pgsql: pg_buffercache: Allow huge allocations.

pg_buffercache: Allow huge allocations.

Otherwise, users who have configured shared_buffers >= 256GB won't
be able to use this module.  There probably aren't many of those, but
it doesn't hurt anything to fix it so that it works.

Backpatch to 9.4, where MemoryContextAllocHuge was introduced.  The
same problem exists in older branches, but there's no easy way to
fix it there.

KaiGai Kohei

Branch
------
REL9_4_STABLE

Details
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http://git.postgresql.org/pg/commitdiff/1336bd9862c15db20a879f27082d18604fec7093

Modified Files
--------------
contrib/pg_buffercache/pg_buffercache_pages.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)