Go语言实现基于内存消耗的缓存自动淘汰机制

package main

import (
    "fmt"
    "syscall"
)

// MemStats 结构体用于存储内存统计信息
type MemStats struct {
    Total uint64 // 总物理内存 (字节)
    Free  uint64 // 空闲物理内存 (字节)
    Used  uint64 // 已用物理内存 (字节)
}

// ReadSysMemStats 从Linux系统获取内存统计信息
func ReadSysMemStats(s *MemStats) error {
    if s == nil {
        return fmt.Errorf("MemStats pointer cannot be nil")
    }

    var info syscall.Sysinfo_t
    err := syscall.Sysinfo(&info)
    if err != nil {
        return fmt.Errorf("failed to get sysinfo: %w", err)
    }

    // Sysinfo_t 中的内存单位是字节
    s.Total = info.Totalram
    s.Free = info.Freeram
    s.Used = s.Total - s.Free

    return nil
}

func main() {
    var stats MemStats
    err := ReadSysMemStats(&stats)
    if err != nil {
        fmt.Printf("Error reading memory stats: %v\n", err)
        return
    }
    fmt.Printf("Linux System Memory:\n")
    fmt.Printf("  Total: %d bytes (%.2f GB)\n", stats.Total, float64(stats.Total)/(1<<30))
    fmt.Printf("  Free:  %d bytes (%.2f GB)\n", stats.Free, float64(stats.Free)/(1<<30))
    fmt.Printf("  Used:  %d bytes (%.2f GB)\n", stats.Used, float64(stats.Used)/(1<<30))
}

package main

/*
#include <mach/mach.h>
#include <mach/mach_host.h>
*/
import "C" // 导入C语言代码

import (
    "fmt"
    "unsafe"
)

// MemStats 结构体用于存储内存统计信息
type MemStats struct {
    Total uint64 // 总物理内存 (字节)
    Free  uint64 // 空闲物理内存 (字节)
    Used  uint64 // 已用物理内存 (字节)
}

// ReadSysMemStats 从macOS系统获取内存统计信息
func ReadSysMemStats(s *MemStats) error {
    if s == nil {
        return fmt.Errorf("MemStats pointer cannot be nil")
    }

    var vm_pagesize C.vm_size_t
    var vm_stat C.vm_statistics_data_t
    var count C.mach_msg_type_number_t = C.HOST_VM_INFO_COUNT

    host_port := C.host_t(C.mach_host_self())

    // 获取页大小
    C.host_page_size(host_port, &vm_pagesize)

    // 获取VM统计信息
    status := C.host_statistics(
        host_port,
        C.HOST_VM_INFO,
        C.host_info_t(unsafe.Pointer(&vm_stat)),
        &count)

    if status != C.KERN_SUCCESS {
        return fmt.Errorf("could not get vm statistics: %d", status)
    }

    // 统计信息以页为单位，需要乘以页大小转换为字节
    freePages := uint64(vm_stat.free_count)
    activePages := uint64(vm_stat.active_count)
    inactivePages := uint64(vm_stat.inactive_count)
    wiredPages := uint64(vm_stat.wire_count)
    pagesize := uint64(vm_pagesize)

    // 计算已用和空闲内存
    // 注意：macOS的内存统计可能比Linux更复杂，这里简化为常用页面类型
    s.Used = (activePages + inactivePages + wiredPages) * pagesize
    s.Free = freePages * pagesize
    s.Total = s.Used + s.Free // 总内存是已用加空闲

    return nil
}

func main() {
    var stats MemStats
    err := ReadSysMemStats(&stats)
    if err != nil {
        fmt.Printf("Error reading memory stats: %v\n", err)
        return
    }
    fmt.Printf("macOS System Memory:\n")
    fmt.Printf("  Total: %d bytes (%.2f GB)\n", stats.Total, float64(stats.Total)/(1<<30))
    fmt.Printf("  Free:  %d bytes (%.2f GB)\n", stats.Free, float64(stats.Free)/(1<<30))
    fmt.Printf("  Used:  %d bytes (%.2f GB)\n", stats.Used, float64(stats.Used)/(1<<30))
}