Processes in Shared Memory


 
Thread Tools Search this Thread
Top Forums Shell Programming and Scripting Processes in Shared Memory
# 1  
Old 10-23-2009
Processes in Shared Memory

Hello ,

I would like to know how to check if a given process id belongs to particualr shared memory segment .

Please help

Thanks in advance
# 2  
Old 10-23-2009
A shared memory segment is not owned by a process but rather is pinned in memory and is owned by a user / group. Multiple processes can access the shared memory segments with the right credentials. You can check the segment and who owns them by typing:
Code:
ipcs -ma

as user root.
# 3  
Old 10-23-2009
Yes I realized

I realized that the CPID is the creator process id and from there I could
trace all the active processes that are accessing a particular shared memory segment.
# 4  
Old 10-23-2009
I see... I would tend to think that from a process' perspective it is not relevant who the CPID is. To find out who are using a shared memory segment I would look at the processes and see what regions they have mapped using a utility like e.g. pmap and/or perhaps info in /proc/pid if you are on a linux system.
Login or Register to Ask a Question

Previous Thread | Next Thread

10 More Discussions You Might Find Interesting

1. Programming

Shared library with acces to shared memory.

Hello. I am new to this forum and I would like to ask for advice about low level POSIX programming. I have to implement a POSIX compliant C shared library. A file will have some variables and the shared library will have some functions which need those variables. There is one special... (5 Replies)
Discussion started by: iamjag
5 Replies

2. Homework & Coursework Questions

processes and shared memory

Hi again! I have 2 questions ..: How can i create exactly one number of processes ? For example i want to create l*n processes and i tried this: for(i=0;i<l*n;i++){ pid=fork()} But it creates more than l*n Also, i want each child to run another x.c program with 3 command line... (1 Reply)
Discussion started by: giampoul
1 Replies

3. Homework & Coursework Questions

processes and shared memory

Hi again! I have 2 questions ..: How can i create exactly one number of processes ? For example i want to create l*n processes and i tried this: for(i=0;i<l*n;i++){ pid=fork()} But it creates more than l*n Also, i want each child to run another x.c program with 3 command line... (1 Reply)
Discussion started by: giampoul
1 Replies

4. Shell Programming and Scripting

Parallel processes to INC- and DEC-rement shared counter

QUESTION: How do I run processes in parallel, so that the counter (in counter.txt) would vary in value (instead of just "0" and "1")? That is, how to not sequentially run inc.sh and dec.sh? The shared counter (a single number starting as 0) is in a file counter.txt. counter.sh is (supposed to... (2 Replies)
Discussion started by: courteous
2 Replies

5. UNIX for Advanced & Expert Users

AIX: Finding processes attached to shared memory

Is there some way to tell what processes are attached to a shared memory segment? We have a system on which I perform "icps -ma" and there are several segments pending deletion having numerous processes attached to them and I can't tell what processes they are. Neither the creator's pid nor last... (7 Replies)
Discussion started by: DreamWarrior
7 Replies

6. Programming

Shared memory for shared library

I am writing a shared library in Linux (but compatible with other UNIXes) and I want to allow multiple instances to share a piece of memory -- 1 byte is enough. What's the "best" way to do this? I want to optimize for speed and portability. Obviously, I'll have to worry about mutual exclusion. (0 Replies)
Discussion started by: otheus
0 Replies

7. Programming

Shared memory in shared library

I need to create a shared library to access an in memory DB. The DB is not huge, but big enough to make it cumbersome to carry around in every single process using the shared library. Luckily, it is pretty static information, so I don't need to worry much about synchronizing the data between... (12 Replies)
Discussion started by: DreamWarrior
12 Replies

8. Programming

memory sharing - not shared memory -

hi, this is the problem: i want to swap a linked list between 4 processes (unrelated), is there any way i can do that just by sending a pointer to a structure? //example typedef struct node { int x; char c; struct node *next; } node; or i should send the items ( x,c ) by... (9 Replies)
Discussion started by: elzalem
9 Replies

9. Programming

how to view loaded shared libraries by running processes in linux

anybody knows how to view loaded shared libraries by running processes in linux enviornment? any command or tool ? thanks a lot (3 Replies)
Discussion started by: princelinux
3 Replies

10. UNIX for Advanced & Expert Users

Shared memory shortage but lots of unused memory

I am running HP-UX B.11.11. I'm increasing a parameter for a database engine so that it uses more memory to buffer the disk drive (to speed up performance). I have over 5GB of memory not being used. But when I try to start the DB with the increased buffer parameter I get told. "Not... (1 Reply)
Discussion started by: cjcamaro
1 Replies
Login or Register to Ask a Question