cpuset: Fix documentation punctuation
Fix cpusets.txt documentation punctuation. Signed-off-by: Greg Thelen <gthelen@google.com> Acked-by: Randy Dunlap <rdunlap@xenotime.net> Acked-by: Paul Menage <menage@google.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
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@ -42,7 +42,7 @@ Nodes to a set of tasks. In this document "Memory Node" refers to
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an on-line node that contains memory.
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Cpusets constrain the CPU and Memory placement of tasks to only
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the resources within a tasks current cpuset. They form a nested
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the resources within a task's current cpuset. They form a nested
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hierarchy visible in a virtual file system. These are the essential
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hooks, beyond what is already present, required to manage dynamic
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job placement on large systems.
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@ -53,11 +53,11 @@ Documentation/cgroups/cgroups.txt.
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Requests by a task, using the sched_setaffinity(2) system call to
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include CPUs in its CPU affinity mask, and using the mbind(2) and
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set_mempolicy(2) system calls to include Memory Nodes in its memory
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policy, are both filtered through that tasks cpuset, filtering out any
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policy, are both filtered through that task's cpuset, filtering out any
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CPUs or Memory Nodes not in that cpuset. The scheduler will not
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schedule a task on a CPU that is not allowed in its cpus_allowed
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vector, and the kernel page allocator will not allocate a page on a
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node that is not allowed in the requesting tasks mems_allowed vector.
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node that is not allowed in the requesting task's mems_allowed vector.
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User level code may create and destroy cpusets by name in the cgroup
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virtual file system, manage the attributes and permissions of these
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@ -121,9 +121,9 @@ Cpusets extends these two mechanisms as follows:
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- Each task in the system is attached to a cpuset, via a pointer
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in the task structure to a reference counted cgroup structure.
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- Calls to sched_setaffinity are filtered to just those CPUs
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allowed in that tasks cpuset.
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allowed in that task's cpuset.
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- Calls to mbind and set_mempolicy are filtered to just
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those Memory Nodes allowed in that tasks cpuset.
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those Memory Nodes allowed in that task's cpuset.
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- The root cpuset contains all the systems CPUs and Memory
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Nodes.
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- For any cpuset, one can define child cpusets containing a subset
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@ -141,11 +141,11 @@ into the rest of the kernel, none in performance critical paths:
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- in init/main.c, to initialize the root cpuset at system boot.
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- in fork and exit, to attach and detach a task from its cpuset.
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- in sched_setaffinity, to mask the requested CPUs by what's
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allowed in that tasks cpuset.
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allowed in that task's cpuset.
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- in sched.c migrate_live_tasks(), to keep migrating tasks within
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the CPUs allowed by their cpuset, if possible.
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- in the mbind and set_mempolicy system calls, to mask the requested
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Memory Nodes by what's allowed in that tasks cpuset.
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Memory Nodes by what's allowed in that task's cpuset.
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- in page_alloc.c, to restrict memory to allowed nodes.
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- in vmscan.c, to restrict page recovery to the current cpuset.
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@ -155,7 +155,7 @@ new system calls are added for cpusets - all support for querying and
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modifying cpusets is via this cpuset file system.
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The /proc/<pid>/status file for each task has four added lines,
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displaying the tasks cpus_allowed (on which CPUs it may be scheduled)
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displaying the task's cpus_allowed (on which CPUs it may be scheduled)
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and mems_allowed (on which Memory Nodes it may obtain memory),
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in the two formats seen in the following example:
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@ -323,17 +323,17 @@ stack segment pages of a task.
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By default, both kinds of memory spreading are off, and memory
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pages are allocated on the node local to where the task is running,
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except perhaps as modified by the tasks NUMA mempolicy or cpuset
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except perhaps as modified by the task's NUMA mempolicy or cpuset
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configuration, so long as sufficient free memory pages are available.
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When new cpusets are created, they inherit the memory spread settings
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of their parent.
