Memory usage (leak) of iscsiuio and usr/bin/php-cgi

[Website]

1- Would it affect the memory if i just download and upload big files? Not execute them but download and upload them?
2- I think there is a memory leak in usr/bin/php-cgi and based on my research it is pretty common. It uses most of my ram and there are many of them in htop. What would you suggest?
3- One of the biggest memory users is also iscsiuio. What is it and what can i do about it?

[Rubberman]

Linux does a lot of buffering and caching of data into memory, making it look like a lot is being used, which in fact it is not. Cached file data speeds up the system, sometimes dramatically. However, when operating programs need that memory, the OS drops the least-recently accessed data and gives that memory to the operating program that needs it. I have systems with 15-16GB of RAM that consistently show 90-100% memory usage, but the cache/buffer stats (using the 'free' program to view) may accommodate 1/2 of that "used" memory, and in fact, running programs may only account for 30-40% of system memory usage.

So, what can you do about it? Pretty much nothing. The Linux OS is very efficient in its use of memory. You only need to become concerned if you start hitting the swap space on a regular basis, though some advanced software will use that for cache ram as well, so that may be a red-herring, depending upon the software you install. Example, I write software that needs to cache huge amounts of data (distributed web page cache), so I stuff it into shared memory, and that gets swapped out to disc unless accessed. Then the OS swaps it in, and it is then in a memory space that I can access, and I don't need to manage it. The OS takes care of that for me like magic!