Hi Yuntao,
On Tue, Apr 23, 2024 at 09:55:25PM +0800, Yuntao Wang wrote:
> In the logic for hiding the end of the bitmap, there are several places
> where the same value 'region_bits - offset_bits' is calculated over and
> over again using different methods. Eliminate these redundant calculations
> to improve code readability.
>
> Signed-off-by: Yuntao Wang <ytcoode@xxxxxxxxx>
> ---
> mm/percpu.c | 12 +++++-------
> 1 file changed, 5 insertions(+), 7 deletions(-)
>
> diff --git a/mm/percpu.c b/mm/percpu.c
> index 4e11fc1e6def..2a051f00f68d 100644
> --- a/mm/percpu.c
> +++ b/mm/percpu.c
> @@ -1421,15 +1421,13 @@ static struct pcpu_chunk * __init pcpu_alloc_first_chunk(unsigned long tmp_addr,
> if (chunk->end_offset) {
> /* hide the end of the bitmap */
> offset_bits = chunk->end_offset / PCPU_MIN_ALLOC_SIZE;
> - bitmap_set(chunk->alloc_map,
> - pcpu_chunk_map_bits(chunk) - offset_bits,
> - offset_bits);
> - set_bit((start_offset + map_size) / PCPU_MIN_ALLOC_SIZE,
> - chunk->bound_map);
> + start_offset = region_bits - offset_bits;
Generally I think this makes sense, but I'm less inclined to mix the
start_offset variable name in here.
A helper function might make this cleaner, consolidating the
start_offset and end_offset logic.
static void pcpu_chunk_hide_region(chunk, bit_off, bits);
Thanks,
Dennis
> +
> + bitmap_set(chunk->alloc_map, start_offset, offset_bits);
> + set_bit(start_offset, chunk->bound_map);
> set_bit(region_bits, chunk->bound_map);
>
> - pcpu_block_update_hint_alloc(chunk, pcpu_chunk_map_bits(chunk)
> - - offset_bits, offset_bits);
> + pcpu_block_update_hint_alloc(chunk, start_offset, offset_bits);
> }
>
> return chunk;
> --
> 2.44.0
>
