help sharing shared memory between non sibling processes
Typically an application allocates shared memory, and then calls fork()
to create 1 or more child processes which then are able to share that
shared memory segment. I have a requirement for non sibling processes
which need to share items in shared memory. I am not familiar with any
solutions in this area. Below is a very brief outline of my approach,
I would greatly appreciate pointers to existing work or discussion about
- Maintain a "catalog" of items and the shared memory ID that the items
are stored in.
- Operations on the catalog are as follows:
- add item
- delete item
- query items in catalog
- request a read/write lock to an item
- request a read only lock to an item
- release a lock
- initialize / terminate
- I realize I could have a client/server or client side only approach.
Currently, I am leaning toward a client side only solution where I maintain
the catalog in shared memory, with 1 semaphore that controls access to
the catalog data (it provides the necessary locking for adds/deletes...).
- The first process up would actually initialize the empty catalog, others
would simply connect to it, and execute transactions.
- For the most part, the access patterns will be very low-bandwidth, e.g.
a process comes up, requests data is shared memory, and then releases
that data upon it termination -- I realize that the single semaphore
would be a major bottle neck if a process was locking/unlocking... with
a high frequency.
If you have seen work in this area, please let me know.
John Love, jl...@lgc.com
Landmark Graphics Houston, TX