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Re: [Qemu-devel] [PATCH v4 1/4] bitmap: bitmap_count_one_with_offset
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Qemu-devel] [PATCH v4 1/4] bitmap: bitmap_count_one_with_offset |
Date: |
Wed, 14 Mar 2018 16:20:58 +0000 |
User-agent: |
Mutt/1.9.2 (2017-12-15) |
* Wei Wang (address@hidden) wrote:
> Count the number of 1s in a bitmap starting from an offset.
>
> Signed-off-by: Wei Wang <address@hidden>
> CC: Dr. David Alan Gilbert <address@hidden>
> CC: Juan Quintela <address@hidden>
> CC: Michael S. Tsirkin <address@hidden>
Reviewed-by: Dr. David Alan Gilbert <address@hidden>
> ---
> include/qemu/bitmap.h | 13 +++++++++++++
> 1 file changed, 13 insertions(+)
>
> diff --git a/include/qemu/bitmap.h b/include/qemu/bitmap.h
> index 509eedd..e3f31f1 100644
> --- a/include/qemu/bitmap.h
> +++ b/include/qemu/bitmap.h
> @@ -228,6 +228,19 @@ static inline long bitmap_count_one(const unsigned long
> *bitmap, long nbits)
> }
> }
>
> +static inline long bitmap_count_one_with_offset(const unsigned long *bitmap,
> + long offset, long nbits)
> +{
> + long aligned_offset = QEMU_ALIGN_DOWN(offset, BITS_PER_LONG);
> + long redundant_bits = offset - aligned_offset;
> + long bits_to_count = nbits + redundant_bits;
> + const unsigned long *bitmap_start = bitmap +
> + aligned_offset / BITS_PER_LONG;
> +
> + return bitmap_count_one(bitmap_start, bits_to_count) -
> + bitmap_count_one(bitmap_start, redundant_bits);
> +}
> +
> void bitmap_set(unsigned long *map, long i, long len);
> void bitmap_set_atomic(unsigned long *map, long i, long len);
> void bitmap_clear(unsigned long *map, long start, long nr);
> --
> 1.8.3.1
>
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK
- [Qemu-devel] [PATCH v4 2/4] migration: API to clear bits of guest free pages from the dirty bitmap, (continued)
[Qemu-devel] [PATCH v4 1/4] bitmap: bitmap_count_one_with_offset, Wei Wang, 2018/03/07
- Re: [Qemu-devel] [PATCH v4 1/4] bitmap: bitmap_count_one_with_offset,
Dr. David Alan Gilbert <=
[Qemu-devel] [PATCH v4 4/4] migration: use the free page hint feature from balloon, Wei Wang, 2018/03/07
Re: [Qemu-devel] [PATCH v4 4/4] migration: use the free page hint feature from balloon, Dr. David Alan Gilbert, 2018/03/14
[Qemu-devel] [PATCH v4 3/4] virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_HINT, Wei Wang, 2018/03/07