内存泄漏动态检测（valgrind）
初步判断是否有泄漏
Linux 内存性能优化 —— 高内存使用及内存泄漏排查
比如该文的介绍，需要初步了解top free -h等命令；
主要看free
内存泄漏检测方法：
静态我常用的是cppcheck；
动态的 Linux下内存泄漏定位方法
这个文章介绍的就不错
如：valgrind
按照该教程，大概复现了一下：
valgrind
比如下面这段代码；
1.需要添加头文件#include <mcheck.h>
2.怀疑泄漏的地方，两端成对使用
mtrace();
//怀疑出问题的代码
//int * hhh = new int; * hhh =1; --加了一个new，未 delete
//pthread_join(ppid[i], 0); --屏蔽了线程的资源阻塞回收
muntrace();
3.编译；
4.运行
valgrind --log-file='./log1' --leak-check=full --track-fds=yes ./test
前提你的系统支持valgrind，可用
valgrind --version查看是否支持
其中 选项有 输出日志目录；检测选项 ；运行程序等
// filename: test.c
#define _GNU_SOURCE
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <sched.h>
#include <pthread.h>
#include <mcheck.h>
// 用来打印当前的线程信息：调度策略是什么？优先级是多少？
void get_thread_info(const int thread_index)
{int policy;struct sched_param param;printf("\\n====> thread_index = %d \\n", thread_index);pthread_getschedparam(pthread_self(), &policy, ¶m);if (SCHED_OTHER == policy)printf("thread_index %d: SCHED_OTHER \\n", thread_index);else if (SCHED_FIFO == policy)printf("thread_index %d: SCHED_FIFO \\n", thread_index);else if (SCHED_RR == policy)printf("thread_index %d: SCHED_RR \\n", thread_index);printf("thread_index %d: priority = %d \\n", thread_index, param.sched_priority);
}// 线程函数，
void *thread_routine(void *args)
{// 参数是：线程索引号。四个线程，索引号从 1 到 4，打印信息中使用。int thread_index = *(int *)args;// 为了确保所有的线程都创建完毕，让线程睡眠1秒。sleep(1);// 打印一下线程相关信息：调度策略、优先级。get_thread_info(thread_index);long num = 0;for (int i = 0; i < 2; i++){for (int j = 0; j < 5000000; j++){// 没什么意义，纯粹是模拟 CPU 密集计算。float f1 = ((i+1) * 345.45) * 12.3 * 45.6 / 78.9 / ((j+1) * 4567.89);float f2 = (i+1) * 12.3 * 45.6 / 78.9 * (j+1);float f3 = f1 / f2;}usleep(1000);// 打印计数信息，为了能看到某个线程正在执行printf("thread_index %d: num = %ld \\n", thread_index, num++);}// 线程执行结束printf("thread_index %d: exit \\n", thread_index);return 0;
}int main(void)
{mtrace();//int * hhh = new int; * hhh =1;// 一共创建四个线程：0和1-实时线程，2和3-普通线程(非实时)int thread_num = 4;// 分配的线程索引号，会传递给线程参数int index[4] = {1, 2, 3, 4};// 用来保存 4 个线程的 id 号pthread_t ppid[4];// 用来设置 2 个实时线程的属性：调度策略和优先级pthread_attr_t attr[2];struct sched_param param[2];// 实时线程，必须由 root 用户才能创建if (0 != getuid()){printf("Please run as root \\n");//exit(0);}// 创建 4 个线程for (int i = 0; i < thread_num; i++){cpu_set_t mask;int cpus = sysconf(_SC_NPROCESSORS_CONF);CPU_ZERO(&mask);CPU_SET(0, &mask);if (pthread_setaffinity_np(pthread_self(), sizeof(mask), &mask) < 0){printf("set thread affinity failed! \\n");} if (i <= 1) // 前2个创建实时线程{// 初始化线程属性pthread_attr_init(&attr[i]);// 设置调度策略为：SCHED_FIFO SCHED_RRint res = pthread_attr_setschedpolicy(&attr[i], SCHED_FIFO);if(res != 0) printf("i =1 or 2 \\n");// 设置优先级为 51，52。param[i].__sched_priority = 51 + i;res = pthread_attr_setschedparam(&attr[i], ¶m[i]);if(res != 0) printf("i =1 or 2 \\n");// 设置线程属性：不要继承 main 线程的调度策略和优先级。pthread_attr_setinheritsched(&attr[i], PTHREAD_EXPLICIT_SCHED);// 创建线程pthread_create(&ppid[i], &attr[i],thread_routine, (void *)&index[i]);}else // 后两个创建普通线程{pthread_create(&ppid[i], 0, thread_routine, (void *)&index[i]);}}//pthread_join(ppid[0], 0);
//pthread_join(ppid[1], 0);
//pthread_join(ppid[2], 0);
//pthread_join(ppid[3], 0);// 等待 4 个线程执行结束//for (int i = 0; i < 2; i++)//pthread_join(ppid[i], 0);for (int i = 0; i < 2; i++)//pthread_attr_destroy(&attr[i]);muntrace();
}
日志
hann@hann-virtual-machine:~/linux_app/pthread$ cat log1
==8015== Memcheck, a memory error detector
==8015== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==8015== Using Valgrind-3.13.0 and LibVEX; rerun with -h for copyright info
==8015== Command: ./test
==8015== Parent PID: 7229
==8015==
==8015==
==8015== FILE DESCRIPTORS: 4 open at exit.
