Subj : question about the best way to proceed
To   : comp.programming.threads
From : Luke Ehresman
Date : Wed Mar 02 2005 10:59 am

I have a question about the best way to solve a problem.  I'm hoping to
get some feedback from all of you.

I have a multi-threaded application that manages sessions for multiple
users.  There is a thread in the background that does some processing
on all the sessions constantly.  My question is how to best iterate
through the session list in that worker thread.  I can't lock the
session list and hold the lock while I do the processing because there
may be a lot of sessions, and to do all the work on all the sessions
would take a long time (and I would hold the lock for a very long
time).

Let me clarify a bit.  I have two mutexes:  one for the entire session
list, and one for each individual session.  The session list mutex is
used to lock the list when doing operations on the list only.  It is
possible to be working on an individual session, but not hold the lock
to the session list.

Ideally, I would only lock the session I'm currently working with.  But
the problem is that I still need to iterate through all the sessions.
When I finish working with that one session, I don't want to have to
start back at the beginning of the session list (I would never get to
the end!).

Anyone have any thoughts on the best way to solve this?  I have some
ideas but I won't present them just yet because I don't want to taint
your responses with my opinions.

Luke

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