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✏️ Editing: plugin_scheduler.py

# code for cores isolation was inspired by Tuna implementation
# perf code was borrowed from kernel/tools/perf/python/twatch.py
# thanks to Arnaldo Carvalho de Melo <acme@redhat.com>

from . import base
from .decorators import *
import tuned.logs
import re
from subprocess import *
import threading
import perf
import select
import tuned.consts as consts
import procfs
from tuned.utils.commands import commands
import errno
import os
import collections
import math
# Check existence of scheduler API in os module
try:
	os.SCHED_FIFO
except AttributeError:
	import schedutils

log = tuned.logs.get()

class SchedulerParams(object):
	def __init__(self, cmd, cmdline = None, scheduler = None,
			priority = None, affinity = None, cgroup = None):
		self._cmd = cmd
		self.cmdline = cmdline
		self.scheduler = scheduler
		self.priority = priority
		self.affinity = affinity
		self.cgroup = cgroup

@property
	def affinity(self):
		if self._affinity is None:
			return None
		else:
			return self._cmd.bitmask2cpulist(self._affinity)

@affinity.setter
	def affinity(self, value):
		if value is None:
			self._affinity = None
		else:
			self._affinity = self._cmd.cpulist2bitmask(value)

class IRQAffinities(object):
	def __init__(self):
		self.irqs = {}
		self.default = None
		# IRQs that don't support changing CPU affinity:
		self.unchangeable = []

class SchedulerUtils(object):
	"""
	Class encapsulating scheduler implementation in os module
	"""

_dict_schedcfg2schedconst = {
		"f": "SCHED_FIFO",
		"b": "SCHED_BATCH",
		"r": "SCHED_RR",
		"o": "SCHED_OTHER",
		"i": "SCHED_IDLE",
	}

def __init__(self):
		# {"f": os.SCHED_FIFO...}
		self._dict_schedcfg2num = dict((k, getattr(os, name)) for k, name in self._dict_schedcfg2schedconst.items())
		# { os.SCHED_FIFO: "SCHED_FIFO"... }
		self._dict_num2schedconst = dict((getattr(os, name), name) for name in self._dict_schedcfg2schedconst.values())

def sched_cfg_to_num(self, str_scheduler):
		return self._dict_schedcfg2num.get(str_scheduler)

# Reimplementation of schedstr from schedutils for logging purposes
	def sched_num_to_const(self, scheduler):
		return self._dict_num2schedconst.get(scheduler)

def get_scheduler(self, pid):
		return os.sched_getscheduler(pid)

def set_scheduler(self, pid, sched, prio):
		os.sched_setscheduler(pid, sched, os.sched_param(prio))

def get_affinity(self, pid):
		return os.sched_getaffinity(pid)

def set_affinity(self, pid, affinity):
		os.sched_setaffinity(pid, affinity)

def get_priority(self, pid):
		return os.sched_getparam(pid).sched_priority

def get_priority_min(self, sched):
		return os.sched_get_priority_min(sched)

def get_priority_max(self, sched):
		return os.sched_get_priority_max(sched)

class SchedulerUtilsSchedutils(SchedulerUtils):
	"""
	Class encapsulating scheduler implementation in schedutils module
	"""
	def __init__(self):
		# { "f": schedutils.SCHED_FIFO... }
		self._dict_schedcfg2num = dict((k, getattr(schedutils, name)) for k, name in self._dict_schedcfg2schedconst.items())
		# { schedutils.SCHED_FIFO: "SCHED_FIFO"... }
		self._dict_num2schedconst = dict((getattr(schedutils, name), name) for name in self._dict_schedcfg2schedconst.values())

def get_scheduler(self, pid):
		return schedutils.get_scheduler(pid)

def set_scheduler(self, pid, sched, prio):
		schedutils.set_scheduler(pid, sched, prio)

def get_affinity(self, pid):
		return schedutils.get_affinity(pid)

def set_affinity(self, pid, affinity):
		schedutils.set_affinity(pid, affinity)

def get_priority(self, pid):
		return schedutils.get_priority(pid)

def get_priority_min(self, sched):
		return schedutils.get_priority_min(sched)

def get_priority_max(self, sched):
		return schedutils.get_priority_max(sched)

class SchedulerPlugin(base.Plugin):
	r"""
	`scheduler`::
	
