GoKawiil
Tech News
A developer-focused article walks through arena allocators as an alternative to standard malloc/free memory management in C. It explains how typical manual allocation leads to problems like forgotten frees, memory leaks, and slow performance from many small allocations, before introducing arena allocators as a solution and detailing their implementation.
GrapheneOS reports that after a week spent building a partial port for the Pixel 11 series, it cannot complete the port because the devices lack working support for ARM hardware memory tagging (MTE) in software, firmware and likely hardware. The project notes the Pixel 8 introduced hardware MTE in October 2023, but neither Android nor the Pixel OS enabled it by default, and Android 16's Advanced Protection Mode only turns it on for a handful of processes. GrapheneOS adds that Pixel 11 still gains some security upgrades, including post-quantum verified boot, AOSP IMS replacing Samsung Shannon, and a Titan M3 chip.
The jemalloc project shipped version 5.4.0, a maintenance-focused update spanning more than 160 commits aimed at reducing technical debt through refactoring, bug fixes, expanded test coverage, and portability fixes. Key additions include an EXTENT_ALLOC_FLAG_PINNED flag letting custom allocation hooks mark non-reclaimable mappings like HugeTLB pages for preferential reuse, plus new mallctl interfaces to report pinned-memory and mutex statistics. The update also replaces the old fixed tcache refill/flush policy with a dynamic system that adapts to observed demand, removing seven legacy tuning controls in the process.
An analysis traces the evolution of memory allocation from stack-based schemes to dynamic linked-list heaps, garbage collection, and jemalloc's 2006 introduction of 'arenas' for NUMA and multi-core memory management. It notes that standard malloc() implementations serialize concurrent allocation requests, causing multithreaded applications to slow down rather than scale as processor counts increase.