OPPO Kernel Craftsman
Jan 5, 2024 · Fundamentals
Read‑Write Semaphore (rw_semaphore) and Per‑CPU rwsem in the Linux Kernel (ARM64)
The article explains Linux kernel read‑write semaphores, detailing the classic rw_semaphore’s optimistic‑spinning and hand‑off mechanisms, then introduces the per‑CPU rwsem for ARM64, which replaces global counters with per‑CPU data and an RCU fast‑path to cut cache‑coherency traffic at the cost of losing optimistic spinning.
ARM64Linux kerneloptimistic spinning
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