Functions to retrieve system information like total physical memory and total number of logical CPUs adhering to limits set by cgroups. More...

#include <cassert>
#include <cstdint>
#include <thread>
#include "my_config.h"
#include "my_system_api/my_system_api.h"
#include "mysql/components/library_mysys/my_system.h"
#include <unistd.h>

Namespaces
namespace	anonymous_namespace{my_system.cc}

Functions
static uint64_t	total_physical_memory () noexcept
	Get the total physical memory accessible to the server. More...

bool	init_my_physical_memory (ulonglong memory)
	Initialize the my_physical_memory function using server_memory option. More...

uint64_t	my_physical_memory () noexcept
	Determine the total physical memory available in bytes. More...

uint32_t	my_num_vcpus () noexcept
	Determine the total number of logical CPUs available. More...

Variables
ulonglong	anonymous_namespace{my_system.cc}::configured_memory {0}

Detailed Description

Functions to retrieve system information like total physical memory and total number of logical CPUs adhering to limits set by cgroups.

Function Documentation

◆ init_my_physical_memory()

bool init_my_physical_memory ( ulonglong memory )

Initialize the my_physical_memory function using server_memory option.

Parameters

[in] memory Value of the server_memory startup option

Note: The input value of 0 indicates no limits, and underlying container/host configuration must be used

Returns: true on success, false if input memory value is invalid

◆ my_num_vcpus()

uint32_t my_num_vcpus ( )

noexcept

Determine the total number of logical CPUs available.

If process is running within a container, the number of logical CPUs is the maximum limit set for the container. If the process is not running in a container then it uses the appropriate system APIs to determine the number of logical CPUs.

If the API is unable to determine the number of logical CPUs, then it returns 0.

Note: : The container set limits are calculated from the CFS quota and period as quota/period and is round down. A limit of 0.5 will return the value 0 and is treated as though no limits are set.

Returns: number of logical CPUs or 0

◆ my_physical_memory()

uint64_t my_physical_memory ( )

noexcept

Determine the total physical memory available in bytes.

If process is running within a container, then memory available is the maximum limit set for the container. If the process is not running in a container then it uses the appropriate system APIs to determine the available memory.

If the API is unable to determine the available memory, then it returns 0.

Returns: physical memory in bytes or 0

◆ total_physical_memory()

static uint64_t total_physical_memory ( )

inlinestaticnoexcept

Get the total physical memory accessible to the server.

Tries to read cgroup limits first. If failed or no limits were found, then tries to read from the system using corresponding system APIs.

Returns: total physical memory available to the server, or 0 on failure

Namespaces