什么’人顶“说是：RES =代码数据
- q: RES -- Resident size (kb)
- The non-swapped physical memory a task has used.
- RES = CODE + DATA.
- r: CODE -- Code size (kb)
- The amount of physical memory devoted to executable code,also known as the 'text resident set' size or TRS.
- s: DATA -- Data+Stack size (kb)
- The amount of physical memory devoted to other than executable code,also known as the 'data >resident set' size or DRS.
当我运行’顶部-p 4258′,我得到以下内容：
- PID USER PR NI VIRT RES SHR S %cpu %MEM TIME+ CODE DATA COMMAND
- 258 root 16 0 3160 1796 1328 S 0.0 0.3 0:00.10 476 416 bash
1796！= 476 416
为什么？
PS：
linux发行版：
- linux-iguu:~ # lsb_release -a
- LSB Version: core-2.0-noarch:core-3.0-noarch:core-2.0-ia32:core-3.0-ia32:desktop-3.1-ia32:desktop-3.1-noarch:graphics-2.0-ia32:graphics-2.0-noarch:graphics-3.1-ia32:graphics-3.1-noarch
- Distributor ID: SUSE LINUX
- Description: SUSE Linux Enterprise Server 9 (i586)
- Release: 9
- Codename: n/a
内核版本：
- linux-iguu:~ # uname -a
- Linux linux-iguu 2.6.16.60-0.21-default #1 Tue May 6 12:41:02 UTC 2008 i686 i686 i386 GNU/Linux
解决方法
我将在一个程序分配和使用内存时发生什么的例子来解释这一点.具体来说,这个程序：
- #include <stdio.h>
- #include <stdlib.h>
- #include <errno.h>
- #include <string.h>
- int main(){
- int *data,size,count,i;
- printf( "fyi: your ints are %d bytes large\n",sizeof(int) );
- printf( "Enter number of ints to malloc: " );
- scanf( "%d",&size );
- data = malloc( sizeof(int) * size );
- if( !data ){
- perror( "Failed to malloc" );
- exit( EXIT_FAILURE );
- }
- printf( "Enter number of ints to initialize: " );
- scanf( "%d",&count );
- for( i = 0; i < count; i++ ){
- data[i] = 1337;
- }
- printf( "I'm going to hang out here until you hit <enter>" );
- while( getchar() != '\n' );
- while( getchar() != '\n' );
- exit( EXIT_SUCCESS );
- }
这是一个简单的程序,要求您分配多少个整数,分配它们,询问要初始化多少整数,然后初始化它们.对于我分配1250000个整数并初始化其中的500000个的运行：
- $./a.out
- fyi: your ints are 4 bytes large
- Enter number of ints to malloc: 1250000
- Enter number of ints to initialize: 500000
Top报告以下信息：
- PID USER PR NI VIRT RES SHR S %cpu %MEM TIME+ SWAP CODE DATA COMMAND
- <program start>
- 11129 xxxxxxx 16 0 3628 408 336 S 0 0.0 0:00.00 3220 4 124 a.out
- <allocate 1250000 ints>
- 11129 xxxxxxx 16 0 8512 476 392 S 0 0.0 0:00.00 8036 4 5008 a.out
- <initialize 500000 ints>
- 11129 xxxxxxx 15 0 8512 2432 396 S 0 0.0 0:00.00 6080 4 5008 a.out
相关资料为：
- DATA CODE RES VIRT
- before allocation: 124 4 408 3628
- after 5MB allocation: 5008 4 476 8512
- after 2MB initialization: 5008 4 2432 8512
在我malloc’d 5MB的数据后,VIRT和DATA都增加了约5MB,但RES没有.在我触摸了我分配的整数的2MB后,RES的确增加了,但DATA和VIRT保持不变.
VIRT是进程使用的虚拟内存的总量,包括共享和what is over-committed.DATA是不共享的虚拟内存量,而不是代码文本.即,它是进程的虚拟堆栈和堆. RES不是虚拟的：它是对该进程在该特定时间实际使用多少内存的测量.
所以在你的情况下,大的不等式CODE DATA< RES可能是进程包含的共享库.在我的例子(和你的)中,SHR代码数据更接近于RES. 希望这可以帮助.
与top和ps有很多的挥手和巫术.在线有很多文章(咆哮？),关于这些不符之处.例如this和this.
