Re: shm ?

Dean Gaudet (dgaudet-list-linux-kernel@arctic.org)
Wed, 17 Jun 1998 11:33:31 -0700 (PDT)


Just use IPC_RMID as soon as you have all the handles you need, it won't
actually be deleted until all references go away. We use it in apache
without problem.

If you think the shm stuff is bad, look at the sem stuff. With those you
have to trap all exits from your code and hope some silly admin doesn't
kill -9 (to be fair, this is the same for pthread semaphores, for good
reason in that case). Not to mention that you can't restrict sem's to a
parent-child relationship, so any process running as the same user can
snarf one.

Dean

On Wed, 17 Jun 1998, Mathieu Bouchard wrote:

>
> isn't that pretty much of a documented bug? the user is expected to free
> the shmblocks that an ill-constructed app (like mine) will have left
> behind because of bugs?
>
> taken from man shmctl:
>
> The user must ensure that a segment is eventually
> destroyed; otherwise its pages that were faulted in will
> remain in memory or swap.
>
> however, i have tested the same program under Linux and Solaris, and
> Solaris didn't seem to "lose" memory, while Linux seems to. I have written
> a report on the tests we've done on Linux systems and shm. I should've
> RTFM, because now i know the manpages say it's "normal".
>
> matju
>
>
> -
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.rutgers.edu
>

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu