John Stultz wrote:
> On 01/27/2014 04:12 PM, Minchan Kim wrote:
>> On Mon, Jan 27, 2014 at 05:23:17PM -0500, KOSAKI Motohiro wrote:
>>> - Your number only claimed the effectiveness anon vrange, but not file vrange.
>> Yes. It's really problem as I said.
>>  From the beginning, John Stultz wanted to promote vrange-file to replace
>> android's ashmem and when I heard usecase of vrange-file, it does make sense
>> to me so that's why I'd like to unify them in a same interface.
>>
>> But the problem is lack of interesting from others and lack of time to
>> test/evaluate it. I'm not an expert of userspace so actually I need a bit
>> help from them who require the feature but at a moment,
>> but I don't know who really want or/and help it.
>>
>> Even, Android folks didn't have any interest on vrange-file.
>
> Just as a correction here. I really don't think this is the case, as
> Android's use definitely relies on file based volatility. It might be
> more fair to say there hasn't been very much discussion from Android
> developers on the particulars of the file volatility semantics (out
> possibly not having any particular objections, or more-likely, being a
> bit too busy to follow the all various theoretical tangents we've
> discussed).
>
> But I'd not want anyone to get the impression that anonymous-only
> volatility would be sufficient for Android's needs.
Mozilla is starting to use android's ashmem for discardable memory 
within a single process: 
https://bugzilla.mozilla.org/show_bug.cgi?id=748598 .

Volatile ranges do help with that specific(uncommon?) use of ashmem.

For Mozilla sharing memory across processes via ashmem is not a nearterm 
project. It's something that is likely to require significant rework. 
Process-local discardable memory can be retrofited in a more 
straight-forward fashion.

Taras