	Allows tuning of scheduling priorities, process/thread/IRQ
	affinities, and CPU isolation.
	+
	To prevent processes/threads/IRQs from using certain CPUs, use
	the [option]`isolated_cores` option. It changes process/thread
	affinities, IRQs affinities and it sets `default_smp_affinity`
	for IRQs. The CPU affinity mask is adjusted for all processes and
	threads matching [option]`ps_whitelist` option subject to success
	of the `sched_setaffinity()` system call. The default setting of
	the [option]`ps_whitelist` regular expression is `.*` to match all
	processes and thread names. To exclude certain processes and threads
	use [option]`ps_blacklist` option. The value of this option is also
	interpreted as a regular expression and process/thread names (`ps -eo
	cmd`) are matched against that expression. Profile rollback allows
	all matching processes and threads to run on all CPUs and restores
	the IRQ settings prior to the profile application.
	+
	Multiple regular expressions for [option]`ps_whitelist`
	and [option]`ps_blacklist` options are allowed and separated by
	`;`. Quoted semicolon `\;` is taken literally.
	+
	.Isolate CPUs 2-4
	====
	----
	[scheduler]
	isolated_cores=2-4
	ps_blacklist=.*pmd.*;.*PMD.*;^DPDK;.*qemu-kvm.*
	----
	Isolate CPUs 2-4 while ignoring processes and threads matching
	`ps_blacklist` regular expressions.
	====
	The [option]`irq_process` option controls whether the scheduler plugin
	applies the `isolated_cores` parameter to IRQ affinities. The default
	value is `true`, which means that the scheduler plugin will move all
	possible IRQs away from the isolated cores. When `irq_process` is set
	to `false`, the plugin will not change any IRQ affinities.
	====
	The [option]`default_irq_smp_affinity` option controls the values
	*TuneD* writes to `/proc/irq/default_smp_affinity`. The file specifies
	default affinity mask that applies to all non-active IRQs. Once an
	IRQ is allocated/activated its affinity bitmask will be set to the
	default mask.
	+
	The following values are supported:
	+
	--
	`calc`::
	Content of `/proc/irq/default_smp_affinity` will be calculated
	from the `isolated_cores` parameter. Non-isolated cores
	are calculated as an inversion of the `isolated_cores`. Then
	the intersection of the non-isolated cores and the previous
	content of `/proc/irq/default_smp_affinity` is written to
	`/proc/irq/default_smp_affinity`. If the intersection is
	an empty set, then just the non-isolated cores are written to
	`/proc/irq/default_smp_affinity`. This behavior is the default if
	the parameter `default_irq_smp_affinity` is omitted.
	`ignore`::
	*TuneD* will not touch `/proc/irq/default_smp_affinity`.
	explicit cpulist::
	The cpulist (such as 1,3-4) is unpacked and written directly to
	`/proc/irq/default_smp_affinity`.
	--
	+
	.An explicit CPU list to set the default IRQ smp affinity to CPUs 0 and 2
	====
	----
	[scheduler]
	isolated_cores=1,3
	default_irq_smp_affinity=0,2
	----
	====
	To adjust scheduling policy, priority and affinity for a group of
	processes/threads, use the following syntax.
	+
	[subs="+quotes,+macros"]
	----
	group.__groupname__=__rule_prio__:__sched__:__prio__:__affinity__:__regex__
	----
	+
	where `__rule_prio__` defines internal *TuneD* priority of the
	rule. Rules are sorted based on priority. This is needed for
	inheritence to be able to reorder previously defined rules. Equal
	`__rule_prio__` rules should be processed in the order they were
	defined. However, this is Python interpreter dependant. To disable
	an inherited rule for `__groupname__` use:
	+
	[subs="+quotes,+macros"]
	----
	group.__groupname__=
	----
	+
	`__sched__` must be one of:
	*`f`* for FIFO,
	*`b`* for batch,
	*`r`* for round robin,
	*`o`* for other,
	*`*`* do not change.
	+
	`__affinity__` is CPU affinity in hexadecimal. Use `*` for no change.
	+
	`__prio__` scheduling priority (see `chrt -m`).
	+
	`__regex__` is Python regular expression. It is matched against the output of
	+
	[subs="+quotes,+macros"]
	----
	ps -eo cmd
	----
	+
	Any given process name may match more than one group. In such a case,
	the priority and scheduling policy are taken from the last matching
	`__regex__`.
	+
	.Setting scheduling policy and priorities to kernel threads and watchdog
	====
	----
	[scheduler]
	group.kthreads=0:*:1:*:\[.*\]$
	group.watchdog=0:f:99:*:\[watchdog.*\]
	----
	====
	+
	The scheduler plug-in uses perf event loop to catch newly created
	processes. By default it listens to `perf.RECORD_COMM` and
	`perf.RECORD_EXIT` events. By setting [option]`perf_process_fork`
	option to `true`, `perf.RECORD_FORK` events will be also listened
	to. In other words, child processes created by the `fork()` system
	call will be processed. Since child processes inherit CPU affinity
	from their parents, the scheduler plug-in usually does not need to
	explicitly process these events. As processing perf events can
	pose a significant CPU overhead, the [option]`perf_process_fork`
	option parameter is set to `false` by default. Due to this, child
	processes are not processed by the scheduler plug-in.
	+
	The CPU overhead of the scheduler plugin can be mitigated by using
	the scheduler [option]`runtime` option and setting it to `0`. This
	will completely disable the dynamic scheduler functionality and the
	perf events will not be monitored and acted upon. The disadvantage
	ot this approach is the procees/thread tuning will be done only at
	profile application.
	+
	.Disabling the scheduler dynamic functionality
	====
	----
	[scheduler]
	runtime=0
	isolated_cores=1,3
	----
	====
	+
	NOTE: For perf events, memory mapped buffer is used. Under heavy load
	the buffer may overflow. In such cases the `scheduler` plug-in
	may start missing events and failing to process some newly created
	processes. Increasing the buffer size may help. The buffer size can
	be set with the [option]`perf_mmap_pages` option. The value of this
	parameter has to expressed in powers of 2. If it is not the power
	of 2, the nearest higher power of 2 value is calculated from it
	and this calculated value used. If the [option]`perf_mmap_pages`
	option is omitted, the default kernel value is used.
	+
	The scheduler plug-in supports process/thread confinement using
	cgroups v1.
	+
	[option]`cgroup_mount_point` option specifies the path to mount the
	cgroup filesystem or where *TuneD* expects it to be mounted. If unset,
	`/sys/fs/cgroup/cpuset` is expected.
	+
	If [option]`cgroup_groups_init` option is set to `1` *TuneD*
	will create (and remove) all cgroups defined with the `cgroup*`
	options. This is the default behavior. If it is set to `0` the
	cgroups need to be preset by other means.
	+
	If [option]`cgroup_mount_point_init` option is set to `1`,
	*TuneD* will create (and remove) the cgroup mountpoint. It implies
	`cgroup_groups_init = 1`. If set to `0` the cgroups mount point
	needs to be preset by other means. This is the default behavior.
	+
	The [option]`cgroup_for_isolated_cores` option is the cgroup
	name used for the [option]`isolated_cores` option functionality. For
	example, if a system has 4 CPUs, `isolated_cores=1` means that all
	processes/threads will be moved to CPUs 0,2-3.
	The scheduler plug-in will isolate the specified core by writing
	the calculated CPU affinity to the `cpuset.cpus` control file of
	the specified cgroup and move all the matching processes/threads to
	this group. If this option is unset, classic cpuset affinity using
	`sched_setaffinity()` will be used.
	+
	[option]`cgroup.__cgroup_name__` option defines affinities for
	arbitrary cgroups. Even hierarchic cgroups can be used, but the
	hieararchy needs to be specified in the correct order. Also *TuneD*
	does not do any sanity checks here, with the exception that it forces
	the cgroup to be under [option]`cgroup_mount_point`.
	+
	The syntax of the scheduler option starting with `group.` has been
	augmented to use `cgroup.__cgroup_name__` instead of the hexadecimal
	`__affinity__`. The matching processes will be moved to the cgroup
	`__cgroup_name__`. It is also possible to use cgroups which have
	not been defined by the [option]`cgroup.` option as described above,
	i.e. cgroups not managed by *TuneD*.
	+
	All cgroup names are sanitized by replacing all all dots (`.`) with
	slashes (`/`). This is to prevent the plug-in from writing outside
	[option]`cgroup_mount_point`.
	+
	.Using cgroups v1 with the scheduler plug-in
	====
	----
	[scheduler]
	cgroup_mount_point=/sys/fs/cgroup/cpuset
	cgroup_mount_point_init=1
	cgroup_groups_init=1
	cgroup_for_isolated_cores=group
	cgroup.group1=2
	cgroup.group2=0,2
	
	group.ksoftirqd=0:f:2:cgroup.group1:ksoftirqd.*
	ps_blacklist=ksoftirqd.*;rcuc.*;rcub.*;ktimersoftd.*
	isolated_cores=1
	----
	Cgroup `group1` has the affinity set to CPU 2 and the cgroup `group2`
	to CPUs 0,2. Given a 4 CPU setup, the [option]`isolated_cores=1`
	option causes all processes/threads to be moved to CPU
	cores 0,2-3. Processes/threads that are blacklisted by the
	[option]`ps_blacklist` regular expression will not be moved.
	
	The scheduler plug-in will isolate the specified core by writing the
	CPU affinity 0,2-3 to the `cpuset.cpus` control file of the `group`
	and move all the matching processes/threads to this cgroup.
	====
	Option [option]`cgroup_ps_blacklist` allows excluding processes
	which belong to the blacklisted cgroups. The regular expression specified
	by this option is matched against cgroup hierarchies from
	`/proc/PID/cgroups`. Cgroups v1 hierarchies from `/proc/PID/cgroups`
	are separated by commas ',' prior to regular expression matching. The
	following is an example of content against which the regular expression
	is matched against: `10:hugetlb:/,9:perf_event:/,8:blkio:/`
	+
	Multiple regular expressions can be separated by semicolon ';'. The
	semicolon represents a logical 'or' operator.
	+
	.Cgroup-based exclusion of processes from the scheduler
	====
	----
	[scheduler]
	isolated_cores=1
	cgroup_ps_blacklist=:/daemons\b
	----
	
	The scheduler plug-in will move all processes away from core 1 except processes which
	belong to cgroup '/daemons'. The '\b' is a regular expression
	metacharacter that matches a word boundary.
	