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Setting memory spreading causes allocations for the affected page
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or slab caches to ignore the tasks NUMA mempolicy and be spread
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or slab caches to ignore the task's NUMA mempolicy and be spread
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instead. Tasks using mbind() or set_mempolicy() calls to set NUMA
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mempolicies will not notice any change in these calls as a result of
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their containing tasks memory spread settings. If memory spreading
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their containing task's memory spread settings. If memory spreading
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is turned off, then the currently specified NUMA mempolicy once again
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applies to memory page allocations.
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@ -357,7 +357,7 @@ pages from the node returned by cpuset_mem_spread_node().
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The cpuset_mem_spread_node() routine is also simple. It uses the
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value of a per-task rotor cpuset_mem_spread_rotor to select the next
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node in the current tasks mems_allowed to prefer for the allocation.
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node in the current task's mems_allowed to prefer for the allocation.
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This memory placement policy is also known (in other contexts) as
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round-robin or interleave.
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@ -594,7 +594,7 @@ is attached, is subtle.
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If a cpuset has its Memory Nodes modified, then for each task attached
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to that cpuset, the next time that the kernel attempts to allocate
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a page of memory for that task, the kernel will notice the change
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in the tasks cpuset, and update its per-task memory placement to
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in the task's cpuset, and update its per-task memory placement to
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remain within the new cpusets memory placement. If the task was using
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mempolicy MPOL_BIND, and the nodes to which it was bound overlap with
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its new cpuset, then the task will continue to use whatever subset
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@ -603,13 +603,13 @@ was using MPOL_BIND and now none of its MPOL_BIND nodes are allowed
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in the new cpuset, then the task will be essentially treated as if it
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was MPOL_BIND bound to the new cpuset (even though its NUMA placement,
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as queried by get_mempolicy(), doesn't change). If a task is moved
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from one cpuset to another, then the kernel will adjust the tasks
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from one cpuset to another, then the kernel will adjust the task's
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memory placement, as above, the next time that the kernel attempts
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to allocate a page of memory for that task.
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If a cpuset has its 'cpuset.cpus' modified, then each task in that cpuset
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will have its allowed CPU placement changed immediately. Similarly,
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if a tasks pid is written to another cpusets 'cpuset.tasks' file, then its
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if a task's pid is written to another cpusets 'cpuset.tasks' file, then its
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allowed CPU placement is changed immediately. If such a task had been
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bound to some subset of its cpuset using the sched_setaffinity() call,
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the task will be allowed to run on any CPU allowed in its new cpuset,
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@ -626,16 +626,16 @@ cpusets memory placement policy 'cpuset.mems' subsequently changes.
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If the cpuset flag file 'cpuset.memory_migrate' is set true, then when
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tasks are attached to that cpuset, any pages that task had
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allocated to it on nodes in its previous cpuset are migrated
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to the tasks new cpuset. The relative placement of the page within
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to the task's new cpuset. The relative placement of the page within
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the cpuset is preserved during these migration operations if possible.
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For example if the page was on the second valid node of the prior cpuset
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then the page will be placed on the second valid node of the new cpuset.
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Also if 'cpuset.memory_migrate' is set true, then if that cpusets
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Also if 'cpuset.memory_migrate' is set true, then if that cpuset's
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'cpuset.mems' file is modified, pages allocated to tasks in that
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cpuset, that were on nodes in the previous setting of 'cpuset.mems',
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will be moved to nodes in the new setting of 'mems.'
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Pages that were not in the tasks prior cpuset, or in the cpusets
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Pages that were not in the task's prior cpuset, or in the cpuset's
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prior 'cpuset.mems' setting, will not be moved.
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There is an exception to the above. If hotplug functionality is used
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@ -655,7 +655,7 @@ There is a second exception to the above. GFP_ATOMIC requests are
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kernel internal allocations that must be satisfied, immediately.
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The kernel may drop some request, in rare cases even panic, if a
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GFP_ATOMIC alloc fails. If the request cannot be satisfied within
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the current tasks cpuset, then we relax the cpuset, and look for
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the current task's cpuset, then we relax the cpuset, and look for
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memory anywhere we can find it. It's better to violate the cpuset
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than stress the kernel.
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