synchronize_rcu_mult(9)

💖 synchronize_rcu_mult(9) — Kernel API Manual 💖

Ok bestie, welcome to the Kernel API Manual entry for synchronize_rcu_mult(9) — it’s giving “wait for multiple grace periods at once” and honestly? Iconic. ✨

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🌸 NAME 🌸

synchronize_rcu_mult — Wait concurrently for multiple grace periods.

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🦋 SYNOPSIS 🦋

synchronize_rcu_mult (... );

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🎀 ARGUMENTS 🎀

• ... — List of call_rcu functions for different grace periods to wait on. That’s the whole vibe, fr fr.

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💅 DESCRIPTION 💅

This macro waits concurrently for multiple types of RCU grace periods. Like, not one at a time — concurrently, bestie. 🫶

For example, synchronize_rcu_mult(call_rcu, call_rcu_tasks) would wait on concurrent RCU and RCU-tasks grace periods. Slay. 🔥

Waiting on a given SRCU domain requires you to write a wrapper function for that SRCU domain’s call_srcu function, with this wrapper supplying the pointer to the corresponding srcu_struct. So yes, you gotta bring your own little wrapper — it’s not gonna manifest the pointer out of thin air, no cap. 💀

Lowkey important note: call_rcu_hurry should be used instead of call_rcu because in kernels built with CONFIG_RCU_LAZY=y the delay between the invocation of call_rcu and that of the corresponding RCU callback can be multiple seconds. Multiple. Seconds. 😭 So use the hurry one, bestie.

The first argument tells Tiny RCU’s _wait_rcu_gp not to bother waiting for RCU. The reason for this is because anywhere synchronize_rcu_mult can be called is automatically already a full grace period. The way that works out is genuinely a little iconic. 👑

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🌈 SEE ALSO 🌈

• Kernel file ./include/linux/rcupdate_wait.h — go peek, iykyk. 🦋

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Sign-off time, bestie: this page’s source/version footer lives under ./include/linux, dated October 2026. Periodt. 💅🎀🫶