Re: mm: convert vma->vm_flags to 64bit

From: Nai Xia
Date: Fri Nov 11 2011 - 03:38:24 EST


On Fri, Nov 11, 2011 at 12:31 PM, Benjamin Herrenschmidt
<benh@xxxxxxxxxxxxxxxxxxx> wrote:
> On Thu, 2011-11-10 at 18:09 -0800, Hugh Dickins wrote:
>> It was in this mail below, when Andrew sent Linus the patch, and Linus
>> opposed my "argument" in support: that wasn't on lkml or linux-mm,
>> but I don't see that its privacy needs protecting.
>>
>> KOSAKI-san then sent instead a patch to correct some ints to longs,
>> which Linus did put in: but changing them to a new "vm_flags_t".
>>
>> He was, I think, hoping that one of us would change all the other uses
>> of unsigned long vm_flags to vm_flags_t; but in fact none of us has
>> stepped up yet - yeah, we're still sulking that we didn't get our
>> shiny new 64-bit vm_flags ;)
>>
>> I think Linus is not opposed to PowerPC and others defining a 64-bit
>> vm_flags_t if you need it, but wants not to bloat the x86_32 vma.
>>
>> I'm still wary of the contortions we go to in constraining flags,
>> and feel that the 32-bit case holds back the 64-bit, which would
>> not itself be bloated at all.
>>
>> The subject is likely to come up again, more pressingly, with page
>> flags.
>
> Right, tho the good first step is to convert everything to vm_flags_t so
> we can easily switch if we want to, even on a per-arch basis...
>
> Oh well, now all we need is a volunteer :-)

Maybe a "Kernel Common Resource Authority" is needed for all similar
requests, just like IANA for IP addresses... :)


Thanks,
Nai
>
> Cheers,
> Ben.
>
>
>
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