Re: [patch 4/6] mm: merge populate and nopage into fault (fixes nonlinear)

Bill Irwin
2007-03-07T09:29:35Z

On Wed, 7 Mar 2007 09:27:55 +0100 Ingo Molnar <mingo@elte.hu> wrote:
>> btw., if we decide that nonlinear isnt worth the continuing maintainance
>> pain, we could internally implement/emulate sys_remap_file_pages() via a
>> call to mremap() and essentially deprecate it, without breaking the ABI
>> - and remove all the nonlinear code. (This would split fremap areas into
>> separate vmas)

On Wed, Mar 07, 2007 at 12:35:20AM -0800, Andrew Morton wrote:
> I'm rather regretting having merged it - I don't think it has been used for
> much.
> Paolo's UML speedup patches might use nonlinear though.

Guess what major real-life application not only uses nonlinear daily
but would even be very happy to see it extended with non-vma-creating
protections and more? It's not terribly typical for things to be
truncated while remap_file_pages() is doing its work, though it's been
proposed as a method of dynamism. It won't stress remap_file_pages() vs.
truncate() in any meaningful way, though, as userspace will be rather
diligent about clearing in-use data out of the file offset range to be
truncated away anyway, and all that via O_DIRECT.

-- wli