.15G     max   deny                             -
    zone.cpu-shares
            privileged          1       -   none                             -
            system          65.5K     max   none                             -

How to Use the prctl Command to Display Information for a Given Resource Control

  • Display the maximum file descriptor for the current shell that is running.
    # prctl -n process.max-file-descriptor $$
    process: 110453: -sh
    NAME    PRIVILEGE       VALUE    FLAG   ACTION       RECIPIENT
    process.max-file-descriptor
            basic             256       -   deny            110453
            privileged      65.5K       -   deny                 -
            system          2.15G     max   deny     

How to Use prctl to Temporarily Change a Value

This example procedure uses the prctl command to temporarily add a new privileged value to deny the use of more than three LWPs per project for the x-files project. The result is comparable to the result in How to Set the Maximum Number of LWPs for Each Task in a Project.

  1. Become superuser or assume an equivalent role.

    Roles contain authorizations and privileged commands. For more information about roles, see Using the Solaris Management Tools With RBAC (Task Map) in System Administration Guide: Basic Administration.

  2. Use newtask to join the x-files project.
    # newtask -p x-files
  3. Use the id command with the -p option to verify that the correct project has been joined.
    # id -p
    uid=0(root) gid=1(other) projid=101(x-files)
  4. Add a new privileged value for project.max-lwps that limits the number of LWPs to three.
    # prctl -n project.max-lwps -t privileged -v 3 -e deny -i project x-files
  5. Verify the result.
    # prctl -n project.max-lwps -i project x-files
    process: 111108: csh
    NAME    PRIVILEGE    VALUE    FLAG   ACTION            RECIPIENT
    project.max-lwps
            privileged       3       -   deny                      -
            system       2.15G     max   deny                      -

How to Use prctl to Lower a Resource Control Value

  1. Become superuser or assume an equivalent role.

    Roles contain authorizations and privileged commands. For more information about roles, see Using the Solaris Management Tools With RBAC (Task Map) in System Administration Guide: Basic Administration.

  2. Use the prctl command with the -r option to change the lowest value of the process.max-file-descriptor resource control.
    # prctl -n process.max-file-descriptor -r -v 128 $$

How to Use prctl to Display, Replace, and Verify the Value of a Control on a Project

  1. Become superuser or assume an equivalent role.

    Roles contain authorizations and privileged commands. For more information about roles, see Using the Solaris Management Tools With RBAC (Task Map) in System Administration Guide: Basic Administration.

  2. Display the value of project.cpu-shares in the project group.staff.
    # prctl -n project.cpu-shares -i project group.staff
    project: 2: group.staff
    NAME    PRIVILEGE       VALUE    FLAG   ACTION     RECIPIENT
    project.cpu-shares
            privileged          1       -   none               -
            system          65.5K     max   none 
  3. Replace the current project.cpu-shares value 1 with the value 10.
    # prctl -n project.cpu-shares -v 10 -r -i project group.staff
  4. Display the value of project.cpu-shares in the project group.staff.
    # prctl -n project.cpu-shares -i project group.staff
    project: 2: group.staff
    NAME    PRIVILEGE       VALUE    FLAG   ACTION     RECIPIENT
    project.cpu-shares
            privileged         10       -   none               -
            system          65.5K     max   none 
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