- Update to version 4.1.0
New features:
* Implement decay-based unused dirty page purging, a major optimization
with mallctl API impact. This is an alternative to the existing ratio-based
unused dirty page purging, and is intended to eventually become the sole
purging mechanism. New mallctls:
+ opt.purge
+ opt.decay_time
+ arena..decay
+ arena..decay_time
+ arenas.decay_time
+ stats.arenas..decay_time
* Add --with-malloc-conf, which makes it possible to embed a default options
string during configuration. This was motivated by the desire to specify
--with-malloc-conf=purge:decay , since the default must remain purge:ratio
until the 5.0.0 release.
* Make *allocx() size class overflow behavior defined. The maximum size
class is now less thanPTRDIFF_MAX to protect applications against numerical
overflow, and all allocation functions are guaranteed to indicate errors
rather than potentially crashing if the request size exceeds the maximum size class.
* jeprof:
+ Add raw heap profile support.
+ Add --retain and --exclude for backtrace symbol filtering.
Optimizations:
* Optimize the fast path to combine various bootstrapping and configuration
checks and execute more streamlined code in the common case.
* Use linear scan for small bitmaps (used for small object tracking).
In addition to speeding up bitmap operations on 64-bit systems, this reduces
allocator metadata overhead by approximately 0.2%.
* Separate arena_avail trees, which substantially speeds up run tree operations.