内存分析功能验证-阿里云帮助中心

本文档指导开发者完成阿里云移动监控iOS SDK的内存分析的功能验证。

1. 大对象

编写测试代码，触发大块内存分配。例如：

Object C

#import <mach/mach.h>

vm_address_t address;
vm_size_t size = (vm_size_t)(10 * 1024 * 1024); // 10MB
kern_return_t ret = vm_allocate((vm_map_t)mach_task_self(), &address, size, VM_FLAGS_ANYWHERE);

Swift

import Darwin

var address: vm_address_t = 0 
let size: vm_size_t = vm_size_t(10 * 1024 * 1024)   // 10 MB
let ret: kern_return_t = vm_allocate(mach_task_self_, &address, size, VM_FLAGS_ANYWHERE)

触发大块内存分配后，大概2分钟后在控制台-内存分析-大对象页面查看
说明
- 大对象数据从采集到上传到控制台显示，存在大约2~3分钟延迟；

2. 内存泄漏

编写测试代码，触发对象之间循环引用。例如：

Object C

@interface CycleTestViewController : UIViewController
@property (nonatomic, strong) CycleTestViewController *nextVC;
@end

@implementation CycleTestViewController
@end

// 创建3个CycleTestViewController对象
CycleTestViewController *vc1 = [[CycleTestViewController alloc] init];
CycleTestViewController *vc2 = [[CycleTestViewController alloc] init];
CycleTestViewController *vc3= [[CycleTestViewController alloc] init];

vc1.nextVC = vc2;
vc2.nextVC = vc3;
vc3.nextVC = vc1;//形成环：vc3 -> vc1

Swift

import UIKit

class CycleTestViewController: UIViewController {
    var nextVC: CycleTestViewController?

    deinit {
        print("\(self) is deallocated")   // 如果发生循环引用，这里永远不会打印
    }
}

do {
    let vc1 = CycleTestViewController()
    let vc2 = CycleTestViewController()
    let vc3 = CycleTestViewController()

    vc1.nextVC = vc2
    vc2.nextVC = vc3
    vc3.nextVC = vc1       // 形成环：vc3 → vc1
}

触发循环引用后，应用切换到手机后台，大概2分钟后在控制台-内存分析-内存泄漏页面查看

3. OOM

编写测试代码，触发应用OOM崩溃。例如：

Object C

#import <Foundation/Foundation.h>

@interface VMAllocator : NSObject
@property (nonatomic, strong) NSMutableArray *vmAddresses;
- (void)allocateMemory;
@end

// VMAllocator.m
#import "VMAllocator.h"
#import <mach/mach.h>

@implementation VMAllocator

- (instancetype)init {
    self = [super init];
    if (self) {_vmAddresses = [[NSMutableArray alloc] init];
    }
    return self;
}

- (void)allocateMemory {
    // 以下会导致应用OOM
    for (NSUInteger i = 0; i < 1000; i++) {
        vm_address_t address;
        vm_size_t size = (vm_size_t)(10 * 1024 * 1024);
        kern_return_t ret = vm_allocate((vm_map_t)mach_task_self(), &address, size, VM_FLAGS_ANYWHERE);
        if (ret != ERR_SUCCESS) {
            NSLog(@"vm_allocate failed");
            return;
        }
        [self.vmAddresses addObject:[NSValue valueWithPointer:(void *)address]];
    }
}

- (void)dealloc {
    for (NSValue *value in self.vmAddresses) {
        vm_address_t address = (vm_address_t)[value pointerValue];
        vm_deallocate((vm_map_t)mach_task_self(), address,10 * 1024 *1024);
    }
}

@end

Swift

import Foundation
import Darwin

class VMAllocator {
    var vmAddresses: [vm_address_t] = []
    
    func allocateMemory() {
        for _ in0..<1000 {
            var address: vm_address_t = 0
            let size: vm_size_t =10 * 1024 * 1024
            let ret = vm_allocate(mach_task_self_, &address, size, VM_FLAGS_ANYWHERE)
            if ret != KERN_SUCCESS {
                print("vm_allocate failed")
                return
            }
            vmAddresses.append(address)
        }
    }
    
    deinit {
        for address in vmAddresses {
            vm_deallocate(mach_task_self_, address, 10 * 1024 * 1024)
        }
    }
}

应用下次启动后，在控制台-内存分析-OOM页面查看。