| Re: [RFC][PATCH 2/2] Virtualization of IPC [message #2210 is a reply to message #2200] |
Fri, 24 March 2006 20:09   |
ebiederm
Messages: 1354
Registered: February 2006
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Senior Member |
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Kirill Korotaev <dev@sw.ru> writes:
> This patch introduces IPC namespaces, which allow to create isolated IPC users
> or containers.
> Introduces CONFIG_IPC_NS and ipc_namespace structure.
> It also uses current->ipc_ns as a pointer to current namespace, which reduces
> places where additional argument to functions should be added.
I don't see where we are freeing the shared memory segments,
the message queues and the semaphores when the last user of the namespace
goes away. Am I missing something?
> --- a/include/linux/ipc.h
> +++ b/include/linux/ipc.h
> @@ -70,6 +70,50 @@ struct kern_ipc_perm
>
> #endif /* __KERNEL__ */
>
> +#include <linux/config.h>
> +
> +#ifdef CONFIG_IPC_NS
> +#include <asm/atomic.h>
> +
> +struct ipc_ids;
> +struct ipc_namespace {
> + atomic_t cnt;
> +
> + struct ipc_ids *sem_ids;
> + int sem_ctls[4];
> + int used_sems;
> +
> + struct ipc_ids *msg_ids;
> + int msg_ctlmax;
> + int msg_ctlmnb;
> + int msg_ctlmni;
> +
> + struct ipc_ids *shm_ids;
> + size_t shm_ctlmax;
> + size_t shm_ctlall;
> + int shm_ctlmni;
> + int shm_total;
> +};
I believe there is a small problem with this implementation.
per namespace counts and limits are fine. But I think we want
to maintain true global limits as well. I know
concerns of that nature have been expressed in regards
to Daves patch.
> --- a/kernel/fork.c
> +++ b/kernel/fork.c
> @@ -1193,6 +1193,7 @@ static task_t *copy_process(unsigned lon
> attach_pid(p, PIDTYPE_TGID, p->tgid);
> attach_pid(p, PIDTYPE_PID, p->pid);
> get_uts_ns(p->uts_ns);
> + get_ipc_ns(p->ipc_ns);
>
> nr_threads++;
> total_forks++;
Again please move the get outside of the tasklist_lock.
Eric
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