	----
	[scheduler]
	isolated_cores=1
	cgroup_ps_blacklist=\b8:blkio:
	----
	
	The scheduler plug-in will exclude all processes which belong to a cgroup
	with hierarchy-ID 8 and controller-list blkio.
	====
	Recent kernels moved some `sched_` and `numa_balancing_` kernel run-time
	parameters from `/proc/sys/kernel`, managed by the `sysctl` utility, to
	`debugfs`, typically mounted under `/sys/kernel/debug`.  TuneD provides an
	abstraction mechanism for the following parameters via the scheduler plug-in:
	[option]`sched_min_granularity_ns`, [option]`sched_latency_ns`,
	[option]`sched_wakeup_granularity_ns`, [option]`sched_tunable_scaling`,
	[option]`sched_migration_cost_ns`, [option]`sched_nr_migrate`,
	[option]`numa_balancing_scan_delay_ms`,
	[option]`numa_balancing_scan_period_min_ms`,
	[option]`numa_balancing_scan_period_max_ms` and
	[option]`numa_balancing_scan_size_mb`.
	Based on the kernel used, TuneD will write the specified value to the correct
	location.
	+
	.Set tasks' "cache hot" value for migration decisions.
	====
	----
	[scheduler]
	sched_migration_cost_ns=500000
	----
	On the old kernels, this is equivalent to:
	----
	[sysctl]
	kernel.sched_migration_cost_ns=500000
	----
	that is, value `500000` will be written to `/proc/sys/kernel/sched_migration_cost_ns`.
	However, on more recent kernels, the value `500000` will be written to
	`/sys/kernel/debug/sched/migration_cost_ns`.
	====
	"""

def __init__(self, monitor_repository, storage_factory, hardware_inventory, device_matcher, device_matcher_udev, plugin_instance_factory, global_cfg, variables):
		super(SchedulerPlugin, self).__init__(monitor_repository, storage_factory, hardware_inventory, device_matcher, device_matcher_udev, plugin_instance_factory, global_cfg, variables)
		self._has_dynamic_options = True
		self._daemon = consts.CFG_DEF_DAEMON
		self._sleep_interval = int(consts.CFG_DEF_SLEEP_INTERVAL)
		if global_cfg is not None:
			self._daemon = global_cfg.get_bool(consts.CFG_DAEMON, consts.CFG_DEF_DAEMON)
			self._sleep_interval = int(global_cfg.get(consts.CFG_SLEEP_INTERVAL, consts.CFG_DEF_SLEEP_INTERVAL))
		self._cmd = commands()
		# helper variable utilized for showing hint only once that the error may be caused by Secure Boot
		self._secure_boot_hint = None
		# paths cache for sched_ and numa_ tunings
		self._sched_knob_paths_cache = {}
		# default is to whitelist all and blacklist none
		self._ps_whitelist = ".*"
		self._ps_blacklist = ""
		self._cgroup_ps_blacklist_re = ""
		self._cpus = perf.cpu_map()
		self._scheduler_storage_key = self._storage_key(
				command_name = "scheduler")
		self._irq_process = True
		self._irq_storage_key = self._storage_key(
				command_name = "irq")
		self._evlist = None
		try:
			self._scheduler_utils = SchedulerUtils()
		except AttributeError:
			self._scheduler_utils = SchedulerUtilsSchedutils()

def _calc_mmap_pages(self, mmap_pages):
		if mmap_pages is None:
			return None
		try:
			mp = int(mmap_pages)
		except ValueError:
			return 0
		if mp <= 0:
			return 0
		# round up to the nearest power of two value
		return int(2 ** math.ceil(math.log(mp, 2)))

def _instance_init(self, instance):
		instance._evlist = None
		instance._has_dynamic_tuning = False
		instance._has_static_tuning = True
		# this is hack, runtime_tuning should be covered by dynamic_tuning configuration
		# TODO: add per plugin dynamic tuning configuration and use dynamic_tuning configuration
		# instead of runtime_tuning
		instance._runtime_tuning = True

# FIXME: do we want to do this here?
		# recover original values in case of crash
		self._scheduler_original = self._storage.get(
				self._scheduler_storage_key, {})
		if len(self._scheduler_original) > 0:
			log.info("recovering scheduling settings from previous run")
			self._restore_ps_affinity()
			self._scheduler_original = {}
			self._storage.unset(self._scheduler_storage_key)

self._cgroups_original_affinity = dict()

# calculated by isolated_cores setter
		self._affinity = None

self._cgroup_affinity_initialized = False
		self._cgroup = None
		self._cgroups = collections.OrderedDict([(self._sanitize_cgroup_path(option[7:]), self._variables.expand(affinity))
			for option, affinity in instance.options.items() if option[:7] == "cgroup." and len(option) > 7])

instance._scheduler = instance.options

perf_mmap_pages_raw = self._variables.expand(instance.options["perf_mmap_pages"])
		perf_mmap_pages = self._calc_mmap_pages(perf_mmap_pages_raw)
		if perf_mmap_pages == 0:
			log.error("Invalid 'perf_mmap_pages' value specified: '%s', using default kernel value" % perf_mmap_pages_raw)
			perf_mmap_pages = None
		if perf_mmap_pages is not None and str(perf_mmap_pages) != perf_mmap_pages_raw:
			log.info("'perf_mmap_pages' value has to be power of two, specified: '%s', using: '%d'" %
				(perf_mmap_pages_raw, perf_mmap_pages))
		for k in instance._scheduler:
			instance._scheduler[k] = self._variables.expand(instance._scheduler[k])
		if self._cmd.get_bool(instance._scheduler.get("runtime", 1)) == "0":
			instance._runtime_tuning = False
		instance._terminate = threading.Event()
		if self._daemon and instance._runtime_tuning:
			try:
				instance._threads = perf.thread_map()
				evsel = perf.evsel(type = perf.TYPE_SOFTWARE,
					config = perf.COUNT_SW_DUMMY,
					task = 1, comm = 1, mmap = 0, freq = 0,
					wakeup_events = 1, watermark = 1,
					sample_type = perf.SAMPLE_TID | perf.SAMPLE_CPU)
				evsel.open(cpus = self._cpus, threads = instance._threads)
				instance._evlist = perf.evlist(self._cpus, instance._threads)
				instance._evlist.add(evsel)
				if perf_mmap_pages is None:
					instance._evlist.mmap()
				else:
					instance._evlist.mmap(pages = perf_mmap_pages)
			# no perf
			except:
				instance._runtime_tuning = False

def _instance_cleanup(self, instance):
		if instance._evlist:
			for fd in instance._evlist.get_pollfd():
				os.close(fd.name)

@classmethod
	def _get_config_options(cls):
		return {
			"isolated_cores": None,
			"cgroup_mount_point": consts.DEF_CGROUP_MOUNT_POINT,
			"cgroup_mount_point_init": False,
			"cgroup_groups_init": True,
			"cgroup_for_isolated_cores": None,
			"cgroup_ps_blacklist": None,
			"ps_whitelist": None,
			"ps_blacklist": None,
			"irq_process": True,
			"default_irq_smp_affinity": "calc",
			"perf_mmap_pages": None,
			"perf_process_fork": "false",
			"sched_min_granularity_ns": None,
			"sched_latency_ns": None,
			"sched_wakeup_granularity_ns": None,
			"sched_tunable_scaling": None,
			"sched_migration_cost_ns": None,
			"sched_nr_migrate": None,
			"numa_balancing_scan_delay_ms": None,
			"numa_balancing_scan_period_min_ms": None,
			"numa_balancing_scan_period_max_ms": None,
			"numa_balancing_scan_size_mb": None
		}

def _sanitize_cgroup_path(self, value):
		return str(value).replace(".", "/") if value is not None else None

# Raises OSError, IOError
	def _get_cmdline(self, process):
		if not isinstance(process, procfs.process):
			pid = process
			process = procfs.process(pid)
		cmdline = procfs.process_cmdline(process)
		if self._is_kthread(process):
			cmdline = "[" + cmdline + "]"
		return cmdline

