Re: [Patch 8/8] kexec: allow to shrink reserved memory

[Amerigo Wang <amwang@redhat.com>]

Eric W. Biederman wrote:
> Amerigo Wang <amwang@redhat.com> writes:
>
>   
>> Not that simple, marking it as "__init" means it uses some "__init" data which
>> will be dropped after initialization.
>>     
>
> If we start with the assumption that we will be reserving to much and
> will free the memory once we know how much we really need I see a very
> simple way to go about this. We ensure that the reservation of crash
> kernel memory is done through a normal allocation so that we have
> struct page entries for every page.  On 32bit x86 that is an extra 1MB
> for a 128MB allocation.
>
> Then when it comes time to release that memory we clear whatever magic
> flags we have on the page (like PG_reserve) and call free_page.
>   

Hmm, my MM knowledge is not good enough to judge if this works...
I need to check more MM source code.

Can any MM people help?

Thanks.