Manual merge with Linus

1 files changed, 12 insertions, 0 deletions

diff --git a/Documentation/cpusets.txt b/Documentation/cpusets.txt
index ad944c060312..47f4114fbf54 100644
--- a/Documentation/cpusets.txt
+++ b/Documentation/cpusets.txt
@@ -60,6 +60,18 @@ all of the cpus in the system. This removes any overhead due to
 load balancing code trying to pull tasks outside of the cpu exclusive
 cpuset only to be prevented by the tasks' cpus_allowed mask.
 
+A cpuset that is mem_exclusive restricts kernel allocations for
+page, buffer and other data commonly shared by the kernel across
+multiple users.  All cpusets, whether mem_exclusive or not, restrict
+allocations of memory for user space.  This enables configuring a
+system so that several independent jobs can share common kernel
+data, such as file system pages, while isolating each jobs user
+allocation in its own cpuset.  To do this, construct a large
+mem_exclusive cpuset to hold all the jobs, and construct child,
+non-mem_exclusive cpusets for each individual job.  Only a small
+amount of typical kernel memory, such as requests from interrupt
+handlers, is allowed to be taken outside even a mem_exclusive cpuset.
+
 User level code may create and destroy cpusets by name in the cpuset
 virtual file system, manage the attributes and permissions of these
 cpusets and which CPUs and Memory Nodes are assigned to each cpuset,