rb_subbuf_max_data_size(9)

💖 rb_subbuf_max_data_size(9) 💖

okay so bestie, we're in the Kernel API Manual, and this page is literally rb_subbuf_max_data_size(9). the function name ate and left no crumbs, no cap. 💅

🌸 NAME 🌸

rb_subbuf_max_data_size — get the maximum payload size of a single event. that's the whole vibe: max payload size, one event, main character energy. ✨

✨ SYNOPSIS ✨

unsigned int rb_subbuf_max_data_size (struct trace_buffer *buffer );

💅 ARGUMENTS 💅

• buffer — A trace buffer. yes bestie, that's the one and only argument. 🫶

🎀 RETURN 🎀

It returns the maximum data payload size that can be stored in a single event. literally that's the number coming back to you, periodt. ✨

🦋 SEE ALSO 🦋

The kernel file in the mix is ./kernel/trace/ring_buffer.c, and the original also points at this whole friend group of (9) pages:

• ring_buffer_event_length(9), ring_buffer_event_data(9), rb_page_capacity(9), rb_subbuf_capacity(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_start(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)

okay that's the page, bestie 🫶 the footer energy is source ./kernel/trace, date October 2026, and the title tag still says rb_subbuf_max_data_size(9). mwah 💋✨