Re: [PATCH 4/5] x86/mm: Provide helpers for unaccepted memory

Dave Hansen
2021-08-10T18:18:18Z

On 8/9/21 11:26 PM, Kirill A. Shutemov wrote:
> +void accept_memory(phys_addr_t start, phys_addr_t end)
> +{
> + if (!boot_params.unaccepted_memory)
> + return;
> +
> + spin_lock(&unaccepted_memory_lock);
> + __accept_memory(start, end);
> + spin_unlock(&unaccepted_memory_lock);
> +}

Isn't this taken in the:

del_page_from_free_list()->
clear_page_offline()->
accept_memory()

call path?

That's underneath:

spin_lock_irqsave(&zone->lock, flags);

Which means that accept_memory() can happen from interrupt context. Is
it always covered by another spin_lock_irqsave() which means that it can
use a plain spin_lock()?

If so, it would be nice to call out that logic. It *looks* like a
spinlock that we would want to be spin_lock_irqsave().