On Thu, Apr 25, 2024 at 07:19:25AM +0000, Wei Yang wrote:
> In memblock_remove_range, we would remove consecutive regions after
> isolation.
>
> Instead of removing each region from end to start one by one, we could
> remove those consecutive regions at once.
I don't think this is worth the churn.
> Signed-off-by: Wei Yang <richard.weiyang@xxxxxxxxx>
> ---
> mm/memblock.c | 24 ++++++++++++++++--------
> 1 file changed, 16 insertions(+), 8 deletions(-)
>
> diff --git a/mm/memblock.c b/mm/memblock.c
> index 5a363ef283d0..53e3aa2cd9a2 100644
> --- a/mm/memblock.c
> +++ b/mm/memblock.c
> @@ -343,12 +343,15 @@ static phys_addr_t __init_memblock memblock_find_in_range(phys_addr_t start,
> return ret;
> }
>
> -static void __init_memblock memblock_remove_region(struct memblock_type *type, unsigned long r)
> +static void __init_memblock memblock_remove_regions(struct memblock_type *type,
> + unsigned long r,
> + unsigned int num)
> {
> - type->total_size -= type->regions[r].size;
> - memmove(&type->regions[r], &type->regions[r + 1],
> - (type->cnt - (r + 1)) * sizeof(type->regions[r]));
> - type->cnt--;
> + for (int i = 0; i < num; i++)
> + type->total_size -= type->regions[r + i].size;
> + memmove(&type->regions[r], &type->regions[r + num],
> + (type->cnt - (r + num)) * sizeof(type->regions[r]));
> + type->cnt -= num;
>
> /* Special case for empty arrays */
> if (type->cnt == 0) {
> @@ -360,6 +363,11 @@ static void __init_memblock memblock_remove_region(struct memblock_type *type, u
> }
> }
>
> +static void __init_memblock memblock_remove_region(struct memblock_type *type, unsigned long r)
> +{
> + memblock_remove_regions(type, r, 1);
> +}
> +
> #ifndef CONFIG_ARCH_KEEP_MEMBLOCK
> /**
> * memblock_discard - discard memory and reserved arrays if they were allocated
> @@ -846,14 +854,14 @@ static int __init_memblock memblock_remove_range(struct memblock_type *type,
> phys_addr_t base, phys_addr_t size)
> {
> int start_rgn, end_rgn;
> - int i, ret;
> + int ret;
>
> ret = memblock_isolate_range(type, base, size, &start_rgn, &end_rgn);
> if (ret)
> return ret;
>
> - for (i = end_rgn - 1; i >= start_rgn; i--)
> - memblock_remove_region(type, i);
> + if (end_rgn - start_rgn)
> + memblock_remove_regions(type, start_rgn, end_rgn - start_rgn);
> return 0;
> }
>
> --
> 2.34.1
>
--
Sincerely yours,
Mike.
