[adm-showard@cmhlcarchapp01 ~]$ cat mem.c #include#include #include int main() { struct rusage r_usage; void *m = malloc(4194304000L); memset(m,0,4194304000L); sleep (60); } [adm-showard@cmhlcarchapp01 ~]$ gcc -o mem mem.c [adm-showard@cmhlcarchapp01 ~]$ ./mem & [1] 25748 [adm-showard@cmhlcarchapp01 ~]$ pmap -d 25748 25748: ./mem Address Kbytes Mode Offset Device Mapping 0000000000400000 4 r-x-- 0000000000000000 000:00018 mem 0000000000600000 4 rw--- 0000000000000000 000:00018 mem 0000003934000000 128 r-x-- 0000000000000000 0fd:00000 ld-2.12.so 0000003934220000 4 r---- 0000000000020000 0fd:00000 ld-2.12.so 0000003934221000 4 rw--- 0000000000021000 0fd:00000 ld-2.12.so 0000003934222000 4 rw--- 0000000000000000 000:00000 [ anon ] 0000003934400000 1576 r-x-- 0000000000000000 0fd:00000 libc-2.12.so 000000393458a000 2048 ----- 000000000018a000 0fd:00000 libc-2.12.so 000000393478a000 16 r---- 000000000018a000 0fd:00000 libc-2.12.so 000000393478e000 8 rw--- 000000000018e000 0fd:00000 libc-2.12.so 0000003934790000 16 rw--- 0000000000000000 000:00000 [ anon ] 00007f2298f8b000 4096016 rw--- 0000000000000000 000:00000 [ anon ] 00007f2392f9c000 4 rw--- 0000000000000000 000:00000 [ anon ] 00007fff37397000 84 rw--- 0000000000000000 000:00000 [ stack ] 00007fff373ec000 4 r-x-- 0000000000000000 000:00000 [ anon ] ffffffffff600000 4 r-x-- 0000000000000000 000:00000 [ anon ] mapped: 4099924K writeable/private: 4096140K shared: 0K [adm-showard@cmhlcarchapp01 ~]$ ps aux | grep 25748 | grep -v grep 8084694 25748 15.6 50.8 4099920 4096392 pts/0 S 14:33 0:03 ./mem
If you comment out the memset() call, you won’t see the RSS memory as high…
[adm-showard@cmhlcarchapp01 ~]$ ps aux | grep 10828 | grep -v grep 8084694 10828 0.0 0.0 4099920 388 pts/0 S 15:13 0:00 ./mem