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

[Benjamin Herrenschmidt <benh@kernel.crashing.org>]

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 :-)

Cheers,
Ben.


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