When you allocate memory on the heap, the only limit is free RAM (or virtual memory). It makes Gb of memory. So why is stack size so limited (around 1 Mb) ? What technical reason prevents you to create really big objects on the stack ? Update : My intent might not be clear, I do not want to allocate huge objects on the stack and I do not need a bigger stack. This question is just pure curi
当您在堆上分配内存时，唯一的限制是可用RAM（或虚拟内存）。 它使Gb的记忆。 那么为什么堆栈大小如此有限（大约1 Mb）呢？ 什么技术原因阻止你在栈上创建真正的大对象？ 更新 ：我的意图可能不明确，我不想在堆栈上分配巨大的对象，我不需要更大的堆栈。 这个问题只是纯粹的好奇心。 我的直觉是以下。 堆栈不像堆一样容易管理。 堆栈需要存储在连续的存储位置。 这意味着您不能根据需要随机分配堆栈，但您至少需要
What is the relationship between ulimit -s <value > and the stack size (at thread level) in the Linux implementation (or for that matter any OS)? Is <number of threads > * <each thread stack size > must be less than < stack size assigned by ulimit command > valid justification? In the below program - each thread allocates char [PTHREAD_STACK_MIN] and 10 threads are cre
ulimit -s <value >和Linux实现（或任何操作系统）的堆栈大小（线程级别）之间的关系是什么？ 是<number of threads > * <each thread stack size >必须小于< stack size assigned by ulimit command >有效对齐？ 在下面的程序中 - 每个线程分配char [PTHREAD_STACK_MIN]并创建10个线程。 但是当ulimit被设置为10 * PTHREAD_STACK_MIN时，它不会因为中止而导致内核崩溃。 对于stacksize的一些随机
I am a bit confused on how a program looks like in memory , my professors told me that the stack and heap grow towards each other with the stack being at a lower memory address. First thing that bothered me with that image is that if the heap grew from high to low then if I allocated an array on the heap shouldn't a pointer to the second element be smaller in int value than a pointer to the
我对一个程序在内存中的表现有些困惑，我的教授告诉我堆栈和堆栈正朝着彼此成长，而堆栈的内存地址较低。 首先让我困扰的是，如果堆从高到低，那么如果我在堆上分配一个数组，不应该使用指向第二个元素的指针小于指向第一个元素的指针的int值？ 这会令人困惑 我做了一些研究，然后找到了这个数字（注意我的问题主要集中在linux上） 布局http://www.cyberplusindia.com/blog/wp-content/uploads/2008/10/memorysegment.gif
In an object of this example class class example { public: int x; } an object would be allocated 4 bytes of memory. As an int would take 4 bytes. How much memory would be allocated to an object of the following class - class node { public: int data; node *prev, *next; }; The int would take four bytes, but what about the 'next' and 'prev' pointers? What about th
在这个例子类的一个对象 class example { public: int x; } 一个对象将被分配4个字节的内存。 作为一个int将需要4个字节。 多少内存将被分配给以下类的对象 - class node { public: int data; node *prev, *next; }; int会占用四个字节，但'next'和'prev'指针呢？ 这个类的对象的总大小呢？ 对象的总大小是sizeof(int) + 2*sizeof(node*) +编译器可能在成员之间添加的任何填充。 使用si
Is memory allocation a system call? For example, malloc and new. Is the heap shared by different processes and managed by the OS. What about private heap? If memory allocation in the heap is managed by the OS, how expensive is this? I would also like to have some link to places where I can read more about this topic. In general, malloc and new do not perform a system call at each invocati
内存分配是系统调用吗？ 例如，malloc和new。 堆由不同的进程共享并由操作系统管理。 私人堆呢？ 如果堆中的内存分配由操作系统管理，那么这有多昂贵？ 我还想有一些链接到我可以阅读更多关于这个主题的地方。 一般来说， malloc和new在每次调用时都不会执行系统调用。 但是，他们使用较低级别的机制来分配大页面的内存。 在Windows上，下层机制是VirtualAlloc() 。 我相信POSIX系统，这有点等同于mmap() 。 这两者