# Raises OSError, IOError
	def get_processes(self):
		ps = procfs.pidstats()
		ps.reload_threads()
		processes = {}
		for proc in ps.values():
			try:
				cmd = self._get_cmdline(proc)
				pid = proc["pid"]
				processes[pid] = cmd
				if "threads" in proc:
					for pid in proc["threads"].keys():
						cmd = self._get_cmdline(proc)
						processes[pid] = cmd
			except (OSError, IOError) as e:
				if e.errno == errno.ENOENT \
						or e.errno == errno.ESRCH:
					continue
				else:
					raise
		return processes

# Raises OSError
	# Raises SystemError with old (pre-0.4) python-schedutils
	# instead of OSError
	# If PID doesn't exist, errno == ESRCH
	def _get_rt(self, pid):
		scheduler = self._scheduler_utils.get_scheduler(pid)
		sched_str = self._scheduler_utils.sched_num_to_const(scheduler)
		priority = self._scheduler_utils.get_priority(pid)
		log.debug("Read scheduler policy '%s' and priority '%d' of PID '%d'"
				% (sched_str, priority, pid))
		return (scheduler, priority)

def _set_rt(self, pid, sched, prio):
		sched_str = self._scheduler_utils.sched_num_to_const(sched)
		log.debug("Setting scheduler policy to '%s' and priority to '%d' of PID '%d'."
				% (sched_str, prio, pid))
		try:
			prio_min = self._scheduler_utils.get_priority_min(sched)
			prio_max = self._scheduler_utils.get_priority_max(sched)
			if prio < prio_min or prio > prio_max:
				log.error("Priority for %s must be in range %d - %d. '%d' was given."
						% (sched_str, prio_min,
						prio_max, prio))
		# Workaround for old (pre-0.4) python-schedutils which raised
		# SystemError instead of OSError
		except (SystemError, OSError) as e:
			log.error("Failed to get allowed priority range: %s"
					% e)
		try:
			self._scheduler_utils.set_scheduler(pid, sched, prio)
		except (SystemError, OSError) as e:
			if hasattr(e, "errno") and e.errno == errno.ESRCH:
				log.debug("Failed to set scheduling parameters of PID %d, the task vanished."
						% pid)
			else:
				log.error("Failed to set scheduling parameters of PID %d: %s"
						% (pid, e))

# process is a procfs.process object
	# Raises OSError, IOError
	def _is_kthread(self, process):
		return process["stat"]["flags"] & procfs.pidstat.PF_KTHREAD != 0

# Return codes:
	# 0 - Affinity is fixed
	# 1 - Affinity is changeable
	# -1 - Task vanished
	# -2 - Error
	def _affinity_changeable(self, pid):
		try:
			process = procfs.process(pid)
			if process["stat"].is_bound_to_cpu():
				if process["stat"]["state"] == "Z":
					log.debug("Affinity of zombie task with PID %d cannot be changed, the task's affinity mask is fixed."
							% pid)
				elif self._is_kthread(process):
					log.debug("Affinity of kernel thread with PID %d cannot be changed, the task's affinity mask is fixed."
							% pid)
				else:
					log.warn("Affinity of task with PID %d cannot be changed, the task's affinity mask is fixed."
							% pid)
				return 0
			else:
				return 1
		except (OSError, IOError) as e:
			if e.errno == errno.ENOENT or e.errno == errno.ESRCH:
				log.debug("Failed to get task info for PID %d, the task vanished."
						% pid)
				return -1
			else:
				log.error("Failed to get task info for PID %d: %s"
						% (pid, e))
				return -2
		except (AttributeError, KeyError) as e:
			log.error("Failed to get task info for PID %d: %s"
					% (pid, e))
			return -2

def _store_orig_process_rt(self, pid, scheduler, priority):
		try:
			params = self._scheduler_original[pid]
		except KeyError:
			params = SchedulerParams(self._cmd)
			self._scheduler_original[pid] = params
		if params.scheduler is None and params.priority is None:
			params.scheduler = scheduler
			params.priority = priority

def _tune_process_rt(self, pid, sched, prio):
		cont = True
		if sched is None and prio is None:
			return cont
		try:
			(prev_sched, prev_prio) = self._get_rt(pid)
			if sched is None:
				sched = prev_sched
			self._set_rt(pid, sched, prio)
			self._store_orig_process_rt(pid, prev_sched, prev_prio)
		except (SystemError, OSError) as e:
			if hasattr(e, "errno") and e.errno == errno.ESRCH:
				log.debug("Failed to read scheduler policy of PID %d, the task vanished."
						% pid)
				if pid in self._scheduler_original:
					del self._scheduler_original[pid]
				cont = False
			else:
				log.error("Refusing to set scheduler and priority of PID %d, reading original scheduling parameters failed: %s"
						% (pid, e))
		return cont

def _is_cgroup_affinity(self, affinity):
		return str(affinity)[:7] == "cgroup."

def _store_orig_process_affinity(self, pid, affinity, is_cgroup = False):
		try:
			params = self._scheduler_original[pid]
		except KeyError:
			params = SchedulerParams(self._cmd)
			self._scheduler_original[pid] = params
		if params.affinity is None and params.cgroup is None:
			if is_cgroup:
				params.cgroup = affinity
			else:
				params.affinity = affinity

def _get_cgroup_affinity(self, pid):
		# we cannot use procfs, because it uses comma ',' delimiter which
		# can be ambiguous
		for l in self._cmd.read_file("%s/%s/%s" % (consts.PROCFS_MOUNT_POINT, str(pid), "cgroup"), no_error = True).split("\n"):
			try:
				cgroup = l.split(":cpuset:")[1][1:]
				return cgroup if cgroup != "" else "/"
			except IndexError:
				pass
		return "/"

# it can be arbitrary cgroup even cgroup we didn't set, but it needs to be
	# under "cgroup_mount_point"
	def _set_cgroup(self, pid, cgroup):
		cgroup = self._sanitize_cgroup_path(cgroup)
		path = self._cgroup_mount_point
		if cgroup != "/":
			path = "%s/%s" % (path, cgroup)
		self._cmd.write_to_file("%s/tasks" % path, str(pid), no_error = True)

def _parse_cgroup_affinity(self, cgroup):
		# "cgroup.CGROUP"
		cgroup = cgroup[7:]
		# this should be faster than string comparison
		is_cgroup = not isinstance(cgroup, list) and len(cgroup) > 0
		return is_cgroup, cgroup

def _tune_process_affinity(self, pid, affinity, intersect = False):
		cont = True
		if affinity is None:
			return cont
		try:
			(is_cgroup, cgroup) = self._parse_cgroup_affinity(affinity)
			if is_cgroup:
				prev_affinity = self._get_cgroup_affinity(pid)
				self._set_cgroup(pid, cgroup)
			else:
				prev_affinity = self._get_affinity(pid)
				if intersect:
					affinity = self._get_intersect_affinity(
							prev_affinity, affinity,
							affinity)
				self._set_affinity(pid, affinity)
			self._store_orig_process_affinity(pid,
					prev_affinity, is_cgroup)
		except (SystemError, OSError) as e:
			if hasattr(e, "errno") and e.errno == errno.ESRCH:
				log.debug("Failed to read affinity of PID %d, the task vanished."
						% pid)
				if pid in self._scheduler_original:
					del self._scheduler_original[pid]
				cont = False
			else:
				log.error("Refusing to set CPU affinity of PID %d, reading original affinity failed: %s"
						% (pid, e))
		return cont

