Re: [PATCH 13/12] ksm: fix munlock during exit_mmap deadlock

[Izik Eidus <ieidus@redhat.com>]

Hugh Dickins wrote:
>
> It may be that MADV_UNMERGEABLE isn't really needed (I think I even
> admitted once that probably nobody would use it other than we testing
> it).  Yet I hesitate to rip it out: somehow it still seems right to
> have it in there.  Why did you have unregistering in the /dev/ksm KSM?
>   

It was more to give possiblaty to applications save cpu cycles of ksmd 
so it wont continue to scan memory regions that don`t need ksm anymore,
As you said if someone will ever use it?, have no idea...

>   
> I didn't seem idiotic to me, but I hadn't realized the ksmd timelapse
> uncertainty Andrea points out.  Well, I'm not keen to change the way
> it's working at present, but I do think you're right to question all
> these aspects of unmerging.
>   

Yes lets keep it like that, UNMERGEABLE sound anyway like something that 
going to break the pages..., we can always add later STOPMERGE as a call 
that tell ksm to stop merge the pages but not break the shared pages...

> Hugh
>