On Tue, 11 Sep 2007, J=F6rn Engel wrote:

quoted text
> While I agree with your concern, those numbers are quite silly.  The
> chances of 99.8% of pages being free and the remaining 0.2% being
> perfectly spread across all 2MB large_pages are lower than those of SHA1
> creating a collision.  I don't see anyone abandoning git or rsync, so
> your extreme example clearly is the wrong one.
>=20
> Again, I agree with your concern, even though your example makes it look
> silly.

You may want to consider Mel's antifrag approaches which certainly=20
decreases the chance of this occurring. Reclaim can open up the needed=20
linear memory hole in a intentional way. The memory compaction approach=20
can even move pages to open up these 2M holes. The more pages we make=20
movable (see f.e. the targeted slab reclaim patchset that makes slab=20
pages movable) the more reliable higher order allocations become.