[mythtv-users] how to make 0.24 more like 0.21 ?

Eric Sharkey eric at lisaneric.org
Wed Oct 26 19:44:11 UTC 2011


On Wed, Oct 26, 2011 at 3:32 PM, Roger Horner <mythtvuser1818 at gmail.com> wrote:
> My question is why would it use swap space if there is a buffer
> cache?

It keeps in RAM the information that it thinks is most likely to be
needed.  Many times an application might allocate memory which it
doesn't actually use.  Perhaps a process forks and the child process
hasn't freed memory allocated by the parent, but the parent modifies
this data?  The original version has to live somewhere since the child
might reference it.  The kernel might decide it is advantageous to
swap out this probably unnecessary memory in favor of the buffer cache
since the filesystem data might actually be more likely to need to be
re-read first.

Figuring out what to swap and what to keep is a hideously complicated black art.

Eric


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