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modules/sched: Fix sched domain flags parsing

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Recent kernels can have a space-separated list of textual flags rather
than a bitfield packed in an int.
This commit is contained in:
douglas-raillard-arm 2021-02-11 17:43:42 +00:00 committed by Marc Bonnici
parent 552040f390
commit d2b80ccaf9
1 changed files with 129 additions and 42 deletions
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171
devlib/module/sched.py
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@ -15,7 +15,6 @@
import logging
import re
from enum import Enum
from past.builtins import basestring
@ -147,43 +146,44 @@ class SchedProcFSNode(object):
self._dyn_attrs[key] = self._build_node(key, nodes[key])
class DocInt(int):
# See https://stackoverflow.com/a/50473952/5096023
def __new__(cls, value, doc):
new = super(DocInt, cls).__new__(cls, value)
new.__doc__ = doc
return new
class SchedDomainFlag(DocInt, Enum):
class _SchedDomainFlag:
"""
Represents a sched domain flag
Backward-compatible emulation of the former :class:`enum.Enum` that will
work on recent kernels with dynamic sched domain flags name and no value
exposed.
"""
# pylint: disable=bad-whitespace
# Domain flags obtained from include/linux/sched/topology.h on v4.17
# https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux/+/v4.17/include/linux/sched/topology.h#20
SD_LOAD_BALANCE = 0x0001, "Do load balancing on this domain"
SD_BALANCE_NEWIDLE = 0x0002, "Balance when about to become idle"
SD_BALANCE_EXEC = 0x0004, "Balance on exec"
SD_BALANCE_FORK = 0x0008, "Balance on fork, clone"
SD_BALANCE_WAKE = 0x0010, "Balance on wakeup"
SD_WAKE_AFFINE = 0x0020, "Wake task to waking CPU"
SD_ASYM_CPUCAPACITY = 0x0040, "Groups have different max cpu capacities"
SD_SHARE_CPUCAPACITY = 0x0080, "Domain members share cpu capacity"
SD_SHARE_POWERDOMAIN = 0x0100, "Domain members share power domain"
SD_SHARE_PKG_RESOURCES = 0x0200, "Domain members share cpu pkg resources"
SD_SERIALIZE = 0x0400, "Only a single load balancing instance"
SD_ASYM_PACKING = 0x0800, "Place busy groups earlier in the domain"
SD_PREFER_SIBLING = 0x1000, "Prefer to place tasks in a sibling domain"
SD_OVERLAP = 0x2000, "Sched_domains of this level overlap"
SD_NUMA = 0x4000, "Cross-node balancing"
# Only defined in Android
# https://android.googlesource.com/kernel/common/+/android-4.14/include/linux/sched/topology.h#29
SD_SHARE_CAP_STATES = 0x8000, "(Android only) Domain members share capacity state"
@classmethod
def check_version(cls, target, logger):
_INSTANCES = {}
"""
Dictionary storing the instances so that they can be compared with ``is``
operator.
"""
def __new__(cls, name, value, doc=None):
self = super().__new__(cls)
self.name = name
self._value = value
self.__doc__ = doc
return cls._INSTANCES.setdefault(self, self)
def __eq__(self, other):
# We *have to* check for "value" as well, otherwise it will be
# impossible to keep in the same set 2 instances with differing values.
return self.name == other.name and self._value == other._value
def __hash__(self):
return hash((self.name, self._value))
@property
def value(self):
value = self._value
if value is None:
raise AttributeError('The kernel does not expose the sched domain flag values')
else:
return value
@staticmethod
def check_version(target, logger):
"""
Check the target and see if its kernel version matches our view of the world
"""
@ -197,24 +197,111 @@ class SchedDomainFlag(DocInt, Enum):
"but target is running v{}".format(ref_parts, parts)
)
def __str__(self):
return self.name
def __repr__(self):
return '<SchedDomainFlag: {}>'.format(self.name)
class _SchedDomainFlagMeta(type):
"""
Metaclass of :class:`SchedDomainFlag`.
Provides some level of emulation of :class:`enum.Enum` behavior for
backward compatibility.
