如果有一个进程读取一个大文件并将其保存在其内存中（或只是一个 malloced char*），并且该主进程是分叉的，如果子进程仅从该内存（或 char*）中读取，根据写时复制，不复制保存指针的内存，并且父子和子共享相同的内存，直到其中任何一个尝试在该内存上写入，在这种情况下，进程会复制内存并更改那。
所以我的问题是，如果实现了复制写入，有没有办法知道子进程使用的不与主进程共享的内存量？换句话说，如果子进程使用来自某些读取调用的父内存，子进程实际使用了多少内存？
top 或 ps 命令只会给出孩子应该拥有的内存总量。（即假设内存或指针中的数据是由孩子复制的。）
有没有办法获取 CoW 语义实际使用的数据量？
我/proc/[pid]/smaps 按照 aix 和 Mat 的建议进行了检查，但我发现的只是很多空的 smaps 文件。我尝试了这个命令来查找哪些文件中有数据：tail -n 5 */smaps | less
我得到的 o/p 是
==> 1012/smaps <==
==> 1074/smaps <==
==> 10/smaps <==
==> 1148/smaps <==
==> 11862/smaps <==
==> 11/smaps <==
==> 1355/smaps <==
==> 1356/smaps <==
==> 1357/smaps <==
==> 1358/smaps <==
==> 1361/smaps <==
==> 13/smaps <==
==> 14900/smaps <==
==> 14/smaps <==
==> 1501/smaps <==
==> 15/smaps <==
==> 1684/smaps <==
==> 1685/smaps <==
==> 16/smaps <==
==> 17772/smaps <==
==> 17827/smaps <==
==> 17/smaps <==
==> 18490/smaps <==
==> 18/smaps <==
==> 1932/smaps <==
==> 1934/smaps <==
==> 19863/smaps <==
==> 19/smaps <==
==> 1/smaps <==
==> 20125/smaps <==
==> 20126/smaps <==
==> 20127/smaps <==
==> 20128/smaps <==
==> 20129/smaps <==
==> 20134/smaps <==
==> 20135/smaps <==
==> 20811/smaps <==
==> 20868/smaps <==
==> 20/smaps <==
==> 21116/smaps <==
==> 21774/smaps <==
==> 21/smaps <==
==> 22393/smaps <==
==> 22394/smaps <==
==> 22395/smaps <==
==> 22398/smaps <==
==> 22639/smaps <==
==> 22824/smaps <==
==> 22/smaps <==
==> 23009/smaps <==
==> 23058/smaps <==
==> 23059/smaps <==
Private_Dirty: 0 kB
Referenced: 0 kB
Swap: 0 kB
KernelPageSize: 4 kB
MMUPageSize: 4 kB
==> 23835/smaps <==
==> 23961/smaps <==
==> 23962/smaps <==
==> 23963/smaps <==
==> 23964/smaps <==
==> 23/smaps <==
==> 24180/smaps <==
==> 24268/smaps <==
==> 24467/smaps <==
==> 24/smaps <==
==> 252/smaps <==
==> 25352/smaps <==
==> 25435/smaps <==
==> 25/smaps <==
==> 26465/smaps <==
==> 26/smaps <==
==> 27884/smaps <==
==> 27/smaps <==
==> 28/smaps <==
==> 29/smaps <==
==> 2/smaps <==
==> 303/smaps <==
==> 30/smaps <==
==> 316/smaps <==
==> 31/smaps <==
==> 32074/smaps <==
==> 32076/smaps <==
==> 32112/smaps <==
Private_Dirty: 0 kB
Referenced: 0 kB
Swap: 0 kB
KernelPageSize: 4 kB
MMUPageSize: 4 kB
==> 32116/smaps <==
Private_Dirty: 0 kB
Referenced: 0 kB
Swap: 0 kB
KernelPageSize: 4 kB
MMUPageSize: 4 kB
==> 322/smaps <==
==> 32466/smaps <==
==> 32467/smaps <==
==> 32/smaps <==
==> 33/smaps <==
==> 34/smaps <==
==> 37/smaps <==
==> 38/smaps <==
==> 3991/smaps <==
==> 3992/smaps <==
==> 39/smaps <==
==> 3/smaps <==
==> 4005/smaps <==
==> 4006/smaps <==
==> 4007/smaps <==
==> 4008/smaps <==
==> 4009/smaps <==
==> 4010/smaps <==
==> 4018/smaps <==
==> 4029/smaps <==
==> 4038/smaps <==
==> 4044/smaps <==
==> 4045/smaps <==
==> 4046/smaps <==
==> 4053/smaps <==
==> 4054/smaps <==
==> 4055/smaps <==
==> 40/smaps <==
==> 41/smaps <==
==> 42/smaps <==
==> 4339/smaps <==
==> 435/smaps <==
==> 436/smaps <==
==> 43/smaps <==
==> 44/smaps <==
==> 45/smaps <==
==> 46/smaps <==
==> 47/smaps <==
==> 48/smaps <==
==> 49/smaps <==
==> 4/smaps <==
==> 50/smaps <==
==> 51/smaps <==
==> 52/smaps <==
==> 53/smaps <==
==> 54/smaps <==
==> 55/smaps <==
==> 56/smaps <==
==> 57/smaps <==
==> 58/smaps <==
==> 5988/smaps <==
==> 59/smaps <==
==> 5/smaps <==
==> 6058/smaps <==
==> 6059/smaps <==
Private_Dirty: 0 kB
Referenced: 0 kB
Swap: 0 kB
KernelPageSize: 4 kB
MMUPageSize: 4 kB
==> 60/smaps <==
==> 61/smaps <==
==> 62/smaps <==
==> 63/smaps <==
==> 64/smaps <==
==> 65/smaps <==
==> 66/smaps <==
==> 67/smaps <==
==> 68/smaps <==
==> 69/smaps <==
==> 6/smaps <==
==> 70/smaps <==
==> 71/smaps <==
==> 72/smaps <==
==> 73/smaps <==
==> 74/smaps <==
==> 771/smaps <==
==> 77/smaps <==
==> 782/smaps <==
==> 78/smaps <==
==> 79/smaps <==
==> 7/smaps <==
==> 80/smaps <==
==> 814/smaps <==
==> 819/smaps <==
==> 81/smaps <==
==> 82/smaps <==
==> 83/smaps <==
==> 84/smaps <==
==> 8654/smaps <==
==> 8655/smaps <==
==> 8656/smaps <==
==> 892/smaps <==
==> 8/smaps <==
==> 949/smaps <==
==> 950/smaps <==
==> 9/smaps <==
==> self/smaps <==
Private_Dirty: 0 kB
Referenced: 0 kB
Swap: 0 kB
KernelPageSize: 4 kB
MMUPageSize: 4 kB
那我现在该怎么办？我有正在运行的空白 smap 的进程。我如何获得那些 pid 的 smaps？