Re: [PATCH 2/6] memblock: Introduce bottom-up allocation mode

[Zhang Yanfei]

On 09/24/2013 10:16 PM, Tejun Heo wrote:
> Hello,
> 
> On Tue, Sep 24, 2013 at 10:12:22PM +0800, Zhang Yanfei wrote:
>> I see. I think it is rarely to fail. But here is case that it must
>> fail in the current bottom-up implementation. For example, we allocate
>> memory in reserve_real_mode() by calling this: 
>> memblock_find_in_range(0, 1<<20, size, PAGE_SIZE);
>>
>> Both the start and end is below the kernel, so trying bottom-up for
>> this must fail. So I am now thinking that if we should take this as
>> the special case for bottom-up. That said, if we limit start and end
>> both below the kernel, we should allocate memory below the kernel instead
>> of make it fail. The cases are also rare, in early boot time, only
>> these two:
>>
>>  |->early_reserve_e820_mpc_new()   /* allocate memory under 1MB */
>>  |->reserve_real_mode()            /* allocate memory under 1MB */
>>
>> How do you think?
> 
> They need to be special cased regardless, right?  It's wrong to print
> out warning messages for things which are expected to behave that way.
> Just skip bottom-up allocs if @end is under kernel image?
> 

Good idea. Will do this way.

-- 
Thanks.
Zhang Yanfei
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