"""
@property
def _flags(self):
return [
attr
for name, attr in self.__dict__.items()
if name.startswith('SD_')
]
def __getitem__(self, i):
return self._flags[i]
def __len__(self):
return len(self._flags)
# These would be provided by collections.abc.Sequence, but using it on a
# metaclass seems to have issues around __init_subclass__
def __iter__(self):
return iter(self._flags)
def __reversed__(self):
return reversed(self._flags)
def __contains__(self, x):
return x in self._flags
@property
def __members__(self):
return {flag.name: flag for flag in self._flags}
class SchedDomainFlag(_SchedDomainFlag, metaclass=_SchedDomainFlagMeta):
"""
Represents a sched domain flag.
.. note:: ``SD_*`` class attributes are deprecated, new code should never
test a given flag against one of these attributes with ``is`` (.e.g ``x
is SchedDomainFlag.SD_LOAD_BALANCE``. This is because the
``SD_LOAD_BALANCE`` flag exists in two flavors that are not equal: one
with a value (the class attribute) and one without (dynamically created
when parsing flags for new kernels). Old code ran on old kernels should
work fine though.
"""
# pylint: disable=bad-whitespace
# Domain flags obtained from include/linux/sched/topology.h on v4.17
# https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux/+/v4.17/include/linux/sched/topology.h#20
SD_LOAD_BALANCE = _SchedDomainFlag("SD_LOAD_BALANCE", 0x0001, "Do load balancing on this domain")
SD_BALANCE_NEWIDLE = _SchedDomainFlag("SD_BALANCE_NEWIDLE", 0x0002, "Balance when about to become idle")
SD_BALANCE_EXEC = _SchedDomainFlag("SD_BALANCE_EXEC", 0x0004, "Balance on exec")
SD_BALANCE_FORK = _SchedDomainFlag("SD_BALANCE_FORK", 0x0008, "Balance on fork, clone")
SD_BALANCE_WAKE = _SchedDomainFlag("SD_BALANCE_WAKE", 0x0010, "Balance on wakeup")
SD_WAKE_AFFINE = _SchedDomainFlag("SD_WAKE_AFFINE", 0x0020, "Wake task to waking CPU")
SD_ASYM_CPUCAPACITY = _SchedDomainFlag("SD_ASYM_CPUCAPACITY", 0x0040, "Groups have different max cpu capacities")
SD_SHARE_CPUCAPACITY = _SchedDomainFlag("SD_SHARE_CPUCAPACITY", 0x0080, "Domain members share cpu capacity")
SD_SHARE_POWERDOMAIN = _SchedDomainFlag("SD_SHARE_POWERDOMAIN", 0x0100, "Domain members share power domain")
SD_SHARE_PKG_RESOURCES = _SchedDomainFlag("SD_SHARE_PKG_RESOURCES", 0x0200, "Domain members share cpu pkg resources")
SD_SERIALIZE = _SchedDomainFlag("SD_SERIALIZE", 0x0400, "Only a single load balancing instance")
SD_ASYM_PACKING = _SchedDomainFlag("SD_ASYM_PACKING", 0x0800, "Place busy groups earlier in the domain")
SD_PREFER_SIBLING = _SchedDomainFlag("SD_PREFER_SIBLING", 0x1000, "Prefer to place tasks in a sibling domain")
SD_OVERLAP = _SchedDomainFlag("SD_OVERLAP", 0x2000, "Sched_domains of this level overlap")
SD_NUMA = _SchedDomainFlag("SD_NUMA", 0x4000, "Cross-node balancing")
# Only defined in Android
# https://android.googlesource.com/kernel/common/+/android-4.14/include/linux/sched/topology.h#29
SD_SHARE_CAP_STATES = _SchedDomainFlag("SD_SHARE_CAP_STATES", 0x8000, "(Android only) Domain members share capacity state")
class SchedDomain(SchedProcFSNode):
"""
Represents a sched domain as seen through procfs
"""
def __init__(self, nodes):
super(SchedDomain, self).__init__(nodes)
super().__init__(nodes)
obj_flags = set()
for flag in list(SchedDomainFlag):
if self.flags & flag.value == flag.value:
obj_flags.add(flag)
flags = self.flags
# Recent kernels now have a space-separated list of flags instead of a
# packed bitfield
if isinstance(flags, str):
flags = {
_SchedDomainFlag(name=name, value=None)
for name in flags.split()
}
else:
def has_flag(flags, flag):
return flags & flag.value == flag.value
self.flags = obj_flags
flags = {
flag
for flag in SchedDomainFlag
if has_flag(flags, flag)
}
self.flags = flags
class SchedProcFSData(SchedProcFSNode):