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From:   Zi Yan <zi.yan@sent.com>
To:     David Hildenbrand <david@redhat.com>, linux-mm@kvack.org
Cc:     Matthew Wilcox <willy@infradead.org>,
        Vlastimil Babka <vbabka@suse.cz>,
        "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
        Mike Kravetz <mike.kravetz@oracle.com>,
        Michal Hocko <mhocko@kernel.org>,
        John Hubbard <jhubbard@nvidia.com>,
        linux-kernel@vger.kernel.org, Zi Yan <ziy@nvidia.com>,
        "Michael S. Tsirkin" <mst@redhat.com>,
        Jason Wang <jasowang@redhat.com>,
        virtualization@lists.linux-foundation.org
Subject: [RFC PATCH 09/15] virtio: virtio_mem: use PAGES_PER_SECTION instead of MAX_ORDER_NR_PAGES
Date:   Thu,  5 Aug 2021 15:02:47 -0400
Message-Id: <20210805190253.2795604-10-zi.yan@sent.com>
In-Reply-To: <20210805190253.2795604-1-zi.yan@sent.com>
References: <20210805190253.2795604-1-zi.yan@sent.com>
Reply-To: Zi Yan <ziy@nvidia.com>
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From: Zi Yan <ziy@nvidia.com>

It keeps the existing behavior when MAX_ORDER grows beyond a section
size.

Signed-off-by: Zi Yan <ziy@nvidia.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: virtualization@lists.linux-foundation.org
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
---
 drivers/virtio/virtio_mem.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c
index 19036922f7ef..bab5a81fa796 100644
--- a/drivers/virtio/virtio_mem.c
+++ b/drivers/virtio/virtio_mem.c
@@ -1105,11 +1105,11 @@ static void virtio_mem_clear_fake_offline(unsigned =
long pfn,
  */
 static void virtio_mem_fake_online(unsigned long pfn, unsigned long nr_pag=
es)
 {
-	const unsigned long max_nr_pages =3D MAX_ORDER_NR_PAGES;
+	const unsigned long max_nr_pages =3D PAGES_PER_SECTION;
 	unsigned long i;
=20
 	/*
-	 * We are always called at least with MAX_ORDER_NR_PAGES
+	 * We are always called at least with PAGES_PER_SECTION
 	 * granularity/alignment (e.g., the way subblocks work). All pages
 	 * inside such a block are alike.
 	 */
@@ -1125,7 +1125,7 @@ static void virtio_mem_fake_online(unsigned long pfn,=
 unsigned long nr_pages)
 		if (PageDirty(page)) {
 			virtio_mem_clear_fake_offline(pfn + i, max_nr_pages,
 						      false);
-			generic_online_page(page, MAX_ORDER - 1);
+			generic_online_page(page, PAGES_PER_SECTION - 1);
 		} else {
 			virtio_mem_clear_fake_offline(pfn + i, max_nr_pages,
 						      true);
@@ -1228,7 +1228,7 @@ static void virtio_mem_online_page_cb(struct page *pa=
ge, unsigned int order)
 		if (vm->in_sbm) {
 			/*
 			 * We exploit here that subblocks have at least
-			 * MAX_ORDER_NR_PAGES size/alignment - so we cannot
+			 * PAGES_PER_SECTION size/alignment - so we cannot
 			 * cross subblocks within one call.
 			 */
 			id =3D virtio_mem_phys_to_mb_id(addr);
@@ -2438,14 +2438,14 @@ static int virtio_mem_init(struct virtio_mem *vm)
 				      VIRTIO_MEM_DEFAULT_OFFLINE_THRESHOLD);
=20
 	/*
-	 * We want subblocks to span at least MAX_ORDER_NR_PAGES and
+	 * We want subblocks to span at least PAGES_PER_SECTION 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.
 	 */
-	sb_size =3D max_t(uint64_t, MAX_ORDER_NR_PAGES,
+	sb_size =3D max_t(uint64_t, PAGES_PER_SECTION,
 			pageblock_nr_pages) * PAGE_SIZE;
 	sb_size =3D max_t(uint64_t, vm->device_block_size, sb_size);
=20
--=20
2.30.2