2009/1/15 Matt Sealey <matt@genesi-usa.com>:
Actually it doesn't really use much memory at all! Because it's a demand paged virtual memory system, not one using "swapping", and furthermore those pages can be shared amongst many processes thanks to COW.
Sorry Rob, but whether it's in physical memory or in swap it's still loaded, it's still taking up some part of my address space.
You would nitpick about the term swap. Linux calls it swap, as badly named as it might be, it's still swap space in this terminology, and a page pushed out to disk is still a page allocated in the system. If you have a 4GB address space to use and you have 3GB of it out on disk, you still only have 1GB left whether you can fit more in physical memory or not.
Once again!! The program text segment pages are read only, they are not dirty, they are not saved to disk, because they already exist in the file system. Your on-disk copy is memory mapped in. Some embedded providers in past, using Flash or Proms instead of disk, have made kernel alterations, to run from their memory directly, rather than copy the page into RAM. Abuse and patronise me all you like, but some time spent studying VM issues, might help your low RAM system. Increasing the swappiness factor, as per Andrew Morton's view point, will save you some memory. Not huge amounts, but it'll be more signicant than whether the kernel loaded device mapper or not. -- To unsubscribe, e-mail: opensuse-factory+unsubscribe@opensuse.org For additional commands, e-mail: opensuse-factory+help@opensuse.org