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SubjectRe: [PATCH] mm: make free_bootmem to loop bdata_list
On Thu, Mar 13, 2008 at 7:04 PM, KAMEZAWA Hiroyuki
<kamezawa.hiroyu@jp.fujitsu.com> wrote:
> On Thu, 13 Mar 2008 18:39:34 -0700
>
> "Yinghai Lu" <yhlu.kernel@gmail.com> wrote:
>
> > On Thu, Mar 13, 2008 at 6:39 PM, KAMEZAWA Hiroyuki
> > <kamezawa.hiroyu@jp.fujitsu.com> wrote:
> > > On Thu, 13 Mar 2008 11:53:31 -0700
> > > "Yinghai Lu" <yhlu.kernel@gmail.com> wrote:
> > > > ===================================================================
> > > > --- linux-2.6.orig/mm/bootmem.c
> > > > +++ linux-2.6/mm/bootmem.c
> > > > @@ -427,7 +438,9 @@ int __init reserve_bootmem(unsigned long
> > > >
> > > > void __init free_bootmem(unsigned long addr, unsigned long size)
> > > > {
> > > > - free_bootmem_core(NODE_DATA(0)->bdata, addr, size);
> > > > + bootmem_data_t *bdata;
> > > > + list_for_each_entry(bdata, &bdata_list, list)
> > > > + free_bootmem_core(bdata, addr, size);
> > > > }
> > >
> > >
> > > Just a confirmation.
> > > In above loop, boundary check in free_bootmem_core() hits two or more times ?
> > > If yes, it's ok.
> > > If no, please exit loop at hit.
> >
> > yes. need that handle range cross node (RAMDISK case that is end
> > beyond end_of_ram).
> >
> Then, <addr, size> can spread across nodes.
>
> IMHO, there are *big* memory hole between nodes in some systems.
> This kind of interface, which allows alloc/free bootmem accross nodes,
> will see terrible trouble when a programmer assumes "alloc/free bootmem
> always return contiguous size of memory" (This is guaranteed now,)
>
> Does the new allocator (you changed ?) guarantee that returned <address, size>
> is fully contiguous even if it spreads accross nodes ?
>
> If no, NACK for this version.

i didn't change alloc_mem, it still get range from one node and continuous.

new free_bootmem could remove the assumpition in
setup_64.c::setup_arch:free_bootmem about node0
/* Assumes everything on node 0 */
free_bootmem(ramdisk_image, ramdisk_size);
printk(KERN_ERR "initrd extends beyond end of memory "
"(0x%08lx > 0x%08lx)\ndisabling initrd\n",
ramdisk_end, end_of_mem);
initrd_start = 0;

YH


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