https://jasper-aa64.github.io/tags/tlb-shootdown/Recent content in Tlb-Shootdown on JasperHugoen-usWed, 04 Nov 2026 00:00:00 +0000https://jasper-aa64.github.io/posts/low-latency-context-switch-page-table-tlb/Wed, 04 Nov 2026 00:00:00 +0000https://jasper-aa64.github.io/posts/low-latency-context-switch-page-table-tlb/Threads are lighter than processes because the TLB and caches stay usable after the switch, not because the switch itself is cheaper. The TLB has no MESI: when any thread in a process changes the page tables, every core still holding that page table gets interrupted, and pinning and isolcpus cannot prevent it, so once a hot-path process is running its address space is read-only.https://jasper-aa64.github.io/posts/hot-path-memory-allocators/Thu, 17 Sep 2026 00:00:00 +0000https://jasper-aa64.github.io/posts/hot-path-memory-allocators/Every technique in this post does the same thing at a different layer: move an uncertain, kernel-involving operation off the hot path and force it to happen once, upfront, before it can ambush a single request. An object pool replaces malloc’s variable-cost search with an always-O(1) free list. mlockall and careful mallopt tuning stop the kernel from quietly taking pages back — and pre-faulting closes the one gap mlock alone leaves open. A hand-rolled arena allocator makes the STL itself cooperate with a custom allocator backed by bump-pointer memory. std::pmr solves the same STL-cooperation problem the standard library’s way — trading compile-time speed for runtime flexibility.