Convert the production source files in src/ (69 .c/.cpp) and
test/jemalloc_test.h.in to list the headers they actually use, then
delete the umbrella. Three consolidated headers (peak_event.h,
prof_sys.h, sz.h) also gain explicit transitive includes.
Every translation unit now declares what it uses. A missing include
now fails at the failing file rather than silently working because
something upstream pulled in the world.
As pointed out in #2434, the thread_name in prof_tdata_t was changed in #2407.
This also requires an update for the prof_recent dump, specifically the emitter
expects a "char **" which is fixed in this commit.
The previous approach managed the thread name in a separate buffer, which causes
races because the thread name update (triggered by new samples) can happen at
the same time as prof dumping (which reads the thread names) -- these two
operations are under separate locks to avoid blocking each other. Implemented
the thread name storage as part of the tdata struct, which resolves the lifetime
issue and also avoids internal alloc / dalloc during prof_sample.
This hints to the compiler that it should care more about space than CPU (among
other things). In cases where the compiler lacks profile-guided information,
this can be a substantial space savings.
For now, we mark the mallctl or atexit driven profiling and stats functions that
take up the most space.