#tune process and store previous values
	def _tune_process(self, pid, cmd, sched, prio, affinity):
		cont = self._tune_process_rt(pid, sched, prio)
		if not cont:
			return
		cont = self._tune_process_affinity(pid, affinity)
		if not cont or pid not in self._scheduler_original:
			return
		self._scheduler_original[pid].cmdline = cmd

def _convert_sched_params(self, str_scheduler, str_priority):
		scheduler = self._scheduler_utils.sched_cfg_to_num(str_scheduler)
		if scheduler is None and str_scheduler != "*":
			log.error("Invalid scheduler: %s. Scheduler and priority will be ignored."
					% str_scheduler)
			return (None, None)
		else:
			try:
				priority = int(str_priority)
			except ValueError:
				log.error("Invalid priority: %s. Scheduler and priority will be ignored."
							% str_priority)
				return (None, None)
		return (scheduler, priority)

def _convert_affinity(self, str_affinity):
		if str_affinity == "*":
			affinity = None
		elif self._is_cgroup_affinity(str_affinity):
			affinity = str_affinity
		else:
			affinity = self._cmd.hex2cpulist(str_affinity)
			if not affinity:
				log.error("Invalid affinity: %s. It will be ignored."
						% str_affinity)
				affinity = None
		return affinity

def _convert_sched_cfg(self, vals):
		(rule_prio, scheduler, priority, affinity, regex) = vals
		(scheduler, priority) = self._convert_sched_params(
				scheduler, priority)
		affinity = self._convert_affinity(affinity)
		return (rule_prio, scheduler, priority, affinity, regex)

def _cgroup_create_group(self, cgroup):
		path = "%s/%s" % (self._cgroup_mount_point, cgroup)
		try:
			os.mkdir(path, consts.DEF_CGROUP_MODE)
		except OSError as e:
			log.error("Unable to create cgroup '%s': %s" % (path, e))
		if (not self._cmd.write_to_file("%s/%s" % (path, "cpuset.mems"),
				self._cmd.read_file("%s/%s" % (self._cgroup_mount_point, "cpuset.mems"), no_error = True),
				no_error = True)):
					log.error("Unable to initialize 'cpuset.mems ' for cgroup '%s'" % path)

def _cgroup_initialize_groups(self):
		if self._cgroup is not None and not self._cgroup in self._cgroups:
			self._cgroup_create_group(self._cgroup)
		for cg in self._cgroups:
			self._cgroup_create_group(cg)

def _cgroup_initialize(self):
		log.debug("Initializing cgroups settings")
		try:
			os.makedirs(self._cgroup_mount_point, consts.DEF_CGROUP_MODE)
		except OSError as e:
			log.error("Unable to create cgroup mount point: %s" % e)
		(ret, out) = self._cmd.execute(["mount", "-t", "cgroup", "-o", "cpuset", "cpuset", self._cgroup_mount_point])
		if ret != 0:
			log.error("Unable to mount '%s'" % self._cgroup_mount_point)

def _remove_dir(self, cgroup):
		try:
			os.rmdir(cgroup)
		except OSError as e:
			log.error("Unable to remove directory '%s': %s" % (cgroup, e))

def _cgroup_finalize_groups(self):
		for cg in reversed(self._cgroups):
			self._remove_dir("%s/%s" % (self._cgroup_mount_point, cg))
		if self._cgroup is not None and not self._cgroup in self._cgroups:
			self._remove_dir("%s/%s" % (self._cgroup_mount_point, self._cgroup))

def _cgroup_finalize(self):
		log.debug("Removing cgroups settings")
		(ret, out) = self._cmd.execute(["umount", self._cgroup_mount_point])
		if ret != 0:
			log.error("Unable to umount '%s'" % self._cgroup_mount_point)
			return False
		self._remove_dir(self._cgroup_mount_point)
		d = os.path.dirname(self._cgroup_mount_point)
		if (d != "/"):
			self._remove_dir(d)

def _cgroup_set_affinity_one(self, cgroup, affinity, backup = False):
		if affinity != "":
			log.debug("Setting cgroup '%s' affinity to '%s'" % (cgroup, affinity))
		else:
			log.debug("Skipping cgroup '%s', empty affinity requested" % cgroup)
			return
		path = "%s/%s/%s" % (self._cgroup_mount_point, cgroup, "cpuset.cpus")
		if backup:
			orig_affinity = self._cmd.read_file(path, err_ret = "ERR", no_error = True).strip()
			if orig_affinity != "ERR":
				self._cgroups_original_affinity[cgroup] = orig_affinity
			else:
				log.error("Refusing to set affinity of cgroup '%s', reading original affinity failed" % cgroup)
				return
		if not self._cmd.write_to_file(path, affinity, no_error = True):
			log.error("Unable to set affinity '%s' for cgroup '%s'" % (affinity, cgroup))

def _cgroup_set_affinity(self):
		if self._cgroup_affinity_initialized:
			return
		log.debug("Setting cgroups affinities")
		if self._affinity is not None and self._cgroup is not None and not self._cgroup in self._cgroups:
			self._cgroup_set_affinity_one(self._cgroup, self._affinity, backup = True)
		for cg in self._cgroups.items():
			self._cgroup_set_affinity_one(cg[0], cg[1], backup = True)
		self._cgroup_affinity_initialized = True

def _cgroup_restore_affinity(self):
		log.debug("Restoring cgroups affinities")
		for cg in self._cgroups_original_affinity.items():
			self._cgroup_set_affinity_one(cg[0], cg[1])

def _instance_apply_static(self, instance):
		# need to get "cgroup_mount_point_init", "cgroup_mount_point", "cgroup_groups_init",
		# "cgroup", and initialize mount point and cgroups before super class implementation call
		self._cgroup_mount_point = self._variables.expand(instance.options["cgroup_mount_point"])
		self._cgroup_mount_point_init = self._cmd.get_bool(self._variables.expand(
			instance.options["cgroup_mount_point_init"])) == "1"
		self._cgroup_groups_init = self._cmd.get_bool(self._variables.expand(
			instance.options["cgroup_groups_init"])) == "1"
		self._cgroup = self._sanitize_cgroup_path(self._variables.expand(
			instance.options["cgroup_for_isolated_cores"]))

if self._cgroup_mount_point_init:
			self._cgroup_initialize()
		if self._cgroup_groups_init or self._cgroup_mount_point_init:
			self._cgroup_initialize_groups()

super(SchedulerPlugin, self)._instance_apply_static(instance)

self._cgroup_set_affinity()
		try:
			ps = self.get_processes()
		except (OSError, IOError) as e:
			log.error("error applying tuning, cannot get information about running processes: %s"
					% e)
			return
		sched_cfg = [(option, str(value).split(":", 4)) for option, value in instance._scheduler.items()]
		buf = [(option, self._convert_sched_cfg(vals))
				for option, vals in sched_cfg
				if re.match(r"group\.", option)
				and len(vals) == 5]
		sched_cfg = sorted(buf, key=lambda option_vals: option_vals[1][0])
		sched_all = dict()
		# for runtime tuning
		instance._sched_lookup = {}
		for option, (rule_prio, scheduler, priority, affinity, regex) \
				in sched_cfg:
			try:
				r = re.compile(regex)
			except re.error as e:
				log.error("error compiling regular expression: '%s'" % str(regex))
				continue
			processes = [(pid, cmd) for pid, cmd in ps.items() if re.search(r, cmd) is not None]
			#cmd - process name, option - group name
			sched = dict([(pid, (cmd, option, scheduler, priority, affinity, regex))
					for pid, cmd in processes])
			sched_all.update(sched)
			# make any contained regexes non-capturing: replace "(" with "(?:",
			# unless the "(" is preceded by "\" or followed by "?"
			regex = re.sub(r"(?<!\\)\((?!\?)", "(?:", str(regex))
			instance._sched_lookup[regex] = [scheduler, priority, affinity]
		for pid, (cmd, option, scheduler, priority, affinity, regex) \
				in sched_all.items():
			self._tune_process(pid, cmd, scheduler,
					priority, affinity)
		self._storage.set(self._scheduler_storage_key,
				self._scheduler_original)
		if self._daemon and instance._runtime_tuning:
			instance._thread = threading.Thread(target = self._thread_code, args = [instance])
			instance._thread.start()

