On Mon 02-03-20 14:49:37, David Hildenbrand wrote:
[...]
> +static void virtio_mem_notify_going_offline(struct virtio_mem *vm,
> + unsigned long mb_id)
> +{
> + const unsigned long nr_pages = PFN_DOWN(vm->subblock_size);
> + unsigned long pfn;
> + int sb_id, i;
> +
> + for (sb_id = 0; sb_id < vm->nb_sb_per_mb; sb_id++) {
> + if (virtio_mem_mb_test_sb_plugged(vm, mb_id, sb_id, 1))
> + continue;
> + /*
> + * Drop our reference to the pages so the memory can get
> + * offlined and add the unplugged pages to the managed
> + * page counters (so offlining code can correctly subtract
> + * them again).
> + */
> + pfn = PFN_DOWN(virtio_mem_mb_id_to_phys(mb_id) +
> + sb_id * vm->subblock_size);
> + adjust_managed_page_count(pfn_to_page(pfn), nr_pages);
> + for (i = 0; i < nr_pages; i++)
> + page_ref_dec(pfn_to_page(pfn + i));
Is there ever situation this might be a different than 1->0 transition?
--
Michal Hocko
SUSE Labs
