cpuset: update cpuset->effective_{cpus,mems} at hotplug

Browse source

We're going to have separate user-configured masks and effective ones.

Eventually configured masks can only be changed by writing cpuset.cpus
and cpuset.mems, and they won't be restricted by parent cpuset. While
effective masks reflect cpu/memory hotplug and hierachical restriction,
and these are the real masks that apply to the tasks in the cpuset.

We calculate effective mask this way:
  - top cpuset's effective_mask == online_mask, otherwise
  - cpuset's effective_mask == configured_mask & parent effective_mask,
    if the result is empty, it inherits parent effective mask.

Those behavior changes are for default hierarchy only. For legacy
hierarchy, effective_mask and configured_mask are the same, so we won't
break old interfaces.

To make cs->effective_{cpus,mems} to be effective masks, we need to
  - update the effective masks at hotplug
  - update the effective masks at config change
  - take on ancestor's mask when the effective mask is empty

The first item is done here.

This won't introduce behavior change.

Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

...

This commit is contained in:

Li Zefan 2014-07-09 16:47:16 +08:00 • committed by Tejun Heo

parent e2b9a3d7d8

commit 1344ab9c29

1 changed files with 4 additions and 0 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

4

kernel/cpuset.c

View file