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Description of problem:

File /usr/lib/udev/rules.d/40-redhat.rules contains the following line:

  SUBSYSTEM=="memory", ACTION=="add", ATTR{state}=="offline", ATTR{state}="online"

This ensures that hotplugged memory gets available to the system.  In order to be able to hotunplug the hotplugged memory later, its state should be set to `online_movable' instead of `online'.  Otherwise the system may allocate kernel pages in the hotplugged memory, preventing its removal.  To avoid this problem the rule should look like

  SUBSYSTEM=="memory", ACTION=="add", ATTR{state}=="offline", ATTR{state}="online_movable"

However, there is a kernel bug that prevents this simple change from working, see https://bugzilla.redhat.com/1314306.  It's not possible to set memory blocks as online_movable in random order (it results in "Permission denied" failures), the state must be changed from the highest numbered plugged memory block to the lowest one.  So either the kernel bug should be fixed before the change, or the udev rules should ensure changing the state of the memory blocks to `online_movable' in the proper order (from the highest to the lowest memory block).

Version-Release number of selected component (if applicable):

219-19.el7_2.4.x86_64

Milan, is "online_moveable" also supported by RHEL-6 kernel?

(In reply to Michal Sekletar from comment #1)
> Milan, is "online_moveable" also supported by RHEL-6 kernel?

I don't know, we in RHEV don't need that feature on RHEL-6.

(BTW, beware it's online_movable, not online_moveable.)

 So either the kernel bug should be
> fixed before the change, or the udev rules should ensure changing the state
> of the memory blocks to `online_movable' in the proper order (from the
> highest to the lowest memory block).

We can't do any ordering of events in udev, so lets wait for the kernel fix.

may I ask to open https://bugzilla.redhat.com/show_bug.cgi?id=1314306 to the public? I can not view it's content.

kind regards

Sven

*** This bug has been marked as a duplicate of bug 1563532 ***

(In reply to Sven Kieske from comment #4)
> may I ask to open https://bugzilla.redhat.com/show_bug.cgi?id=1314306 to the
> public? I can not view it's content.
> 
> kind regards
> 
> Sven

the same applies to:

https://bugzilla.redhat.com/show_bug.cgi?id=1563532

this bug is not accessible to me