Commit 57c5a5b3 authored by David Hildenbrand's avatar David Hildenbrand Committed by Michael S. Tsirkin
Browse files

virtio-mem: prepare fake page onlining code for granularity smaller than MAX_ORDER - 1 



Let's prepare our fake page onlining code for subblock size smaller than
MAX_ORDER - 1: we might get called for ranges not covering properly
aligned MAX_ORDER - 1 pages. We have to detect the order to use
dynamically.

Signed-off-by: default avatarDavid Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20211126134209.17332-3-david@redhat.com


Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: default avatarZi Yan <ziy@nvidia.com>
Reviewed-by: default avatarEric Ren <renzhengeek@gmail.com>
parent 6639032a

drivers/virtio/virtio_mem.c

+13 −13
Original line number Diff line number Diff line
@@ -1121,15 +1121,18 @@ static void virtio_mem_clear_fake_offline(unsigned long pfn, 
 */

static void virtio_mem_fake_online(unsigned long pfn, unsigned long nr_pages)

{

	const unsigned long max_nr_pages = MAX_ORDER_NR_PAGES;

	unsigned long order = MAX_ORDER - 1;

	unsigned long i;



	/*

	 * We are always called at least with MAX_ORDER_NR_PAGES

	 * granularity/alignment (e.g., the way subblocks work). All pages

	 * inside such a block are alike.

	 * We might get called for ranges that don't cover properly aligned

	 * MAX_ORDER - 1 pages; however, we can only online properly aligned

	 * pages with an order of MAX_ORDER - 1 at maximum.

	 */

	for (i = 0; i < nr_pages; i += max_nr_pages) {

	while (!IS_ALIGNED(pfn | nr_pages, 1 << order))

		order--;



	for (i = 0; i < nr_pages; i += 1 << order) {

		struct page *page = pfn_to_page(pfn + i);



		/*
@@ -1139,14 +1142,12 @@ static void virtio_mem_fake_online(unsigned long pfn, unsigned long nr_pages) 
		 * alike.

		 */

		if (PageDirty(page)) {

			virtio_mem_clear_fake_offline(pfn + i, max_nr_pages,

						      false);

			generic_online_page(page, MAX_ORDER - 1);

			virtio_mem_clear_fake_offline(pfn + i, 1 << order, false);

			generic_online_page(page, order);

		} else {

			virtio_mem_clear_fake_offline(pfn + i, max_nr_pages,

						      true);

			free_contig_range(pfn + i, max_nr_pages);

			adjust_managed_page_count(page, max_nr_pages);

			virtio_mem_clear_fake_offline(pfn + i, 1 << order, true);

			free_contig_range(pfn + i, 1 << order);

			adjust_managed_page_count(page, 1 << order);

		}

	}

}
@@ -2477,7 +2478,6 @@ static int virtio_mem_init_hotplug(struct virtio_mem *vm) 
	/*

	 * We want subblocks to span at least MAX_ORDER_NR_PAGES and

	 * pageblock_nr_pages pages. This:

	 * - Simplifies our fake page onlining code (virtio_mem_fake_online).

	 * - Is required for now for alloc_contig_range() to work reliably -

	 *   it doesn't properly handle smaller granularity on ZONE_NORMAL.

	 */