==8015== Open file descriptor 3: /home/hann/linux_app/pthread/log1
==8015== <inherited from parent>
==8015==
==8015== Open file descriptor 2: /dev/pts/1
==8015== <inherited from parent>
==8015==
==8015== Open file descriptor 1: /dev/pts/1
==8015== <inherited from parent>
==8015==
==8015== Open file descriptor 0: /dev/pts/1
==8015== <inherited from parent>
==8015==
==8015==
==8015== HEAP SUMMARY:
==8015== in use at exit: 1,156 bytes in 5 blocks
==8015== total heap usage: 10 allocs, 5 frees, 205,124 bytes allocated
==8015==
==8015== 4 bytes in 1 blocks are definitely lost in loss record 1 of 3
==8015== at 0x4C3217F: operator new(unsigned long) (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==8015== by 0x108EA3: main (in /home/hann/linux_app/pthread/test)
==8015==
==8015== 576 bytes in 2 blocks are possibly lost in loss record 2 of 3
==8015== at 0x4C33B25: calloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==8015== by 0x4013646: allocate_dtv (dl-tls.c:286)
==8015== by 0x4013646: _dl_allocate_tls (dl-tls.c:530)
==8015== by 0x4E46227: allocate_stack (allocatestack.c:627)
==8015== by 0x4E46227: pthread_create@@GLIBC_2.2.5 (pthread_create.c:644)
==8015== by 0x109168: main (in /home/hann/linux_app/pthread/test)
==8015==
==8015== 576 bytes in 2 blocks are possibly lost in loss record 3 of 3
==8015== at 0x4C33B25: calloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==8015== by 0x4013646: allocate_dtv (dl-tls.c:286)
==8015== by 0x4013646: _dl_allocate_tls (dl-tls.c:530)
==8015== by 0x4E46227: allocate_stack (allocatestack.c:627)
==8015== by 0x4E46227: pthread_create@@GLIBC_2.2.5 (pthread_create.c:644)
==8015== by 0x1091AF: main (in /home/hann/linux_app/pthread/test)
==8015==
==8015== LEAK SUMMARY:
==8015== definitely lost: 4 bytes in 1 blocks
==8015== indirectly lost: 0 bytes in 0 blocks
==8015== possibly lost: 1,152 bytes in 4 blocks
==8015== still reachable: 0 bytes in 0 blocks
==8015== suppressed: 0 bytes in 0 blocks
==8015==
==8015== For counts of detected and suppressed errors, rerun with: -v
==8015== ERROR SUMMARY: 3 errors from 3 contexts (suppressed: 0 from 0)其中有问题的点：
1.8015 4 bytes in 1 blocks are definitely lost in loss record 1 of 3
8015 at 0x4C3217F: operator new(unsigned long) (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
8015 by 0x108EA3: main (in /home/hann/linux_app/pthread/test)
2.8015 by 0x4E46227: allocate_stack (allocatestack.c:627)
8015 by 0x4E46227: pthread_create@@GLIBC_2.2.5