Cpuplugd checks for system polarization before adjusting cpu hotplug
states. Currently, if the sysfs attribute for polarization is not
present cpuplugd does not make any adjustments. Add a new polarization
type PLR_NONE to reflect systems with no polarization state and allow
cpuplugd to adjust cpu hotplugging.
Signed-off-by: Mete Durlu <meted@linux.ibm.com>
Reviewed-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Reviewed-by: Jan Höppner <hoeppner@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
On vertical polarization, kernel can be adjusting CPU capacities
dynamically, and cpuplugd can interfere this with hotplug operations
causing performance degradation. To prevent this, check if system has
switched its polarization state, and act accordingly.
If system is on vertical polarization when daemon starts, no CPU hotplug
action is triggered. If system changes to vertical polarization during
daemon runtime, revert cpuhotplug adjustments and stop further CPU
hotplug actions. If system switches back to horizontal polarization
during runtime of the daemon, start evaluating CPU hotplug rules and
trigger adjustments.
Reviewed-by: Steffen Eiden <seiden@linux.ibm.com>
Reviewed-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Signed-off-by: Mete Durlu <meted@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
Simplify the cpu management parts of cpuplugd code by introducing
functions from libutil and rework some logic to drop some assumptions
about how kernel assigns cpuids.
Right now cpuplugd assumes that the cpuids are always sequential and
there are no gaps in between, however kernel does not guarantee that.
Make cpuplugd compliant by traversing cpu sysfs entries instead.
Reviewed-by: Steffen Eiden <seiden@linux.ibm.com>
Reviewed-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Signed-off-by: Mete Durlu <meted@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
With kernel commit 496bb034f4ff ("s390/smp: disallow CPU hotplug
of CPU 0") it is no longer possible to hotplug CPU 0.
As a side effect, the sysfs handle /sys/devices/system/cpu/cpu0/online
does no longer exist. Since cpuplugd relies on checking all online
handles of all CPUs, this change causes cpuplugd to fail as it
interprets a non existing online file as an indicator that no other CPUs
with higher IDs exist as well. This leads to cpuplugd assuming that
there are no CPUs available.
Instead of checking for the online file, it is preferable to check for
the existence of the parent folder to verify the existence of a CPU.
As a consequence, all other checks for non-existing online files must
now imply that the CPU is online, but not hotpluggable.
Signed-off-by: Tobias Huschle <huschle@linux.ibm.com>
Tested-by: Mete Durlu <meted@linux.ibm.com>
Reviewed-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
The file pointer in the functions is_online() and cpu_is_configured() is
only freed in the good case. Make sure it is always freed.
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
This commit is based on the s390-tools-1.39.0 version.
Changes on top of s390-tools-1.39.0:
- Add MIT license to all source files
- Add LICENSE file
- Transform REAMDE to README.md (markdown)
- Add AUTHORS.md file
- Add CONTRIBUTING.md file
- Move changelog from README to CHANGELOG.md file
Reviewed-by: Stefan Haberland <sth@linux.vnet.ibm.com>
Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
