Re: [RFCv2 PATCH 5/6] mm/memory_hotplug: Support ACPI hotplug/unplug for coco guest

[Kiryl Shutsemau <kas@kernel.org>]

On Tue, Jun 23, 2026 at 06:17:36AM -0400, Zhenzhong Duan wrote:
> +	spin_lock_irqsave(&unaccepted_memory_lock, flags);
> +	for (; range_start < bitmap_size; range_start = range_end) {
> +		unsigned long phys_start, phys_end;
> +		unsigned long unaccepted_one, plugged_zero;
> +
> +		range_start = find_next_andnot_bit(plugged_bitmap, unaccepted->bitmap,
> +						   bitmap_size, range_start);
> +
> +		if (range_start >= bitmap_size)
> +			break;
> +
> +		unaccepted_one = find_next_bit(unaccepted->bitmap, bitmap_size, range_start);
> +		plugged_zero = find_next_zero_bit(plugged_bitmap, bitmap_size, range_start);
> +		range_end = min(unaccepted_one, plugged_zero);
> +
> +		phys_start = range_start * unit_size + unaccepted->phys_base;
> +		phys_end = range_end * unit_size + unaccepted->phys_base;
> +
> +		arch_unaccept_memory(phys_start, phys_end);
> +		bitmap_set(unaccepted->bitmap, range_start, range_end - range_start);
> +	}
> +	spin_unlock_irqrestore(&unaccepted_memory_lock, flags);

Accept TDCALL under the spin lock will kill scalability.

-- 
  Kiryl Shutsemau / Kirill A. Shutemov