Commit db7b3377 authored by David Hildenbrand's avatar David Hildenbrand Committed by Michael S. Tsirkin
Browse files

virtio-mem: prioritize unplug from ZONE_MOVABLE in Big Block Mode 



Let's handle unplug in Big Block Mode similar to Sub Block Mode --
prioritize memory blocks onlined to ZONE_MOVABLE.

We won't care further about big blocks with mixed zones, as it's
rather a corner case that won't matter in practice.

Signed-off-by: default avatarDavid Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20210602185720.31821-8-david@redhat.com


Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent c6bc1422

drivers/virtio/virtio_mem.c

+26 −1
Original line number Diff line number Diff line
@@ -2121,6 +2121,29 @@ static bool virtio_mem_bbm_bb_is_offline(struct virtio_mem *vm, 
	return true;

}



/*

 * Test if a big block is completely onlined to ZONE_MOVABLE (or offline).

 */

static bool virtio_mem_bbm_bb_is_movable(struct virtio_mem *vm,

					 unsigned long bb_id)

{

	const unsigned long start_pfn = PFN_DOWN(virtio_mem_bb_id_to_phys(vm, bb_id));

	const unsigned long nr_pages = PFN_DOWN(vm->bbm.bb_size);

	struct page *page;

	unsigned long pfn;



	for (pfn = start_pfn; pfn < start_pfn + nr_pages;

	     pfn += PAGES_PER_SECTION) {

		page = pfn_to_online_page(pfn);

		if (!page)

			continue;

		if (page_zonenum(page) != ZONE_MOVABLE)

			return false;

	}



	return true;

}



static int virtio_mem_bbm_unplug_request(struct virtio_mem *vm, uint64_t diff)

{

	uint64_t nb_bb = diff / vm->bbm.bb_size;
@@ -2134,7 +2157,7 @@ static int virtio_mem_bbm_unplug_request(struct virtio_mem *vm, uint64_t diff) 
	 * Try to unplug big blocks. Similar to SBM, start with offline

	 * big blocks.

	 */

	for (i = 0; i < 2; i++) {

	for (i = 0; i < 3; i++) {

		virtio_mem_bbm_for_each_bb_rev(vm, bb_id, VIRTIO_MEM_BBM_BB_ADDED) {

			cond_resched();
@@ -2144,6 +2167,8 @@ static int virtio_mem_bbm_unplug_request(struct virtio_mem *vm, uint64_t diff) 
			 */

			if (i == 0 && !virtio_mem_bbm_bb_is_offline(vm, bb_id))

				continue;

			if (i == 1 && !virtio_mem_bbm_bb_is_movable(vm, bb_id))

				continue;

			rc = virtio_mem_bbm_offline_remove_and_unplug_bb(vm, bb_id);

			if (rc == -EBUSY)

				continue;