Re: [PATCH] memblock: Make sure reserved.regions is freed really
From: Yinghai Lu
Date: Mon Jun 18 2012 - 19:46:35 EST
On Mon, Jun 18, 2012 at 4:09 PM, Tejun Heo <tj@xxxxxxxxxx> wrote:
> Hey, Yinghai.
>
> On Mon, Jun 18, 2012 at 03:58:52PM -0700, Yinghai Lu wrote:
>> > Hmmm... nice catch but I think it's a bit complex and ugly. In this
>> > case, we *know* that the region isn't gonna be split. Maybe a better
>> > option is to add something like the following?
>>
>> how do you know __pa(memblock.reserved.regions) would not be merged
>> with other entries
>> in reserved.regions?
>>
>> >
>> > void memblock_remove_region_by_ptr(struct memblock_type *type,
>> > struct memblock_region *r)
>> > {
>> > WARN_ON(/* make sure @r is inside @type->regions */);
>> > memblock_remove_region(type, r - type->regions);
>> > }
>>
>> you want to change
>
> Heh, you're right. My suggestion was completely bonkers. Sorry about
> that. Hmm.... how about separating out removal pre-expansion and
> doing it before calling into free? ie. something like
>
> static int memblock_prepare_for_isolation(struct memblock_type *type)
> {
> /* we'll create at most two more regions */
> while (type->cnt + 2 > type->max)
> if (memblock_double_array(type) < 0)
> return -ENOMEM;
> return 0;
> }
>
> int __init_memblock memblock_free_reserved_regions(void)
> {
> int ret;
>
> if (memblock.reserved.regions == memblock_reserved_init_regions)
> return 0;
>
> ret = memblock_prepare_for_isolation(&memblock.reserved);
> if (ret)
> return ret;
>
> ret = memblock_free(__pa(memblock.reserved.regions),
> sizeof(struct memblock_region) * memblock.reserved.max);
> WARN_ON(ret || memblock.reserved.regions has changed);
> return ret;
> }
yes. that looks good. but that WARN_ON looks wrong, could just drop that line.
Please send complete version to Andrew or Linus.
Thanks
Yinghai
--
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/