Fix spinlock implementation for some !solaris sparc platforms.
Some Sparc CPUs can be run in various coherence models, ranging from
RMO (relaxed) over PSO (partial) to TSO (total). Solaris has always
run CPUs in TSO mode while in userland, but linux didn't use to and
the various *BSDs still don't. Unfortunately the sparc TAS/S_UNLOCK
were only correct under TSO. Fix that by adding the necessary memory
barrier instructions. On sparcv8+, which should be all relevant CPUs,
these are treated as NOPs if the current consistency model doesn't
require the barriers.
Discussion: 20140630222854.GW26930@awork2.anarazel.de
Will be backpatched to all released branches once a few buildfarm
cycles haven't shown up problems. As I've no access to sparc, this is
blindly written.
Branch
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REL9_4_STABLE
Details
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http://git.postgresql.org/pg/commitdiff/11687e728d726a8ab3c9e165e4f7d962013f46ab
Modified Files
--------------
src/backend/port/tas/sunstudio_sparc.s | 2 ++
src/include/storage/s_lock.h | 49 +++++++++++++++++++++++++++++++-
2 files changed, 50 insertions(+), 1 deletion(-)