s390/cpufeature: Convert MACHINE_HAS_TOPOLOGY to cpu_has_topology()

Convert MACHINE_HAS_... to cpu_has_...() which uses test_facility() instead
of testing the machine_flags lowcore member if the fea

s390/cpufeature: Convert MACHINE_HAS_TOPOLOGY to cpu_has_topology()

Convert MACHINE_HAS_... to cpu_has_...() which uses test_facility() instead
of testing the machine_flags lowcore member if the feature is present.

test_facility() generates better code since it results in a static branch
without accessing memory. The branch is patched via alternatives by the
decompressor depending on the availability of the required facility.

Reviewed-by: Vasily Gorbik <[email protected]>
Signed-off-by: Heiko Carstens <[email protected]>
Signed-off-by: Vasily Gorbik <[email protected]>

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treewide: const qualify ctl_tables where applicable

Add the const qualifier to all the ctl_tables in the tree except for
watchdog_hardlockup_sysctl, memory_allocation_profiling_sysctls,
loadpin_sysc

treewide: const qualify ctl_tables where applicable

Add the const qualifier to all the ctl_tables in the tree except for
watchdog_hardlockup_sysctl, memory_allocation_profiling_sysctls,
loadpin_sysctl_table and the ones calling register_net_sysctl (./net,
drivers/inifiniband dirs). These are special cases as they use a
registration function with a non-const qualified ctl_table argument or
modify the arrays before passing them on to the registration function.

Constifying ctl_table structs will prevent the modification of
proc_handler function pointers as the arrays would reside in .rodata.
This is made possible after commit 78eb4ea25cd5 ("sysctl: treewide:
constify the ctl_table argument of proc_handlers") constified all the
proc_handlers.

Created this by running an spatch followed by a sed command:
Spatch:
virtual patch

@
depends on !(file in "net")
disable optional_qualifier
@

identifier table_name != {
watchdog_hardlockup_sysctl,
iwcm_ctl_table,
ucma_ctl_table,
memory_allocation_profiling_sysctls,
loadpin_sysctl_table
};
@@

+ const
struct ctl_table table_name [] = { ... };

sed:
sed --in-place \
-e "s/struct ctl_table .table = &uts_kern/const struct ctl_table *table = \&uts_kern/" \
kernel/utsname_sysctl.c

Reviewed-by: Song Liu <[email protected]>
Acked-by: Steven Rostedt (Google) <[email protected]> # for kernel/trace/
Reviewed-by: Martin K. Petersen <[email protected]> # SCSI
Reviewed-by: Darrick J. Wong <[email protected]> # xfs
Acked-by: Jani Nikula <[email protected]>
Acked-by: Corey Minyard <[email protected]>
Acked-by: Wei Liu <[email protected]>
Acked-by: Thomas Gleixner <[email protected]>
Reviewed-by: Bill O'Donnell <[email protected]>
Acked-by: Baoquan He <[email protected]>
Acked-by: Ashutosh Dixit <[email protected]>
Acked-by: Anna Schumaker <[email protected]>
Signed-off-by: Joel Granados <[email protected]>

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s390/hiperdispatch: Add hiperdispatch debug counters

Add three counters to follow and understand hiperdispatch behavior;
* adjustment_count (amount of capacity adjustments triggered)
* greedy_time_m

s390/hiperdispatch: Add hiperdispatch debug counters

Add three counters to follow and understand hiperdispatch behavior;
* adjustment_count (amount of capacity adjustments triggered)
* greedy_time_ms (time spent while all cpus are on high capacity)
* conservative_time_ms (time spent while only entitled cpus are on high
capacity)

These counters can be found under /sys/kernel/debug/s390/hiperdispatch/
Time counters are in <msec> format and only cover the time spent
when hiperdispatch is active.

Acked-by: Vasily Gorbik <[email protected]>
Signed-off-by: Mete Durlu <[email protected]>
Signed-off-by: Vasily Gorbik <[email protected]>

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s390/hiperdispatch: Add hiperdispatch debug attributes

Add two attributes for debug purposes. They can be found under;
/sys/devices/system/cpu/hiperdispatch/
* hd_stime_threshold : allows user to ad

s390/hiperdispatch: Add hiperdispatch debug attributes

Add two attributes for debug purposes. They can be found under;
/sys/devices/system/cpu/hiperdispatch/
* hd_stime_threshold : allows user to adjust steal time threshold
* hd_delay_factor : allows user to adjust delay factor of hiperdispatch
work (after topology updates, delayed work is
always delayed extra by this factor)

hd_stime_threshold can have values between 0-100 as it represents a
percentage value.
hd_delay_factor can have values greater than 1. It is multiplied with
the default delay to achieve a longer interval, pushing back the next
hiperdispatch adjustment after a topology update.

