Re: [PATCHv4 6/6] x86/signal: add SA_{X32,IA32}_ABI sa_flags

[Oleg Nesterov]

On 09/01, Dmitry Safonov wrote:
>
> And the biggest problem in this approach would be not the size of
> code changes to CRIU (which are already quite large with this
> patches set), but AFAICS, it will have big performance penalty:
> we would need to bounce process tree, processes properties
> from parent-CRIU to child-CRIU after exec() call and down on
> the processes hierarchy, recreating processes while synchronizing
> process's data from images.
>
> As for now, we already have time-critical problems in ÐRIU and
> we try to reduce the number of system calls, while it's still slow
> at some places. But that approach will lead to:
> o exec different CRIU
> o initialize it (i.e, parse /proc/self/maps to know it's vmas)
> o transphere process tree, for each process it's properties with IPC
>    after exec()
> It will all go for a large number of syscalls in total.

I do not really understand why it has to be so complicated, but
I can be easily wrong.

> And this arch_prctl() API is visible under CHECKPOINT_RESTORE
> config option, so will not bother anyone.

I mostly dislike 6/6. This new feauture looks a bit strange to me.

Nevermind, let me repeat once again, I am not trying to argue with
this series. No objections from me.

Oleg.