diff options
-rw-r--r-- | Documentation/cpusets.txt | 18 |
1 files changed, 10 insertions, 8 deletions
diff --git a/Documentation/cpusets.txt b/Documentation/cpusets.txt index 1f5a924d1e56..47e568a9370a 100644 --- a/Documentation/cpusets.txt +++ b/Documentation/cpusets.txt | |||
@@ -635,14 +635,16 @@ prior 'mems' setting, will not be moved. | |||
635 | 635 | ||
636 | There is an exception to the above. If hotplug functionality is used | 636 | There is an exception to the above. If hotplug functionality is used |
637 | to remove all the CPUs that are currently assigned to a cpuset, | 637 | to remove all the CPUs that are currently assigned to a cpuset, |
638 | then the kernel will automatically update the cpus_allowed of all | 638 | then all the tasks in that cpuset will be moved to the nearest ancestor |
639 | tasks attached to CPUs in that cpuset to allow all CPUs. When memory | 639 | with non-empty cpus. But the moving of some (or all) tasks might fail if |
640 | hotplug functionality for removing Memory Nodes is available, a | 640 | cpuset is bound with another cgroup subsystem which has some restrictions |
641 | similar exception is expected to apply there as well. In general, | 641 | on task attaching. In this failing case, those tasks will stay |
642 | the kernel prefers to violate cpuset placement, over starving a task | 642 | in the original cpuset, and the kernel will automatically update |
643 | that has had all its allowed CPUs or Memory Nodes taken offline. User | 643 | their cpus_allowed to allow all online CPUs. When memory hotplug |
644 | code should reconfigure cpusets to only refer to online CPUs and Memory | 644 | functionality for removing Memory Nodes is available, a similar exception |
645 | Nodes when using hotplug to add or remove such resources. | 645 | is expected to apply there as well. In general, the kernel prefers to |
646 | violate cpuset placement, over starving a task that has had all | ||
647 | its allowed CPUs or Memory Nodes taken offline. | ||
646 | 648 | ||
647 | There is a second exception to the above. GFP_ATOMIC requests are | 649 | There is a second exception to the above. GFP_ATOMIC requests are |
648 | kernel internal allocations that must be satisfied, immediately. | 650 | kernel internal allocations that must be satisfied, immediately. |