Re: [RFC:Patch: 000/008](memory hotplug) rough idea of pgdat removing

[Christoph Lameter]

Yasunori Goto wrote:

> I thought it at first, but are there the following worst case?
> 
> 
>    CPU 0                                    CPU 1
> -------------------------------------------------------
> __alloc_pages()
>     
>     parsing_zonelist()
>         :
>     enter page_reclarim()
>     sleep (and remember zone)                 :
>                                               :
>                                         update zonelist and node_online_map
>                                           with stop_machine_run()
>                                         free pgdat().
>                                         remove the Node electrically.
> 
>     wake up and touch remembered
>        zone,  but it is removed
>     (Oops!!!)
> 
> 
> 
> Anyway, I'm happy if there is better way than my poor idea. :-)
> 
> Thanks for your comment.

Duh. Then the use of RCU would also mean that all of reclaim must be in a rcu period. So  reclaim cannot sleep anymore.



--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/