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When using metadata_thp, allocate tcache bin stacks from base0, which means they will be placed on huge pages along with other metadata, instead of mixed with other regular allocations. In order to do so, modified the base allocator to support limited reuse: freed tcached stacks (from thread termination) will be returned to base0 and made available for reuse, but no merging will be attempted since they were bump allocated out of base blocks. These reused base extents are managed using separately allocated base edata_t -- they are cached in base->edata_avail when the extent is all allocated. One tricky part is, stats updating must be skipped for such reused extents (since they were accounted for already, and there is no purging for base). This requires tracking the "if is reused" state explicitly and bypass the stats updates when allocating from them.
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/