Re: [PATCH] 2/2 Prezeroing large blocks of pages during allocation Version 4

[KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>]

Mel Gorman wrote:

>>>      
>>>
>>Now, 5bits per  MAX_ORDER pages.
>>I think it is simpler to use "char[]" for representing type of  memory alloc
>>type than bitmap.
>>
>>    
>>
>
>Possibly, but it would also use up that bit more space. That map could be
>condensed to 3 bits but would make it that bit (no pun) more complex and
>difficult to merge. On the other hand, it would be faster to use a char[]
>as it would be an array-index lookup to get a pageblock type rather than a
>number of bit operations.
>
>So, it depends on what people know to be better in general because I have
>not measured it to know for a fact. Is it better to use char[] and use
>array indexes rather than bit operations or is it better to leave it as a
>bitmap and condense it later when things have settled down?
>  
>
Hmm, Okay, I'll wait for condensed version.
BTW, in space consumption/cache view,  does using bitmap have  real 
benefit   ?

Thanks
-- Kame <kamezawa.hiroyu@jp.fujitsu.com>