[RFC][PATCH 0/2] New API to change the IDs of an existing IPC

[RFC][PATCH 0/2] New API to change the IDs of an existing IPC

[Pierre Peiffer]

Hi,

	As I'm seeing some discussion/interest about IPC, I would like to propose these patches, which provide an easy way to change the ID of an exiting IPC.
This work is done around the checkpoint/restart of applications. In the case of the IPCs, we need (among others) this functionality.

May be there is some other interest about this, so, the RFC concerns both the coding and the interest.

The first patch provide the functionality in kernel side, the second export it in user space. They apply on top of the latest -rc8 kernel. I can adapt them for the latest -mm.

Thanks,

-- 
Pierre

Re: [RFC][PATCH 0/2] New API to change the IDs of an existing IPC

[Michael Kerrisk]

Hi Pierre,

>         As I'm seeing some discussion/interest about IPC, I would like to propose
>  these patches, which provide an easy way to change the ID of an exiting IPC.
> This work is done around the checkpoint/restart of applications. In the case of
> the IPCs, we need (among others) this functionality.

Can you give some more detailed explanation of why this
functionaility is needed.  (Maybe this was explained in other threads,
but if so I've missed it.)

Cheers,

Michael

Re: [RFC][PATCH 0/2] New API to change the IDs of an existing IPC

[Pierre Peiffer]

Michael Kerrisk a écrit :
> Hi Pierre,
> 
>>         As I'm seeing some discussion/interest about IPC, I would like to propose
>>  these patches, which provide an easy way to change the ID of an exiting IPC.
>> This work is done around the checkpoint/restart of applications. In the case of
>> the IPCs, we need (among others) this functionality.
> 
> Can you give some more detailed explanation of why this
> functionaility is needed.  

Sure; in the case of the checkpoint/restart, when you restart an application, what you want is to recreate all system ressources with the same properties they had, when you have checkpointed it.
For IPCs, this means that you need to recreate all the IPCs with the same IDs (at least).
For now, this ID is computed by the system when an IPC is created and you can't specify or modify it.

These patches give you the possibility of changing this ID once the IPC is created.

-- 
Pierre Peiffer