On Fri, 20 Aug 2010 15:15:10 +0200, Peter Zijlstra [off-list ref] wrote:

So the idea is to grab a large chunk of memory at boot time and then
later allow some device to use it?

I'd much rather we'd improve the regular page allocator to be smarter
about this. We recently added a lot of smarts to it like memory
compaction, which allows large gobs of contiguous memory to be freed for
things like huge pages.

If you want guarantees you can free stuff, why not add constraints to
the page allocation type and only allow MIGRATE_MOVABLE pages inside a
certain region, those pages are easily freed/moved aside to satisfy
large contiguous allocations.

I'm aware that grabbing a large chunk at boot time is a bit of waste of
space and because of it I'm hoping to came up with a way of reusing the
space when it's not used by CMA-aware devices.  My current idea was to
use it for easily discardable data (page cache?).

Also, please remove --chain-reply-to from your git config. You're using
1.7 which should do the right thing (--no-chain-reply-to) by default.

OK.

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