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feat(kernel): batch RCU callbacks with RCU_LAZY - #655
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ouroboros420 wants to merge 1 commit into
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ouroboros420 wants to merge 1 commit into
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Without it every call_rcu() soon starts a grace period, waking idle CPUs for kernel housekeeping. RCU_LAZY offloads callbacks to rcuo kthreads and batches them for up to 10 s, flushing early under memory pressure or when many queue up. Android's GKI builds the same options in (lazy off by default) and ChromeOS runs it on. rcutree.enable_rcu_lazy=0 turns it off at boot. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
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Enables RCU_NOCB_CPU on all CPUs and RCU_LAZY, so call_rcu() callbacks are batched for up to 10 s instead of waking idle CPUs. Android's GKI builds the same options in (lazy off by default) and ChromeOS runs it on. rcutree.enable_rcu_lazy=0 turns it off at boot.
Needs testing.