def _restore_ps_affinity(self):
		try:
			ps = self.get_processes()
		except (OSError, IOError) as e:
			log.error("error unapplying tuning, cannot get information about running processes: %s"
					% e)
			return
		for pid, orig_params in self._scheduler_original.items():
			# if command line for the pid didn't change, it's very probably the same process
			if pid not in ps or ps[pid] != orig_params.cmdline:
				continue
			if orig_params.scheduler is not None \
					and orig_params.priority is not None:
				self._set_rt(pid, orig_params.scheduler,
						orig_params.priority)
			if orig_params.cgroup is not None:
				self._set_cgroup(pid, orig_params.cgroup)
			elif orig_params.affinity is not None:
				self._set_affinity(pid, orig_params.affinity)
		self._scheduler_original = {}
		self._storage.unset(self._scheduler_storage_key)

def _cgroup_cleanup_tasks_one(self, cgroup):
		cnt = int(consts.CGROUP_CLEANUP_TASKS_RETRY)
		data = " "
		while data != "" and cnt > 0:
			data = self._cmd.read_file("%s/%s/%s" % (self._cgroup_mount_point, cgroup, "tasks"),
				err_ret = " ", no_error = True)
			if data not in ["", " "]:
				for l in data.split("\n"):
					self._cmd.write_to_file("%s/%s" % (self._cgroup_mount_point, "tasks"), l, no_error = True)
			cnt -= 1
		if cnt == 0:
			log.warn("Unable to cleanup tasks from cgroup '%s'" % cgroup)

def _cgroup_cleanup_tasks(self):
		if self._cgroup is not None and not self._cgroup in self._cgroups:
			self._cgroup_cleanup_tasks_one(self._cgroup)
		for cg in self._cgroups:
			self._cgroup_cleanup_tasks_one(cg)

def _instance_unapply_static(self, instance, rollback = consts.ROLLBACK_SOFT):
		super(SchedulerPlugin, self)._instance_unapply_static(instance, rollback)
		if self._daemon and instance._runtime_tuning:
			instance._terminate.set()
			instance._thread.join()
		self._restore_ps_affinity()
		self._cgroup_restore_affinity()
		self._cgroup_cleanup_tasks()
		if self._cgroup_groups_init or self._cgroup_mount_point_init:
			self._cgroup_finalize_groups()
		if self._cgroup_mount_point_init:
			self._cgroup_finalize()

def _cgroup_verify_affinity_one(self, cgroup, affinity):
		log.debug("Verifying cgroup '%s' affinity" % cgroup)
		path = "%s/%s/%s" % (self._cgroup_mount_point, cgroup, "cpuset.cpus")
		current_affinity = self._cmd.read_file(path, err_ret = "ERR", no_error = True)
		if current_affinity == "ERR":
			return True
		current_affinity = self._cmd.cpulist2string(self._cmd.cpulist_pack(current_affinity))
		affinity = self._cmd.cpulist2string(self._cmd.cpulist_pack(affinity))
		affinity_description = "cgroup '%s' affinity" % cgroup
		if current_affinity == affinity:
			log.info(consts.STR_VERIFY_PROFILE_VALUE_OK
					% (affinity_description, current_affinity))
			return True
		else:
			log.error(consts.STR_VERIFY_PROFILE_VALUE_FAIL
					% (affinity_description, current_affinity,
					affinity))
			return False

def _cgroup_verify_affinity(self):
		log.debug("Veryfying cgroups affinities")
		ret = True
		if self._affinity is not None and self._cgroup is not None and not self._cgroup in self._cgroups:
			ret = ret and self._cgroup_verify_affinity_one(self._cgroup, self._affinity)
		for cg in self._cgroups.items():
			ret = ret and self._cgroup_verify_affinity_one(cg[0], cg[1])
		return ret

def _instance_verify_static(self, instance, ignore_missing, devices):
		ret1 = super(SchedulerPlugin, self)._instance_verify_static(instance, ignore_missing, devices)
		ret2 = self._cgroup_verify_affinity()
		return ret1 and ret2

def _add_pid(self, instance, pid, r):
		try:
			cmd = self._get_cmdline(pid)
		except (OSError, IOError) as e:
			if e.errno == errno.ENOENT \
					or e.errno == errno.ESRCH:
				log.debug("Failed to get cmdline of PID %d, the task vanished."
						% pid)
			else:
				log.error("Failed to get cmdline of PID %d: %s"
						% (pid, e))
			return
		v = self._cmd.re_lookup(instance._sched_lookup, cmd, r)
		if v is not None and not pid in self._scheduler_original:
			log.debug("tuning new process '%s' with PID '%d' by '%s'" % (cmd, pid, str(v)))
			(sched, prio, affinity) = v
			self._tune_process(pid, cmd, sched, prio,
					affinity)
			self._storage.set(self._scheduler_storage_key,
					self._scheduler_original)

def _remove_pid(self, instance, pid):
		if pid in self._scheduler_original:
			del self._scheduler_original[pid]
			log.debug("removed PID %d from the rollback database" % pid)
			self._storage.set(self._scheduler_storage_key,
					self._scheduler_original)

def _thread_code(self, instance):
		r = self._cmd.re_lookup_compile(instance._sched_lookup)
		poll = select.poll()
		# Store the file objects in a local variable so that they don't
		# go out of scope too soon. This is a workaround for
		# python3-perf bug rhbz#1659445.
		fds = instance._evlist.get_pollfd()
		for fd in fds:
			poll.register(fd)
		while not instance._terminate.is_set():
			# timeout to poll in milliseconds
			if len(poll.poll(self._sleep_interval * 1000)) > 0 and not instance._terminate.is_set():
				read_events = True
				while read_events:
					read_events = False
					for cpu in self._cpus:
						event = instance._evlist.read_on_cpu(cpu)
						if event:
							read_events = True
							if event.type == perf.RECORD_COMM or \
								(self._perf_process_fork_value and event.type == perf.RECORD_FORK):
								self._add_pid(instance, int(event.tid), r)
							elif event.type == perf.RECORD_EXIT:
								self._remove_pid(instance, int(event.tid))

@command_custom("cgroup_ps_blacklist", per_device = False)
	def _cgroup_ps_blacklist(self, enabling, value, verify, ignore_missing):
		# currently unsupported
		if verify:
			return None
		if enabling and value is not None:
			self._cgroup_ps_blacklist_re = "|".join(["(%s)" % v for v in re.split(r"(?<!\\);", str(value))])

@command_custom("ps_whitelist", per_device = False)
	def _ps_whitelist(self, enabling, value, verify, ignore_missing):
		# currently unsupported
		if verify:
			return None
		if enabling and value is not None:
			self._ps_whitelist = "|".join(["(%s)" % v for v in re.split(r"(?<!\\);", str(value))])

@command_custom("ps_blacklist", per_device = False)
	def _ps_blacklist(self, enabling, value, verify, ignore_missing):
		# currently unsupported
		if verify:
			return None
		if enabling and value is not None:
			self._ps_blacklist = "|".join(["(%s)" % v for v in re.split(r"(?<!\\);", str(value))])

@command_custom("irq_process", per_device = False)
	def _irq_process(self, enabling, value, verify, ignore_missing):
		# currently unsupported
		if verify:
			return None
		if enabling and value is not None:
			self._irq_process = self._cmd.get_bool(value) == "1"

