This is useful for our internal builds where we override the configuration in the header files generated by autoconf.
None of these are harmful, and they are almost certainly optimized away by the compiler. The motivation for fixing them anyway is that we'd like to enable static analysis as part of CI, and the first step towards that is resolving the warnings it produces at present.
and use it on the background thread name setting.
The codebase is already very disciplined in making any function which can be `static`, but there are a few that appear to have slipped through the cracks.
`edata_cmp_summary_comp` is one of the very hottest functions, taking up 3% of all time spent inside Jemalloc. I noticed that all existing callsites rely only on the sign of the value returned by this function, so I came up with this equivalent branchless implementation which preserves this property. After empirical measurement, I have found that this implementation is 30% faster, therefore representing a 1% speed-up to the allocator as a whole. At @interwq's suggestion, I've applied the same optimization to `edata_esnead_comp` in case this function becomes hotter in the future.
As a hint flag of the lock, parameter locked should be set only when the lock is gained or freed.
Decay should not be triggered during reentrant calls (may cause lock order reversal / deadlocks). Added a delay_trigger flag to the tickers to bypass decay when rentrancy_level is not zero.
This lowered the sizeof(prof_tdata_t) from 200 to 192 which is a round size class. Afterwards the tdata_t size remain unchanged with the last commit, which effectively inlined the storage of thread names for free.
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.