linux-kernel - Re: Config NO_BOOTMEM breaks my amd64 box

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Message-ID: <4BB3D0F4.902@kernel.org>
Date:	Wed, 31 Mar 2010 15:47:16 -0700
From:	Yinghai Lu <yinghai@...nel.org>
To:	Ingo Molnar <mingo@...e.hu>
CC:	James Morris <jmorris@...ei.org>, "H. Peter Anvin" <hpa@...or.com>,
	linux-kernel@...r.kernel.org, airlied@...ux.ie
Subject: Re: Config NO_BOOTMEM breaks my amd64 box

On 03/31/2010 03:41 PM, Ingo Molnar wrote:
> 
> * Yinghai Lu <yinghai@...nel.org> wrote:
> 
>> On 03/31/2010 03:13 PM, Ingo Molnar wrote:
>>>
>>> * Yinghai Lu <yinghai@...nel.org> wrote:
>>>
>>>> --- linux-2.6.orig/arch/x86/mm/init_32.c
>>>> +++ linux-2.6/arch/x86/mm/init_32.c
>>>> @@ -875,7 +875,12 @@ void __init mem_init(void)
>>>>  	BUG_ON(!mem_map);
>>>>  #endif
>>>>  	/* this will put all low memory onto the freelists */
>>>> +#if defined(CONFIG_NO_BOOTMEM) && defined(MAX_NUMNODES)
>>>> +	/* In case some 32bit systems don't have RAM installed on node0 */
>>>> +        totalram_pages += free_all_memory_core_early(MAX_NUMNODES);
>>>
>>> (Note: tab whitespace damage)
>>>
>>>> +#else
>>>>  	totalram_pages += free_all_bootmem();
>>>
>>> So we get into this branch if CONFIG_NO_BOOTMEM is enabled but MAX_NUMNODES is 
>>> not defined? Doesnt look right.
>>
>> yes. 
>>
>> free_all_bootmem() will call
>> free_all_memory_core_early(NODE_DATA(0)->node_id);
>>
>> Thanks
> 
> Well and that whole #ifdeffery is disgusting as well - even if the goal was to 
> remove CONFIG_NO_BOOTMEM ASAP.
> 
> Please learn to use proper intermediate helper functions and at minimum put 
> the conversion ugliness somewhere that doesnt intrude our daily flow in .c 
> files. The best rule is to _never ever_ put an #ifdef construct into a .c 
> file. It doesnt matter what the goal if the #ifdef is - such ugliness in code 
> is never justified.
> 

if you agree that i can have one nobootmem.c in mm/

Thanks

Yinghai
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