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Diffstat (limited to 'Documentation/vm/numa_memory_policy.txt')
| -rw-r--r-- | Documentation/vm/numa_memory_policy.txt | 14 |
1 files changed, 7 insertions, 7 deletions
diff --git a/Documentation/vm/numa_memory_policy.txt b/Documentation/vm/numa_memory_policy.txt index 6aaaeb38730..badb0507608 100644 --- a/Documentation/vm/numa_memory_policy.txt +++ b/Documentation/vm/numa_memory_policy.txt @@ -8,7 +8,8 @@ The current memory policy support was added to Linux 2.6 around May 2004. This document attempts to describe the concepts and APIs of the 2.6 memory policy support. -Memory policies should not be confused with cpusets (Documentation/cpusets.txt) +Memory policies should not be confused with cpusets +(Documentation/cgroups/cpusets.txt) which is an administrative mechanism for restricting the nodes from which memory may be allocated by a set of processes. Memory policies are a programming interface that a NUMA-aware application can take advantage of. When @@ -44,7 +45,7 @@ most general to most specific: to establish the task policy for a child task exec()'d from an executable image that has no awareness of memory policy. See the MEMORY POLICY APIS section, below, for an overview of the system call - that a task may use to set/change it's task/process policy. + that a task may use to set/change its task/process policy. In a multi-threaded task, task policies apply only to the thread [Linux kernel task] that installs the policy and any threads @@ -173,7 +174,6 @@ Components of Memory Policies allocation fails, the kernel will search other nodes, in order of increasing distance from the preferred node based on information provided by the platform firmware. - containing the cpu where the allocation takes place. Internally, the Preferred policy uses a single node--the preferred_node member of struct mempolicy. When the internal @@ -274,9 +274,9 @@ Components of Memory Policies For example, consider a task that is attached to a cpuset with mems 2-5 that sets an Interleave policy over the same set with MPOL_F_RELATIVE_NODES. If the cpuset's mems change to 3-7, the - interleave now occurs over nodes 3,5-6. If the cpuset's mems + interleave now occurs over nodes 3,5-7. If the cpuset's mems then change to 0,2-3,5, then the interleave occurs over nodes - 0,3,5. + 0,2-3,5. Thanks to the consistent remapping, applications preparing nodemasks to specify memory policies using this flag should @@ -300,7 +300,7 @@ decrement this reference count, respectively. mpol_put() will only free the structure back to the mempolicy kmem cache when the reference count goes to zero. -When a new memory policy is allocated, it's reference count is initialized +When a new memory policy is allocated, its reference count is initialized to '1', representing the reference held by the task that is installing the new policy. When a pointer to a memory policy structure is stored in another structure, another reference is added, as the task's reference will be dropped @@ -423,7 +423,7 @@ a command line tool, numactl(8), exists that allows one to: + set the shared policy for a shared memory segment via mbind(2) -The numactl(8) tool is packages with the run-time version of the library +The numactl(8) tool is packaged with the run-time version of the library containing the memory policy system call wrappers. Some distributions package the headers and compile-time libraries in a separate development package. |