new system calls are added for cpusets - all support for querying and
modifying cpusets is via this cpuset file system.
-The /proc/<pid>/status file for each task has two added lines,
+The /proc/<pid>/status file for each task has four added lines,
displaying the tasks cpus_allowed (on which CPUs it may be scheduled)
and mems_allowed (on which Memory Nodes it may obtain memory),
-in the format seen in the following example:
+in the two formats seen in the following example:
Cpus_allowed: ffffffff,ffffffff,ffffffff,ffffffff
+ Cpus_allowed_list: 0-127
Mems_allowed: ffffffff,ffffffff
+ Mems_allowed_list: 0-63
Each cpuset is represented by a directory in the cgroup file system
containing (on top of the standard cgroup files) the following
- memory_migrate flag: if set, move pages to cpusets nodes
- cpu_exclusive flag: is cpu placement exclusive?
- mem_exclusive flag: is memory placement exclusive?
+ - mem_hardwall flag: is memory allocation hardwalled
- memory_pressure: measure of how much paging pressure in cpuset
In addition, the root cpuset only has the following file:
The following rules apply to each cpuset:
- Its CPUs and Memory Nodes must be a subset of its parents.
- - It can only be marked exclusive if its parent is.
+ - It can't be marked exclusive unless its parent is.
- If its cpu or memory is exclusive, they may not overlap any sibling.
These rules, and the natural hierarchy of cpusets, enable efficient
a direct ancestor or descendent, may share any of the same CPUs or
Memory Nodes.
-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.
+A cpuset that is mem_exclusive *or* mem_hardwall is "hardwalled",
+i.e. it restricts kernel allocations for page, buffer and other data
+commonly shared by the kernel across multiple users. All cpusets,
+whether hardwalled 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 job's 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.
1.5 What is memory_pressure ?
flag, and if set, a call to a new routine cpuset_mem_spread_node()
returns the node to prefer for the allocation.
-Similarly, setting 'memory_spread_cache' turns on the flag
+Similarly, setting 'memory_spread_slab' turns on the flag
PF_SPREAD_SLAB, and appropriately marked slab caches will allocate
pages from the node returned by cpuset_mem_spread_node().
2 : search cores in a package.
3 : search cpus in a node [= system wide on non-NUMA system]
( 4 : search nodes in a chunk of node [on NUMA system] )
- ( 5~ : search system wide [on NUMA system])
+ ( 5 : search system wide [on NUMA system] )
+
+The system default is architecture dependent. The system default
+can be changed using the relax_domain_level= boot parameter.
This file is per-cpuset and affect the sched domain where the cpuset
belongs to. Therefore if the flag 'sched_load_balance' of a cpuset
In this directory you can find several files:
# ls
-cpus cpu_exclusive mems mem_exclusive tasks
+cpu_exclusive memory_migrate mems tasks
+cpus memory_pressure notify_on_release
+mem_exclusive memory_spread_page sched_load_balance
+mem_hardwall memory_spread_slab sched_relax_domain_level
Reading them will give you information about the state of this cpuset:
the CPUs and Memory Nodes it can use, the processes that are using
git.openpandora.org / pandora-kernel.git / blobdiff