virtio-mem: simplify MAX_ORDER - 1 / pageblock_order handling (20b91502) · Commits · 戴 / test

drivers/virtio/virtio_mem.c

+19 −16

Original line number	Diff line number	Diff line
		@@ -753,14 +753,15 @@ static void virtio_mem_clear_fake_offline(unsigned long pfn,
		*/
		static void virtio_mem_fake_online(unsigned long pfn, unsigned int nr_pages)
		{
		const int order = MAX_ORDER - 1;
		const unsigned long max_nr_pages = MAX_ORDER_NR_PAGES;
		int i;

		/*
		* We are always called with subblock granularity, which is at least
		* aligned to MAX_ORDER - 1.
		* 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.
		*/
		for (i = 0; i < nr_pages; i += 1 << order) {
		for (i = 0; i < nr_pages; i += max_nr_pages) {
		struct page *page = pfn_to_page(pfn + i);

		/*
		@@ -770,14 +771,14 @@ static void virtio_mem_fake_online(unsigned long pfn, unsigned int nr_pages)
		* alike.
		*/
		if (PageDirty(page)) {
		virtio_mem_clear_fake_offline(pfn + i, 1 << order,
		virtio_mem_clear_fake_offline(pfn + i, max_nr_pages,
		false);
		generic_online_page(page, order);
		generic_online_page(page, MAX_ORDER - 1);
		} else {
		virtio_mem_clear_fake_offline(pfn + i, 1 << order,
		virtio_mem_clear_fake_offline(pfn + i, max_nr_pages,
		true);
		free_contig_range(pfn + i, 1 << order);
		adjust_managed_page_count(page, 1 << order);
		free_contig_range(pfn + i, max_nr_pages);
		adjust_managed_page_count(page, max_nr_pages);
		}
		}
		}
		@@ -790,7 +791,7 @@ static void virtio_mem_online_page_cb(struct page *page, unsigned int order)
		int sb_id;

		/*
		* We exploit here that subblocks have at least MAX_ORDER - 1
		* We exploit here that subblocks have at least MAX_ORDER_NR_PAGES.
		* size/alignment and that this callback is is called with such a
		* size/alignment. So we cannot cross subblocks and therefore
		* also not memory blocks.
		@@ -1673,13 +1674,15 @@ static int virtio_mem_init(struct virtio_mem *vm)
		"Some memory is not addressable. This can make some memory unusable.\n");

		/*
		* Calculate the subblock size:
		* - At least MAX_ORDER - 1 / pageblock_order.
		* - At least the device block size.
		* In the worst case, a single subblock per memory block.
		* We want subblocks to span at least MAX_ORDER_NR_PAGES and
		* pageblock_nr_pages pages. This:
		* - Simplifies our page onlining code (virtio_mem_online_page_cb)
		* and 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.
		*/
		vm->subblock_size = PAGE_SIZE * 1ul << max_t(uint32_t, MAX_ORDER - 1,
		pageblock_order);
		vm->subblock_size = max_t(uint64_t, MAX_ORDER_NR_PAGES,
		pageblock_nr_pages) * PAGE_SIZE;
		vm->subblock_size = max_t(uint64_t, vm->device_block_size,
		vm->subblock_size);
		vm->nb_sb_per_mb = memory_block_size_bytes() / vm->subblock_size;

Admin message