server-skynet-source-3rd-je.../include/jemalloc
Elliot Ronaghan 5acef864f2 Don't use compact red-black trees with the pgi compiler
Some bug (either in the red-black tree code, or in the pgi compiler) seems to
cause red-black trees to become unbalanced. This issue seems to go away if we
don't use compact red-black trees. Since red-black trees don't seem to be used
much anymore, I opted for what seems to be an easy fix here instead of digging
in and trying to find the root cause of the bug.

Some context in case it's helpful:

I experienced a ton of segfaults while using pgi as Chapel's target compiler
with jemalloc 4.0.4. The little bit of debugging I did pointed me somewhere
deep in red-black tree manipulation, but I didn't get a chance to investigate
further. It looks like 4.2.0 replaced most uses of red-black trees with
pairing-heaps, which seems to avoid whatever bug I was hitting.

However, `make check_unit` was still failing on the rb test, so I figured the
core issue was just being masked. Here's the `make check_unit` failure:

```sh
=== test/unit/rb ===
test_rb_empty: pass
tree_recurse:test/unit/rb.c:90: Failed assertion: (((_Bool) (((uintptr_t) (left_node)->link.rbn_right_red) & ((size_t)1)))) == (false) --> true != false: Node should be black
test_rb_random:test/unit/rb.c:274: Failed assertion: (imbalances) == (0) --> 1 != 0: Tree is unbalanced
tree_recurse:test/unit/rb.c:90: Failed assertion: (((_Bool) (((uintptr_t) (left_node)->link.rbn_right_red) & ((size_t)1)))) == (false) --> true != false: Node should be black
test_rb_random:test/unit/rb.c:274: Failed assertion: (imbalances) == (0) --> 1 != 0: Tree is unbalanced
node_remove:test/unit/rb.c:190: Failed assertion: (imbalances) == (0) --> 2 != 0: Tree is unbalanced
<jemalloc>: test/unit/rb.c:43: Failed assertion: "pathp[-1].cmp < 0"
test/test.sh: line 22: 12926 Aborted
Test harness error
```

While starting to debug I saw the RB_COMPACT option and decided to check if
turning that off resolved the bug. It seems to have fixed it (`make check_unit`
passes and the segfaults under Chapel are gone) so it seems like on okay
work-around. I'd imagine this has performance implications for red-black trees
under pgi, but if they're not going to be used much anymore it's probably not a
big deal.
2016-09-26 11:08:45 -07:00
..
internal Don't use compact red-black trees with the pgi compiler 2016-09-26 11:08:45 -07:00
jemalloc_defs.h.in Detect LG_SIZEOF_PTR depending on MSVC platform target 2016-02-20 10:50:24 -08:00
jemalloc_macros.h.in Add (size_t) casts to MALLOCX_ALIGN(). 2016-03-11 10:11:56 -08:00
jemalloc_mangle.sh Fix name mangling for stress tests. 2014-01-16 17:38:01 -08:00
jemalloc_protos.h.in Add JEMALLOC_CXX_THROW to the memalign() function prototype. 2015-08-26 13:47:20 -07:00
jemalloc_rename.sh Fix name mangling for stress tests. 2014-01-16 17:38:01 -08:00
jemalloc_typedefs.h.in Implement chunk hook support for page run commit/decommit. 2015-08-07 00:50:58 -07:00
jemalloc.sh Remove extraneous ';' on closing 'extern "C"' 2015-07-16 11:37:19 +01:00