Enable calculation of several kernel parameters

[ThiloSolbrig]

Changes:

• max_size_in_gb_hugepages: When configure_hugepages_by: memory, limit GB of hugepages to a percentage of physical memory to prevent overallocating
• nr_hugepages_percent: Replace fixed hugepage size (2MB) by system's actual hugepage size (just in case it changes) and add two pages per instance, which is empirically better than just two pages overall
• nr_hugepages_memory': Same asnr_hugepages_percent, plus hugepages capmax_size_in_gb_hugepages`

Enhancements:

• Provides a few aggregates man can use to calculate kernel parameters, i.e.
  • oracle_databases_processes_sum: Sum of processes init-Parameter over all databases
  • oracle_databases_processes_max: Largest processes init-Parameter over all databases
  • oracle_databases_sga_sum: Sum of max(sga_target, sga_max_size) init-Parameter over all databases
  • oracle_databases_sga_max: Largest max(sga_target, sga_max_size) init-Parameter over all databases
  • sysctl_kernel_sem: kernel.sem based on processes init-Parameters (increases values only, unless sysctl_kernel_sem_force==true
  • sysctl_kernel_panic: 0 or 1, according to system's kdump state

Note (1): Kernel paramers are no actually set by these changes. Aggregates rather can be used to e.g. configure oracle_sysctl list or size_in_gb_hugepages.

Example:

size_in_gb_hugepages: "{{ oracle_databases_sga_sum | default(0) | int / 1024**3 }}"
oracle_sysctl:
  - name: kernel.panic # sysctl_kernel_panic defined by orahost_meta
    value: "{{ sysctl_kernel_panic }}"
  - name: kernel.sem
    value: "{{ sysctl_kernel_sem }}"
  - name: kernel.shmall # Doc ID 301830.1
    value: "{{ (( oracle_databases_sga_sum | default(0) | int ) / ( page_size_bytes | int )) | int }}"

Note (2): ASM instance should be described if it's forced to use hugepages:

oracle_asm_instance:
  - init_parameters:
      - name: sga_target
        value: 4G
      - name: processes
        value: "{{ (oracle_databases | default([])) | length * 450 + 50 }}"

[Rendanic]

Closes #450