Anyway to refresh the memory usage in Linux Server ?

I have installed 1 GB ram in my Linux Server , but it is not public yet . but it already used 4xx Mb .

When i reboot the server , it just show 7x mb memory usage in system ...



Do i need to refresh a memory usage in a schedule time ?

Its normal for linux to use up available ram if needed. Most of it is just held but not used, reserved for future use. Its the way it all works. If your still concerned. Run MemTest86 a few time and perhaps replace the ram. I don't think you need to take such drastic action however, you're probably just fine and freaking out over nothing.

so many daemons have already forked several children for future use, to reduce time for memory allocation for each request, those fokred children are mostly idle and use up no CPU resource, so if you see 3xx M ram being used its most likely only 1xx M is used by actively running processes, there should be some configuration you can do to reduce idle processes from taking up memory, but your cpu load may jump up a bit

Usually apache memory usage increases with time.

It is not necessary to free up memory because, as it was said the system uses it for caching. More memory used for cache means less CPU load.

I assume apache is taking a big part of this RAM so I'll give you a tip. If you don't run apache then simply ignore me.

For example try to set
"MaxRequestsPerChild" in your httpd.conf to very low number - 10 or 20. It will kill apache processes often and free up some RAM.
However the server load will rise a bit.