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Config validation was introduced at3aae792bwith main intention to fix infinite purging loop, but it didn't actually fix the underlying problem, just masked it. Later47d69b4eawas merged to address the same problem. Options `hpa_dirty_mult` and `hpa_hugification_threshold` have different application dimensions: `hpa_dirty_mult` applied to active memory on the shard, but `hpa_hugification_threshold` is a threshold for single pageslab (hugepage). It doesn't make much sense to sum them up together. While it is true that too high value of `hpa_dirty_mult` and too low value of `hpa_hugification_threshold` can lead to pathological behaviour, it is true for other options as well. Poor configurations might lead to suboptimal and sometimes completely unacceptable behaviour and that's OK, that is exactly the reason why they are called poor. There are other mechanism exist to prevent extreme behaviour, when we hugified and then immediately purged page, see `hpa_hugify_blocked_by_ndirty` function, which exist to prevent exactly this case. Lastly, `hpa_dirty_mult + hpa_hugification_threshold >= 1` constraint is too tight and prevents a lot of valid configurations.
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: https://jemalloc.net/