Having some out-of-memory problems with a 32-bit process in Windows I begun using Performance Monitor to log certain counters for that process. Though it is normal that Virtual Bytes is higher than both Private Bytes and Working Set, I found that in my case there was a substantial difference, Virtual Bytes was much higher than both Private Bytes and Working Set. What specific operations and W
在Windows中使用32位进程时遇到内存不足问题，我开始使用性能监视器为该进程记录某些计数器。 虽然虚拟字节比私人字节和工作集都高是正常的，但我发现在我的情况下存在实质性差异，虚拟字节比私人字节和工作集都高。 什么特定的操作和Win32 / CRT函数（使用C或C ++）会增加虚拟字节，但不会增加专用字节和工作集？ 我想这应该是某种共享资源，如果我了解性能监视器中不同计数器的说明。 由于在Windows的不同版本中以及在
I have a program that needs a lot of memory, and it crashes as soon as the 2GB virtual address space is reached. Sysinternals process explorer displays this as "virtual size" column. How can I determine this "virtual size" with C (or C++) code? Ok, I have to query a performance counter for "Virtual Bytes". Perfmon shows the query string (or how it is called) as,
我有一个需要大量内存的程序，一旦达到2GB的虚拟地址空间就会崩溃。 Sysinternals进程管理器将其显示为“虚拟大小”列。 我怎样才能用C（或C ++）代码来确定这个“虚拟大小”？ 好吧，我必须查询“虚拟字节”的性能计数器。 Perfmon在我的德语Win XP安装中显示查询字符串（或其调用方式），例如' Process（firefox） VirtuelleGröße'。 如何确定“当前进程”的查询字符串，并且是否存在非本地化名称？ 根据MSDN：内存性
I need to get the mem usage VIRT and RES at run time of my program and display them. What i tried so far: getrusage (http://linux.die.net/man/2/getrusage) int who = RUSAGE_SELF; struct rusage usage; int ret; ret=getrusage(who,&usage); cout<<usage.ru_maxrss; but i always get 0. On Linux, I've never found an ioctl() solution. For our applications, we coded a general util
我需要在我的程序运行时获取mem使用VIRT和RES并显示它们。 我到目前为止的尝试： getrusage（http://linux.die.net/man/2/getrusage） int who = RUSAGE_SELF; struct rusage usage; int ret; ret=getrusage(who,&usage); cout<<usage.ru_maxrss; 但我总是得到0。 在Linux上，我从来没有找到ioctl（）解决方案。 对于我们的应用程序，我们根据读取/ proc / pid中的文件编写了一个通用实用程序。 有很多
I tried to write a small application to get familiar with the concept of copy-on-write in user space. I've read through the answer by MSalters and figured that it would only work if I started with a mmap 'ed file to store my data in. As I don't need file based persistency, I tried to do the same thing with shared memory. First I mmap 'ed and initialized a shm fd, then I mapped a
我试图编写一个小型应用程序来熟悉用户空间中写入时复制的概念。 我已经阅读了MSalters的答案，并认为只有在开始使用mmap的ed文件来存储数据时，它才会起作用。因为我不需要基于文件的持久性，所以我尝试使用shared记忆。 首先，我mmap “ED和初始化的SHM FD，然后我用映射的第二个副本MAP_PRIVATE并从中再次读取。 然而，从内核中读取会导致内核复制整个内容，花费相当多的时间并耗尽内存的两倍。 为什么它没有COW？ 下面
Let's consider this example. class StaticlyManagedObject { //some class members.... } class DynamiclyManagedObject { StaticlyManagedObject _staticlyManagedObject; //is this still allocated at the stack? } class Foo { DynamiclyManagedObject * _dynamiclyManagedObject; //will be allocated in the heap. Foo() { _dynamiclyManagedObject = new DynamiclyManagedObject(); } } I h
我们来考虑一下这个例子。 class StaticlyManagedObject { //some class members.... } class DynamiclyManagedObject { StaticlyManagedObject _staticlyManagedObject; //is this still allocated at the stack? } class Foo { DynamiclyManagedObject * _dynamiclyManagedObject; //will be allocated in the heap. Foo() { _dynamiclyManagedObject = new DynamiclyManagedObject(); } } 我被告知，