Commit 0aa7d130 authored by Ondřej Lysoněk's avatar Ondřej Lysoněk

scheduler: Improve logging when setting IRQ affinity

The EIO errno is returned by kernel/irq/proc.c:write_irq_affinity()
if and only if changing SMP affinity of a particular IRQ is not
supported (at least on Linux 3.10 and 4.18). So let's log a failure
to change the affinity only as DEBUG if we get EIO and we are not in
the process of restoring the affinity, because the failure is expected
and there's nothing we can do about it. If we're restoring, use ERROR
log level, so that the user is informed that we failed to restore
the affinity to its original state (this should not happen though).

Other errnos can be significant, so always log them as ERROR.

Resolves: rhbz#1590937
Signed-off-by: default avatarOndřej Lysoněk <>
parent 3534d7da
......@@ -561,13 +561,39 @@ class SchedulerPlugin(base.Plugin):
log.error("error applying tuning, cannot get information about running processes: %s"
% e)
def _set_irq_affinity(self, irq, affinity_hex):
self._cmd.write_to_file("/proc/irq/%s/smp_affinity" % irq,
affinity_hex, no_error = True)
def _set_irq_affinity(self, irq, affinity, restoring):
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:
return True
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)
log.error("Failed to set SMP affinity of IRQ %s to '%s': %s"
% (irq, affinity_hex, e))
return False
def _set_default_irq_affinity(self, affinity_hex):
def _set_default_irq_affinity(self, affinity):
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:
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()
......@@ -582,16 +608,14 @@ class SchedulerPlugin(base.Plugin):
_affinity = self._get_intersect_affinity(prev_affinity, affinity, affinity)
if set(_affinity) == set(prev_affinity):
affinity_hex = self._cmd.cpulist2hex(_affinity)
if self._set_irq_affinity(irq, affinity_hex):
if self._set_irq_affinity(irq, _affinity, False):
irq_original.irqs[irq] = prev_affinity
# default affinity
prev_affinity_hex = self._cmd.read_file("/proc/irq/default_smp_affinity")
prev_affinity = self._cmd.hex2cpulist(prev_affinity_hex)
_affinity = self._get_intersect_affinity(prev_affinity, affinity, affinity)
affinity_hex = self._cmd.cpulist2hex(_affinity)
irq_original.default = prev_affinity
self._storage.set(self._irq_storage_key, irq_original)
......@@ -600,11 +624,9 @@ class SchedulerPlugin(base.Plugin):
if irq_original is None:
for irq, affinity in irq_original.irqs.items():
affinity_hex = self._cmd.cpulist2hex(affinity)
self._set_irq_affinity(irq, affinity_hex)
self._set_irq_affinity(irq, affinity, True)
affinity = irq_original.default
affinity_hex = self._cmd.cpulist2hex(affinity)
@command_custom("isolated_cores", per_device = False, priority = 10)
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