On Thu, 2010-08-26 at 04:40 +0200, Michał Nazarewicz wrote:
quoted text
> I think that the biggest problem is fragmentation here.  For instance,
> I think that a situation where there is enough free space but it's
> fragmented so no single contiguous chunk can be allocated is a serious
> problem.  However, I would argue that if there's simply no space left,
> a multimedia device could fail and even though it's not desirable, it
> would not be such a big issue in my eyes.
> 
> So, if only movable or discardable pages are allocated in CMA managed
> regions all should work well.  When a device needs memory discardable
> pages would get freed and movable moved unless there is no space left
> on the device in which case allocation would fail. 

If you'd actually looked at the page allocator you'd see its capable of
doing exactly that!

I has the notion of movable pages, it can defragment free space (called
compaction).

Use it!
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