linux /proc/pid/smaps各字段含义

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/proc/$PID/smaps文件提供了进程内存映射区域的详细信息。这些信息包括地址范围、权限、偏移量、设备号、inode及文件名等。通过对这些数据的解读可以了解进程如何使用内存，例如匿名内存、共享内存、私有内存的状态，以及它们是否被修改过等。

/proc/$PID/smaps

这里写图片描述
第一行：
08048000-080bc000 地址空间的开始地址 - 结束地址
r-xp 属性。前三个是rwx（读、写、可执行）,如果不具有则为“-”。最后一个是p/s(私有/共享)
00000000 偏移量。如果这段内存是从文件里映射过来的，则偏移量为这段内容在文件中的偏移量。如果不是从文件里面映射过来的则为0.
03:02 If the region was mapped from a file, this is the major and minor device number (in hex) where the file lives.
13130 If the region was mapped from a file, this is the file number.
/bin/bash If the region was mapped from a file, this is the name of the file. This field is blank for anonymous mapped regions. There are also special regions with names like [heap], [stack], or [vdso]. [vdso] stands for virtual dynamic shared object. It’s used by system calls to switch to kernel mode.

Rss-Resident Set Size 实际使用物理内存（包含共享库占用的内存）
Rss=Shared_Clean+Shared_Dirty+Private_Clean+Private_Dirty
Pss 实际使用的物理内存（按比例包含共享库占用的内存）。比如四个进程共享同一个占内存1000MB的共享库，每个进程算进250MB在Pss。
Shared_Clean 、 Shared_Dirty 、 Private_Clean、 Private_Dirty
（shared/private）共享和私有
一个页的clean字段表示没有更改此页，当发生换页时不用写回。dirty表示更改了此页，当发生换页时要写回磁盘。此处这四个值是遍历页表中各个页后得到的。
“Referenced” indicates the amount of memory currently marked as referenced or accessed. “Anonymous” shows the amount of memory that does not belong to any file. Even a mapping associated with a file may contain anonymous pages: when MAP_PRIVATE and a page is modified, the file page is replaced by a private anonymous copy. “Swap” shows how much would-be-anonymous memory is also used, but out on swap.