void pcre2_jit_free_unused_memory(pcre2_general_context *gcontext);
This function frees unused JIT executable memory. The argument is a general context, for custom memory management, or NULL for standard memory management. JIT memory allocation retains some memory in order to improve future JIT compilation speed. In low memory conditions, pcre2_jit_free_unused_memory() can be used to cause this memory to be freed.
There is a complete description of the PCRE2 native API in the pcre2api page and a description of the POSIX API in the pcre2posix page.