Re: [patch 2/2] bootmem: Node-setup agnostic free_bootmem()

[Johannes Weiner <hannes@saeurebad.de>]

Hi,

"Yinghai Lu" <yhlu.kernel@gmail.com> writes:

> On Sat, Apr 12, 2008 at 3:33 PM, Johannes Weiner <hannes@saeurebad.de> wrote:
>> Make free_bootmem() look up the node holding the specified address
>>  range which lets it work transparently on single-node and multi-node
>>  configurations.
>>
>>  Signed-off-by: Johannes Weiner <hannes@saeurebad.de>
>>  CC: Yinghai Lu <yhlu.kernel@gmail.com>
>>  CC: Andi Kleen <ak@suse.de>
>>  CC: Yasunori Goto <y-goto@jp.fujitsu.com>
>>  CC: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
>>  CC: Ingo Molnar <mingo@elte.hu>
>>  CC: Christoph Lameter <clameter@sgi.com>
>>  CC: Andrew Morton <akpm@linux-foundation.org>
>>  ---
>>
>>  Patch tested on x86_32 uma.
>>
>>  Index: linux-2.6/mm/bootmem.c
>>  ===================================================================
>>  --- linux-2.6.orig/mm/bootmem.c
>>  +++ linux-2.6/mm/bootmem.c
>>  @@ -421,7 +421,15 @@ 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) {
>>  +               if (addr < bdata->node_boot_start)
>>  +                       continue;
>
> could have chance that bootmem with reserved_early that is crossing
> the nodes.

Upstream reserve_bootmem_core() would BUG() on a caller trying to cross
nodes, so I don't see where this chance could come from.

	Hannes