ring_buffer_nest_start(9)

🌸 NAME 🌸

bestie, welcome to the ring_buffer_nest_start(9) page from the Kernel API Manual. Short version: ring_buffer_nest_start — allow to trace while nested. That's the whole vibe. 💅

✨ SYNOPSIS ✨

void ring_buffer_nest_start (struct trace_buffer *buffer );

🎀 ARGUMENTS 🎀

• buffer — the ring buffer you're modifying. This is the one getting the little nest-mode glow-up. ✨

💅 DESCRIPTION 💅

okay so real talk: the ring buffer has a safety mechanism to prevent recursion. Very responsible. Very demure. But there may be a case where a trace needs to be done while tracing something else — and that's where this icon comes in. In this case, calling this function lets this function nest within a currently active ring_buffer_lock_reserve. no cap. 🫶

The order matters, bestie: call this function before calling another ring_buffer_lock_reserve, and call ring_buffer_nest_end after the nested ring_buffer_unlock_commit. That's the whole choreography. 🩰

🔥 SEE ALSO 🔥

Kernel file: ./kernel/trace/ring_buffer.c. Here's the whole cross-ref squad — every single one, because we don't do missing links in this house:

• ring_buffer_event_length(9), ring_buffer_event_data(9), rb_page_capacity(9), rb_subbuf_capacity(9), rb_subbuf_max_data_size(9), rb_subbuf_start(9)
• ring_buffer_event_time_stamp(9), ring_buffer_nr_dirty_pages(9), ring_buffer_wake_waiters(9), ring_buffer_wait(9), ring_buffer_poll_wait(9), rb_check_pages(9)
• rb_validate_buffer(9), __ring_buffer_alloc(9), __ring_buffer_alloc_range(9), __ring_buffer_alloc_remote(9), ring_buffer_free(9), ring_buffer_resize(9)
• rb_update_event(9), ring_buffer_nest_end(9), ring_buffer_unlock_commit(9), ring_buffer_lock_reserve(9), ring_buffer_discard_commit(9), ring_buffer_write(9)
• ring_buffer_record_disable(9), ring_buffer_record_enable(9), ring_buffer_record_off(9), ring_buffer_record_on(9), ring_buffer_record_is_on(9), ring_buffer_record_is_set_on(9)
• ring_buffer_record_is_on_cpu(9), ring_buffer_record_disable_cpu(9), ring_buffer_record_enable_cpu(9), ring_buffer_oldest_event_ts(9), ring_buffer_bytes_cpu(9), ring_buffer_entries_cpu(9)
• ring_buffer_overrun_cpu(9), ring_buffer_commit_overrun_cpu(9), ring_buffer_dropped_events_cpu(9), ring_buffer_read_events_cpu(9), ring_buffer_entries(9), ring_buffer_overruns(9)
• ring_buffer_iter_reset(9), ring_buffer_iter_empty(9), ring_buffer_peek(9), ring_buffer_iter_peek(9), ring_buffer_consume(9), ring_buffer_read_start(9)
• ring_buffer_read_finish(9), ring_buffer_iter_advance(9), ring_buffer_size(9), ring_buffer_max_event_size(9), ring_buffer_reset_cpu(9), ring_buffer_reset_online_cpus(9)
• ring_buffer_reset(9), ring_buffer_empty(9), ring_buffer_empty_cpu(9), ring_buffer_swap_cpu(9), ring_buffer_alloc_read_page(9), ring_buffer_free_read_page(9)
• ring_buffer_read_page(9), ring_buffer_read_page_data(9), ring_buffer_read_page_size(9), ring_buffer_subbuf_size_get(9), ring_buffer_subbuf_order_get(9), ring_buffer_subbuf_order_set(9)

mwah 💋 — source/version: ./kernel/trace • date: October 2026 • page: ring_buffer_nest_start(9).