Ex:
if delay interval is 250ms and the delay factor is 4;
delayed interval is now 1000ms(1sec). After each capacity adjustment
or topology change, work has a delayed interval of 1 sec for one
interval.

Acked-by: Vasily Gorbik <[email protected]>
Signed-off-by: Mete Durlu <[email protected]>
Signed-off-by: Vasily Gorbik <[email protected]>

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s390/hiperdispatch: Add hiperdispatch sysctl interface

Expose hiperdispatch controls via sysctl. The user can now toggle
hiperdispatch via assigning 0 or 1 to s390.hiperdispatch attribute.
When hipe

s390/hiperdispatch: Add hiperdispatch sysctl interface

Expose hiperdispatch controls via sysctl. The user can now toggle
hiperdispatch via assigning 0 or 1 to s390.hiperdispatch attribute.
When hiperdipatch is toggled on, it tries to adjust CPU capacities,
while system is in vertical polarization to gain performance benefits
from different CPU polarizations. Disabling hiperdispatch reverts the
CPU capacities to their default (HIGH_CAPACITY) and stops the dynamic
adjustments.

Introduce a kconfig option HIPERDISPATCH_ON which allows users to
use hiperdispatch by default on vertical polarization. Using the
sysctl attribute s390.hiperdispatch would overwrite this behavior.

Acked-by: Vasily Gorbik <[email protected]>
Signed-off-by: Mete Durlu <[email protected]>
Signed-off-by: Vasily Gorbik <[email protected]>

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s390/hiperdispatch: Add trace events

Add trace events to debug hiperdispatch behavior and track domain
rebuilding. Two events provide information about the decision making of
hiperdispatch and the a

s390/hiperdispatch: Add trace events

Add trace events to debug hiperdispatch behavior and track domain
rebuilding. Two events provide information about the decision making of
hiperdispatch and the adjustments made.

Acked-by: Vasily Gorbik <[email protected]>
Co-developed-by: Tobias Huschle <[email protected]>
Signed-off-by: Tobias Huschle <[email protected]>
Signed-off-by: Mete Durlu <[email protected]>
Signed-off-by: Vasily Gorbik <[email protected]>

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s390/hiperdispatch: Add steal time averaging

The measurements done by hiperdispatch can have sudden spikes and dips
during run time. To prevent these outliers effecting the decision making
process a

s390/hiperdispatch: Add steal time averaging

The measurements done by hiperdispatch can have sudden spikes and dips
during run time. To prevent these outliers effecting the decision making
process and causing adjustment overhead, use weighted average of the
steal time.

Acked-by: Vasily Gorbik <[email protected]>
Co-developed-by: Tobias Huschle <[email protected]>
Signed-off-by: Tobias Huschle <[email protected]>
Signed-off-by: Mete Durlu <[email protected]>
Signed-off-by: Vasily Gorbik <[email protected]>

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s390/hiperdispatch: Introduce hiperdispatch

When LPAR is in vertical polarization, CPUs get different polarization
values, namely vertical high, vertical medium and vertical low. These
values repres

s390/hiperdispatch: Introduce hiperdispatch

When LPAR is in vertical polarization, CPUs get different polarization
values, namely vertical high, vertical medium and vertical low. These
values represent the likelyhood of the CPU getting physical runtime.
Vertical high CPUs will always get runtime and others get varying
runtime depending on the load the CEC is under.

Vertical high and vertical medium CPUs are considered the CPUs which the
current LPAR has the entitlement to run on. The vertical lows are on the
other hand are borrowed CPUs which would only be given to the LPAR by
hipervisor when the other LPARs are not utilizing them.

Using the CPU capacities, hint linux scheduler when it should prioritise
vertical high and vertical medium CPUs over vertical low CPUs.
By tracking various system statistics hiperdispatch determines when to
adjust cpu capacities.
After each adjustment, rebuilding of scheduler domains is necessary to
notify the scheduler about capacity changes but since this operation is
costly it should be done as sparsely as possible.

Acked-by: Vasily Gorbik <[email protected]>
Co-developed-by: Tobias Huschle <[email protected]>
Signed-off-by: Tobias Huschle <[email protected]>
Signed-off-by: Mete Durlu <[email protected]>
Signed-off-by: Vasily Gorbik <[email protected]>

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