Messages in this thread | | | Date | Tue, 18 Aug 2009 09:29:39 +0900 | From | KAMEZAWA Hiroyuki <> | Subject | Re: [Patch 8/8] kexec: allow to shrink reserved memory |
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On Mon, 17 Aug 2009 17:50:21 +0800 Amerigo Wang <amwang@redhat.com> wrote:
> 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? > Hm, memory-hotplug guy is here.
Can I have a question ?
- How crash kernel's memory is preserved at boot ? It's hidden from the system before mem_init() ?
Thanks, -Kame
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