@command_custom("default_irq_smp_affinity", per_device = False)
	def _default_irq_smp_affinity(self, enabling, value, verify, ignore_missing):
		# currently unsupported
		if verify:
			return None
		if enabling and value is not None:
			if value in ["calc", "ignore"]:
				self._default_irq_smp_affinity_value = value
			else:
				self._default_irq_smp_affinity_value = self._cmd.cpulist_unpack(value)

@command_custom("perf_process_fork", per_device = False)
	def _perf_process_fork(self, enabling, value, verify, ignore_missing):
		# currently unsupported
		if verify:
			return None
		if enabling and value is not None:
			self._perf_process_fork_value = self._cmd.get_bool(value) == "1"

# Raises OSError
	# Raises SystemError with old (pre-0.4) python-schedutils
	# instead of OSError
	# If PID doesn't exist, errno == ESRCH
	def _get_affinity(self, pid):
		res = self._scheduler_utils.get_affinity(pid)
		log.debug("Read affinity '%s' of PID %d" % (res, pid))
		return res

def _set_affinity(self, pid, affinity):
		log.debug("Setting CPU affinity of PID %d to '%s'." % (pid, affinity))
		try:
			self._scheduler_utils.set_affinity(pid, affinity)
			return True
		# Workaround for old python-schedutils (pre-0.4) which
		# incorrectly raised SystemError instead of OSError
		except (SystemError, OSError) as e:
			if hasattr(e, "errno") and e.errno == errno.ESRCH:
				log.debug("Failed to set affinity of PID %d, the task vanished."
						% pid)
			else:
				res = self._affinity_changeable(pid)
				if res == 1 or res == -2:
					log.error("Failed to set affinity of PID %d to '%s': %s"
							% (pid, affinity, e))
			return False

# returns intersection of affinity1 with affinity2, if intersection is empty it returns affinity3
	def _get_intersect_affinity(self, affinity1, affinity2, affinity3):
		aff = set(affinity1).intersection(set(affinity2))
		if aff:
			return list(aff)
		return affinity3

def _set_all_obj_affinity(self, objs, affinity, threads = False):
		psl = [v for v in objs if re.search(self._ps_whitelist,
				self._get_stat_comm(v)) is not None]
		if self._ps_blacklist != "":
			psl = [v for v in psl if re.search(self._ps_blacklist,
					self._get_stat_comm(v)) is None]
		if self._cgroup_ps_blacklist_re != "":
			psl = [v for v in psl if re.search(self._cgroup_ps_blacklist_re,
					self._get_stat_cgroup(v)) is None]
		psd = dict([(v.pid, v) for v in psl])
		for pid in psd:
			try:
				cmd = self._get_cmdline(psd[pid])
			except (OSError, IOError) as e:
				if e.errno == errno.ENOENT \
						or e.errno == errno.ESRCH:
					log.debug("Failed to get cmdline of PID %d, the task vanished."
							% pid)
				else:
					log.error("Refusing to set affinity of PID %d, failed to get its cmdline: %s"
							% (pid, e))
				continue
			cont = self._tune_process_affinity(pid, affinity,
					intersect = True)
			if not cont:
				continue
			if pid in self._scheduler_original:
				self._scheduler_original[pid].cmdline = cmd
			# process threads
			if not threads and "threads" in psd[pid]:
				self._set_all_obj_affinity(
						psd[pid]["threads"].values(),
						affinity, True)

def _get_stat_cgroup(self, o):
		try:
			return o["cgroups"]
		except (OSError, IOError, KeyError):
			return ""

def _get_stat_comm(self, o):
		try:
			return o["stat"]["comm"]
		except (OSError, IOError, KeyError):
			return ""

def _set_ps_affinity(self, affinity):
		try:
			ps = procfs.pidstats()
			ps.reload_threads()
			self._set_all_obj_affinity(ps.values(), affinity, False)
		except (OSError, IOError) as e:
			log.error("error applying tuning, cannot get information about running processes: %s"
					% e)

# Returns 0 on success, -2 if changing the affinity is not
	# supported, -1 if some other error occurs.
	def _set_irq_affinity(self, irq, affinity, restoring):
		try:
			affinity_hex = self._cmd.cpulist2hex(affinity)
			log.debug("Setting SMP affinity of IRQ %s to '%s'"
					% (irq, affinity_hex))
			filename = "/proc/irq/%s/smp_affinity" % irq
			with open(filename, "w") as f:
				f.write(affinity_hex)
			return 0
		except (OSError, IOError) as e:
			# EIO is returned by
			# kernel/irq/proc.c:write_irq_affinity() if changing
			# the affinity is not supported
			# (at least on kernels 3.10 and 4.18)
			if hasattr(e, "errno") and e.errno == errno.EIO \
					and not restoring:
				log.debug("Setting SMP affinity of IRQ %s is not supported"
						% irq)
				return -2
			else:
				log.error("Failed to set SMP affinity of IRQ %s to '%s': %s"
						% (irq, affinity_hex, e))
				return -1

def _set_default_irq_affinity(self, affinity):
		try:
			affinity_hex = self._cmd.cpulist2hex(affinity)
			log.debug("Setting default SMP IRQ affinity to '%s'"
					% affinity_hex)
			with open("/proc/irq/default_smp_affinity", "w") as f:
				f.write(affinity_hex)
		except (OSError, IOError) as e:
			log.error("Failed to set default SMP IRQ affinity to '%s': %s"
					% (affinity_hex, e))

def _set_all_irq_affinity(self, affinity):
		irq_original = IRQAffinities()
		irqs = procfs.interrupts()
		for irq in irqs.keys():
			try:
				prev_affinity = irqs[irq]["affinity"]
				log.debug("Read affinity of IRQ '%s': '%s'"
						% (irq, prev_affinity))
			except KeyError:
				continue
			_affinity = self._get_intersect_affinity(prev_affinity, affinity, affinity)
			if set(_affinity) == set(prev_affinity):
				continue
			res = self._set_irq_affinity(irq, _affinity, False)
			if res == 0:
				irq_original.irqs[irq] = prev_affinity
			elif res == -2:
				irq_original.unchangeable.append(irq)

# default affinity
		prev_affinity_hex = self._cmd.read_file("/proc/irq/default_smp_affinity")
		prev_affinity = self._cmd.hex2cpulist(prev_affinity_hex)
		if self._default_irq_smp_affinity_value == "calc":
			_affinity = self._get_intersect_affinity(prev_affinity, affinity, affinity)
		elif self._default_irq_smp_affinity_value != "ignore":
			_affinity = self._default_irq_smp_affinity_value
		if self._default_irq_smp_affinity_value != "ignore":
			self._set_default_irq_affinity(_affinity)
			irq_original.default = prev_affinity
		self._storage.set(self._irq_storage_key, irq_original)

def _restore_all_irq_affinity(self):
		irq_original = self._storage.get(self._irq_storage_key, None)
		if irq_original is None:
			return
		for irq, affinity in irq_original.irqs.items():
			self._set_irq_affinity(irq, affinity, True)
		if self._default_irq_smp_affinity_value != "ignore":
			affinity = irq_original.default
			self._set_default_irq_affinity(affinity)
		self._storage.unset(self._irq_storage_key)

def _verify_irq_affinity(self, irq_description, correct_affinity,
			current_affinity):
		res = set(current_affinity).issubset(set(correct_affinity))
		if res:
			log.info(consts.STR_VERIFY_PROFILE_VALUE_OK
					% (irq_description, current_affinity))
		else:
			log.error(consts.STR_VERIFY_PROFILE_VALUE_FAIL
					% (irq_description, current_affinity,
					correct_affinity))
		return res

def _verify_all_irq_affinity(self, correct_affinity, ignore_missing):
		irq_original = self._storage.get(self._irq_storage_key, None)
		irqs = procfs.interrupts()
		res = True
		for irq in irqs.keys():
			if irq in irq_original.unchangeable and ignore_missing:
				description = "IRQ %s does not support changing SMP affinity" % irq
				log.info(consts.STR_VERIFY_PROFILE_VALUE_MISSING % description)
				continue
			try:
				current_affinity = irqs[irq]["affinity"]
				log.debug("Read SMP affinity of IRQ '%s': '%s'"
						% (irq, current_affinity))
				irq_description = "SMP affinity of IRQ %s" % irq
				if not self._verify_irq_affinity(
						irq_description,
						correct_affinity,
						current_affinity):
					res = False
			except KeyError:
				continue

current_affinity_hex = self._cmd.read_file(
				"/proc/irq/default_smp_affinity")
		current_affinity = self._cmd.hex2cpulist(current_affinity_hex)
		if self._default_irq_smp_affinity_value != "ignore" and not self._verify_irq_affinity("default IRQ SMP affinity",
				current_affinity, correct_affinity if self._default_irq_smp_affinity_value == "calc" else
				self._default_irq_smp_affinity_value):
			res = False
		return res

