numa_setaffinity (2)
Leading comments
Copyright (c) 2008 Christian Brueffer Copyright (c) 2008 Jeffrey Roberson Copyright (c) 2015 Adrian Chadd All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of co...
NAME
numa_getaffinity numa_setaffinity - manage NUMA affinityLIBRARY
Lb libcSYNOPSIS
In sys/param.h In sys/numa.h Ft int Fn numa_getaffinity cpuwhich_t which id_t id struct vm_domain_policy_entry *policy Ft int Fn numa_setaffinity cpuwhich_t which id_t id const struct vm_domain_policy_entry *policyDESCRIPTION
Fn numa_getaffinity and Fn numa_setaffinity allow the manipulation of NUMA policies available to processes and threads. These functions may manipulate NUMA policies that contain many processes or affect only a single object.Valid values for the Fa which argument are documented in cpuset(2). These arguments specify which object set are used. Only CPU_WHICH_TID and CPU_WHICH_PID can be manipulated.
The Fa policy entry contains a vm_domain_policy_entry with the following fields:
struct vm_domain_policy_entry {
vm_domain_policy_type_t policy; /* VM policy */
int domain; /* VM domain, if applicable */
}
Fa vm_domain_policy_type_t policy
is one these:
- VM_POLICY_NONE
- Reset the domain back to none. Any parent object NUMA domain policy will apply. The only valid value for domain is -1.
- VM_POLICY_ROUND_ROBIN
- Select round-robin policy. Pages will be allocated round-robin from each VM domain in order. The only valid value for domain is -1.
- VM_POLICY_FIXED_DOMAIN
- Select fixed-domain only policy. Pages will be allocated from the given domain which must be set to a valid VM domain. Pages will not be allocated from another domain if domain is out of free pages.
- VM_POLICY_FIXED_DOMAIN_ROUND_ROBIN
- Select fixed-domain only policy. Pages will be allocated from domain which must be set to a valid VM domain. If page allocation fails, pages will be round-robin allocated from another domain if domain is out of free pages.
- VM_POLICY_FIRST_TOUCH
- Select first-touch policy. Pages will be allocated from the NUMA domain which the thread is currently scheduled upon. Pages will not be allocated from another domain if the current domain is out of free pages. The only valid value for domain is -1.
- VM_POLICY_FIRST_TOUCH_ROUND_ROBIN
- Select first-touch policy. Pages will be allocated from the NUMA domain which the thread is currently scheduled upon. Pages will be allocated round-robin from another domain if the current domain is out of free pages. The only valid value for domain is -1.
Note that the VM might assign some pages from other domains. For example, if an existing page allocation is covered by a superpage allocation.
Fn numa_getaffinity retrieves the NUMA policy from the object specified by Fa which and Fa id and stores it in the space provided by Fa policy .
Fn numa_setaffinity attempts to set the NUMA policy for the object specified by Fa which and Fa id to the policy in Fa policy .
RETURN VALUES
Rv -stdERRORS
errno can contain these error codes:- Bq Er EINVAL
- The Fa level or Fa which argument was not a valid value.
- Bq Er EINVAL
- The Fa policy argument specified when calling Fn numa_setaffinity did not contain a valid policy.
- Bq Er EFAULT
- The policy pointer passed was invalid.
- Bq Er ESRCH
- The object specified by the Fa id and Fa which arguments could not be found.
- Bq Er ERANGE
- The Fa domain in the given policy was out of the range of possible VM domains available.
- Bq Er EPERM
- The calling process did not have the credentials required to complete the operation.