my_system_api_cgroup.cc File Reference

Functions to retrieve total physical memory and total number of logical CPUs available to the server by reading the limits set by cgroups. More...

#include <cassert>
#include <climits>
#include <cstdint>
#include <fstream>
#include <optional>
#include <string_view>
#include "my_config.h"
#include "my_system_api.h"
#include <unistd.h>

Namespaces
namespace	anonymous_namespace{my_system_api_cgroup.cc}

Functions
template<typename... Args>
bool	anonymous_namespace{my_system_api_cgroup.cc}::read_line_from_file (const std::string_view &path, Args &...args)
	Utility: Read the first line from the file specified in path and copy its contents into the arguments passed. More...
std::optional< uint32_t >	anonymous_namespace{my_system_api_cgroup.cc}::cgroup_v1_cpu ()
	Read CPU limits as if it were set by cgroup v1. More...
std::optional< uint64_t >	anonymous_namespace{my_system_api_cgroup.cc}::cgroup_v1_memory ()
	Read memory limits as if it were set by cgroup v1. More...
std::optional< uint32_t >	anonymous_namespace{my_system_api_cgroup.cc}::cgroup_v2_cpu ()
	Read CPU limits as if it were set by cgroup v2. More...
std::optional< uint64_t >	anonymous_namespace{my_system_api_cgroup.cc}::cgroup_v2_memory ()
	Read Memory limits as if it were set by cgroup v2. More...
uint64_t	my_cgroup_mem_limit ()
	Read the memory limit set by the container. More...
uint32_t	my_cgroup_vcpu_limit ()
	Read the CPU limit set by the container. More...

Variables
constexpr std::string_view	anonymous_namespace{my_system_api_cgroup.cc}::quota_path {"/sys/fs/cgroup/cpu/cpu.cfs_quota_us"}
	cgroup v1 path to file containing CPU quota More...
constexpr std::string_view	anonymous_namespace{my_system_api_cgroup.cc}::period_path {"/sys/fs/cgroup/cpu/cpu.cfs_period_us"}
	cgroup v1 path to file containing CPU period More...
constexpr std::string_view	anonymous_namespace{my_system_api_cgroup.cc}::mem_path_v1
	cgroup v1 path to file containing Memory limits More...
constexpr std::string_view	anonymous_namespace{my_system_api_cgroup.cc}::cpu_path_v2 {"/sys/fs/cgroup/cpu.max"}
	cgroup v2 path to file containing CPU limts More...
constexpr std::string_view	anonymous_namespace{my_system_api_cgroup.cc}::mem_path_v2 {"/sys/fs/cgroup/memory.max"}
	cgroup v2 path to file containing Memory limits More...

Detailed Description

Functions to retrieve total physical memory and total number of logical CPUs available to the server by reading the limits set by cgroups.

Function Documentation

my_cgroup_mem_limit()

uint64_t my_cgroup_mem_limit

(

)

Read the memory limit set by the container.

Try cgroup v2, and then cgroup v1

Returns

memory limit set by cgroup v2 or cgroup v1; or 0

Note

Return value of 0 implies either no limits are set or server is not running in a container

my_cgroup_vcpu_limit()

uint32_t my_cgroup_vcpu_limit

(

)

Read the CPU limit set by the container.

Try cgroup v2, and then cgroup v1

Returns

CPU limit set by cgroup v2 or cgroup v1; or 0

Note

Return value of 0 implies either no limits are set or server is not running in a container