8a1a794b0c
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. |
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| bin | ||
| build-aux | ||
| doc | ||
| include | ||
| msvc | ||
| src | ||
| test | ||
| .autom4te.cfg | ||
| .gitattributes | ||
| .gitignore | ||
| autogen.sh | ||
| ChangeLog | ||
| config.stamp.in | ||
| configure.ac | ||
| COPYING | ||
| coverage.sh | ||
| INSTALL | ||
| jemalloc.pc.in | ||
| Makefile.in | ||
| README | ||
jemalloc is a general purpose malloc(3) implementation that emphasizes fragmentation avoidance and scalable concurrency support. jemalloc first came into use as the FreeBSD libc allocator in 2005, and since then it has found its way into numerous applications that rely on its predictable behavior. In 2010 jemalloc development efforts broadened to include developer support features such as heap profiling and extensive monitoring/tuning hooks. Modern jemalloc releases continue to be integrated back into FreeBSD, and therefore versatility remains critical. Ongoing development efforts trend toward making jemalloc among the best allocators for a broad range of demanding applications, and eliminating/mitigating weaknesses that have practical repercussions for real world applications. The COPYING file contains copyright and licensing information. The INSTALL file contains information on how to configure, build, and install jemalloc. The ChangeLog file contains a brief summary of changes for each release. URL: http://www.canonware.com/jemalloc/