update_counter(9)

💅 update_counter(9) — Kernel API Manual 💅

okay bestie, welcome to the Kernel API Manual page for update_counter(9). it’s short, it’s specific, and it’s all about bumping the counter tied to a given state. let’s go ✨

🌸 NAME 🌸

update_counter — update the counter associated with a given state. that’s the whole vibe: one state, one counter, one update. 💖

✨ SYNOPSIS ✨

void update_counter (struct page_info *info , s32 delta );

🎀 ARGUMENTS 🎀

• info — the page info to count. this is the thing getting counted, bestie 🫶
• delta — the delta to apply to the counter. yes, it’s literally the amount you’re applying, no cap.

🦋 SEE ALSO 🦋

okay so the cross-reference squad is long and iconic, and every single one is here:

• Kernel file ./drivers/md/dm-vdo/block-map.c — Block map eras(9) 🧚
• initialize_info(9)
• allocate_cache_components(9)
• assert_on_cache_thread(9)
• get_page_state_name(9)
• set_info_state(9)
• find_free_page(9)
• find_page(9)
• select_lru_page(9)
• complete_with_page(9)
• complete_waiter_with_error(9)
• complete_waiter_with_page(9)
• distribute_page_over_waitq(9)
• set_persistent_error(9)
• validate_completed_page(9)
• handle_load_error(9)
• page_is_loaded(9)
• handle_rebuild_read_error(9)
• launch_page_load(9)
• schedule_page_save(9)
• launch_page_save(9)
• completion_needs_page(9)
• allocate_free_page(9)
• discard_a_page(9)
• discard_page_if_needed(9)
• write_has_finished(9)
• handle_page_write_error(9)
• page_is_written_out(9)
• write_pages(9)
• vdo_release_page_completion(9)
• vdo_get_page(9)
• vdo_request_page_write(9)
• vdo_get_cached_page(9)
• vdo_invalidate_page_cache(9)
• get_tree_page_by_index(9)
• in_cyclic_range(9)
• is_not_older(9)
• add_to_dirty_lists(9)
• vdo_find_block_map_slot(9)
• make_forest(9)
• replace_forest(9)
• finish_cursor(9)
• continue_traversal(9)
• finish_traversal_load(9)
• traverse(9)
• launch_cursor(9)
• compute_boundary(9)
• vdo_traverse_forest(9)
• initialize_block_map_zone(9)
• clear_mapped_location(9)
• set_mapped_location(9)

mwah 💋 — that’s the whole page, sourced from ./drivers/md/dm-vdo, dated October 2026, and it’s the update_counter(9) moment. periodt 🎀