@command_custom("isolated_cores", per_device = False, priority = 10)
	def _isolated_cores(self, enabling, value, verify, ignore_missing):
		affinity = None
		self._affinity = None
		if value is not None:
			isolated = set(self._cmd.cpulist_unpack(value))
			present = set(self._cpus)
			if isolated.issubset(present):
				affinity = list(present - isolated)
				self._affinity = self._cmd.cpulist2string(affinity)
			else:
				str_cpus = self._cmd.cpulist2string(self._cpus)
				log.error("Invalid isolated_cores specified, '%s' does not match available cores '%s'"
						% (value, str_cpus))
		if (enabling or verify) and affinity is None:
			return None
		# currently only IRQ affinity verification is supported
		if verify:
			if self._irq_process:
				return self._verify_all_irq_affinity(affinity, ignore_missing)
			return True
		elif enabling:
			if self._cgroup:
				self._cgroup_set_affinity()
				ps_affinity = "cgroup.%s" % self._cgroup
			else:
				ps_affinity = affinity
			self._set_ps_affinity(ps_affinity)
			if self._irq_process:
				self._set_all_irq_affinity(affinity)
		else:
			# Restoring processes' affinity is done in
			# _instance_unapply_static()
			if self._irq_process:
				self._restore_all_irq_affinity()

def _get_sched_knob_path(self, prefix, namespace, knob):
		key = "%s_%s_%s" % (prefix, namespace, knob)
		path = self._sched_knob_paths_cache.get(key)
		if path:
			return path
		path = "/proc/sys/kernel/%s_%s" % (namespace, knob)
		if not os.path.exists(path):
			if prefix == "":
				path = "%s/%s" % (namespace, knob)
			else:
				path = "%s/%s/%s" % (prefix, namespace, knob)
			path = "/sys/kernel/debug/%s" % path
			if self._secure_boot_hint is None:
				self._secure_boot_hint = True
		self._sched_knob_paths_cache[key] = path
		return path

def _get_sched_knob(self, prefix, namespace, knob):
		data = self._cmd.read_file(self._get_sched_knob_path(prefix, namespace, knob), err_ret = None)
		if data is None:
			log.error("Error reading '%s'" % knob)
			if self._secure_boot_hint:
				log.error("This may not work with Secure Boot or kernel_lockdown (this hint is logged only once)")
				self._secure_boot_hint = False
		return data

def _set_sched_knob(self, prefix, namespace, knob, value, sim, remove = False):
		if value is None:
			return None
		if not sim:
			if not self._cmd.write_to_file(self._get_sched_knob_path(prefix, namespace, knob), value, \
				no_error = [errno.ENOENT] if remove else False):
					log.error("Error writing value '%s' to '%s'" % (value, knob))
		return value

@command_get("sched_min_granularity_ns")
	def _get_sched_min_granularity_ns(self):
		return self._get_sched_knob("", "sched", "min_granularity_ns")

@command_set("sched_min_granularity_ns")
	def _set_sched_min_granularity_ns(self, value, sim, remove):
		return self._set_sched_knob("", "sched", "min_granularity_ns", value, sim, remove)

@command_get("sched_latency_ns")
	def _get_sched_latency_ns(self):
		return self._get_sched_knob("", "sched", "latency_ns")

@command_set("sched_latency_ns")
	def _set_sched_latency_ns(self, value, sim, remove):
		return self._set_sched_knob("", "sched", "latency_ns", value, sim, remove)

@command_get("sched_wakeup_granularity_ns")
	def _get_sched_wakeup_granularity_ns(self):
		return self._get_sched_knob("", "sched", "wakeup_granularity_ns")

@command_set("sched_wakeup_granularity_ns")
	def _set_sched_wakeup_granularity_ns(self, value, sim, remove):
		return self._set_sched_knob("", "sched", "wakeup_granularity_ns", value, sim, remove)

@command_get("sched_tunable_scaling")
	def _get_sched_tunable_scaling(self):
		return self._get_sched_knob("", "sched", "tunable_scaling")

@command_set("sched_tunable_scaling")
	def _set_sched_tunable_scaling(self, value, sim, remove):
		return self._set_sched_knob("", "sched", "tunable_scaling", value, sim, remove)

@command_get("sched_migration_cost_ns")
	def _get_sched_migration_cost_ns(self):
		return self._get_sched_knob("", "sched", "migration_cost_ns")

@command_set("sched_migration_cost_ns")
	def _set_sched_migration_cost_ns(self, value, sim, remove):
		return self._set_sched_knob("", "sched", "migration_cost_ns", value, sim, remove)

@command_get("sched_nr_migrate")
	def _get_sched_nr_migrate(self):
		return self._get_sched_knob("", "sched", "nr_migrate")

@command_set("sched_nr_migrate")
	def _set_sched_nr_migrate(self, value, sim, remove):
		return self._set_sched_knob("", "sched", "nr_migrate", value, sim, remove)

@command_get("numa_balancing_scan_delay_ms")
	def _get_numa_balancing_scan_delay_ms(self):
		return self._get_sched_knob("sched", "numa_balancing", "scan_delay_ms")

@command_set("numa_balancing_scan_delay_ms")
	def _set_numa_balancing_scan_delay_ms(self, value, sim, remove):
		return self._set_sched_knob("sched", "numa_balancing", "scan_delay_ms", value, sim, remove)

@command_get("numa_balancing_scan_period_min_ms")
	def _get_numa_balancing_scan_period_min_ms(self):
		return self._get_sched_knob("sched", "numa_balancing", "scan_period_min_ms")

@command_set("numa_balancing_scan_period_min_ms")
	def _set_numa_balancing_scan_period_min_ms(self, value, sim, remove):
		return self._set_sched_knob("sched", "numa_balancing", "scan_period_min_ms", value, sim, remove)

@command_get("numa_balancing_scan_period_max_ms")
	def _get_numa_balancing_scan_period_max_ms(self):
		return self._get_sched_knob("sched", "numa_balancing", "scan_period_max_ms")

@command_set("numa_balancing_scan_period_max_ms")
	def _set_numa_balancing_scan_period_max_ms(self, value, sim, remove):
		return self._set_sched_knob("sched", "numa_balancing", "scan_period_max_ms", value, sim, remove)

@command_get("numa_balancing_scan_size_mb")
	def _get_numa_balancing_scan_size_mb(self):
		return self._get_sched_knob("sched", "numa_balancing", "scan_size_mb")

@command_set("numa_balancing_scan_size_mb")
	def _set_numa_balancing_scan_size_mb(self, value, sim, remove):
		return self._set_sched_knob("sched", "numa_balancing", "scan_size_mb", value, sim, remove)

MR SKB