Re: [PATCH v2 09/15] lib min_heap: Add min_heap_sift_up()

Ian Rogers
2024-03-20T17:15:20Z

On Wed, Mar 20, 2024 at 7:55 AM Kuan-Wei Chiu <visitorckw@gmail.com> wrote:
>
> Add min_heap_sift_up() to sift up the element at index 'idx' in the
> heap.

Thanks, should min_heap_push be updated to use this sift up rather
than its inline version?

Ian

> Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
> ---
> include/linux/min_heap.h | 20 ++++++++++++++++++++
> 1 file changed, 20 insertions(+)
>
> diff --git a/include/linux/min_heap.h b/include/linux/min_heap.h
> index 36023e0be232..af12531474a4 100644
> --- a/include/linux/min_heap.h
> +++ b/include/linux/min_heap.h
> @@ -194,6 +194,26 @@ void __min_heap_push(struct __min_heap *heap, const void *element, size_t elem_s
> #define min_heap_push(_heap, _element, _func) \
> __min_heap_push(&(_heap)->heap, _element, __minheap_obj_size(_heap), _func)
>
> +/* Sift up ith element from the heap, O(log2(nr)). */
> +static __always_inline
> +void __min_heap_sift_up(struct __min_heap *heap, size_t elem_size, size_t idx,
> + const struct min_heap_callbacks *func, void *args)
> +{
> + void *data = heap->data;
> + size_t parent;
> +
> + while (idx) {
> + parent = (idx - 1) / 2;
> + if (func->less(data + parent * elem_size, data + idx * elem_size, args))
> + break;
> + func->swp(data + parent * elem_size, data + idx * elem_size, args);
> + idx = parent;
> + }
> +}
> +
> +#define min_heap_sift_up(_heap, _idx, _func, _args) \
> + __min_heap_sift_up(&(_heap)->heap, __minheap_obj_size(_heap), _idx, _func, _args)
> +
> /* Remove ith element from the heap, O(log2(nr)). */
> static __always_inline
> bool __min_heap_del(struct __min_heap *heap, size_t elem_size, size_t idx,
> --
> 2.34.1
>