rb_page_capacity(9)

okay so bestie 💖 you're on rb_page_capacity(9) from the Kernel API Manual, and this page is literally the “how much room does this buffer page have for events” check. it’s giving tiny-but-important, no cap.

✨ NAME ✨

rb_page_capacity — get the capacity of a buffer page 🎀

🌸 SYNOPSIS 🌸

the signature is exactly:

unsigned int rb_page_capacity (struct buffer_page *bpage );

💅 ARGUMENTS 💅

• bpage — the buffer page. yes bestie, that's the page you're asking about. that's the whole argument, periodt.

🦋 RETURN 🦋

the maximum size available for events in the given buffer page. basically: “how much event room ya got?” 💖

👑 SEE ALSO 👑

the kernel file is ./kernel/trace/ring_buffer.c, and there are so many related functions here — go snoop on all of these, iykyk:

• Kernel file ./kernel/trace/ring_buffer.c
• ring_buffer_event_length(9), ring_buffer_event_data(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_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)

kay bye bestie 🫶 this was rb_page_capacity(9) from the Kernel API Manual, with source/version ./kernel/trace and October 2026 energy. periodt 💅✨