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From: Ian Rogers <irogers@google.com>
Date: Sun, 7 Apr 2024 12:10:42 -0700
Message-ID: <CAP-5=fWb3eNe3mufRJjPAc=jcHFiHYpPqLuK2H8YiijHu0rLZw@mail.gmail.com>
Subject: Re: [PATCH v3 09/17] lib min_heap: Add min_heap_sift_up()
To: Kuan-Wei Chiu <visitorckw@gmail.com>
Cc: colyli@suse.de, kent.overstreet@linux.dev, msakai@redhat.com, 
	peterz@infradead.org, mingo@redhat.com, acme@kernel.org, namhyung@kernel.org, 
	akpm@linux-foundation.org, bfoster@redhat.com, mark.rutland@arm.com, 
	alexander.shishkin@linux.intel.com, jolsa@kernel.org, adrian.hunter@intel.com, 
	jserv@ccns.ncku.edu.tw, linux-bcache@vger.kernel.org, 
	linux-kernel@vger.kernel.org, dm-devel@lists.linux.dev, 
	linux-bcachefs@vger.kernel.org, linux-perf-users@vger.kernel.org
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On Sat, Apr 6, 2024 at 9:48=E2=80=AFAM Kuan-Wei Chiu <visitorckw@gmail.com>=
 wrote:
>
> Add min_heap_sift_up() to sift up the element at index 'idx' in the
> heap.
>
> Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>

Reviewed-by: Ian Rogers <irogers@google.com>

Thanks,
Ian

> ---
>  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 9391f7cc9da9..201f59cb3558 100644
> --- a/include/linux/min_heap.h
> +++ b/include/linux/min_heap.h
> @@ -111,6 +111,26 @@ void __min_heapify(min_heap_char *heap, int pos, siz=
e_t elem_size,
>  #define min_heapify(_heap, _pos, _func, _args) \
>         __min_heapify((min_heap_char *)_heap, _pos, __minheap_obj_size(_h=
eap), _func, _args)
>
> +/* Sift up ith element from the heap, O(log2(nr)). */
> +static __always_inline
> +void __min_heap_sift_up(min_heap_char *heap, size_t elem_size, size_t id=
x,
> +               const struct min_heap_callbacks *func, void *args)
> +{
> +       void *data =3D heap->data;
> +       size_t parent;
> +
> +       while (idx) {
> +               parent =3D (idx - 1) / 2;
> +               if (func->less(data + parent * elem_size, data + idx * el=
em_size, args))
> +                       break;
> +               func->swp(data + parent * elem_size, data + idx * elem_si=
ze, args);
> +               idx =3D parent;
> +       }
> +}
> +
> +#define min_heap_sift_up(_heap, _idx, _func, _args)    \
> +       __min_heap_sift_up((min_heap_char *)_heap, __minheap_obj_size(_he=
ap), _idx, _func, _args)
> +
>  /* Floyd's approach to heapification that is O(nr). */
>  static __always_inline
>  void __min_heapify_all(min_heap_char *heap, size_t elem_size,
> --
> 2.34.1
>