[v3,06/28] vhost: don't dump unneeded pages with IOTLB

Message ID 20230525162551.70359-7-maxime.coquelin@redhat.com (mailing list archive)
State Superseded, archived
Delegated to: Maxime Coquelin
Headers
Series Add VDUSE support to Vhost library |

Checks

Context Check Description
ci/checkpatch success coding style OK

Commit Message

Maxime Coquelin May 25, 2023, 4:25 p.m. UTC
  On IOTLB entry removal, previous fixes took care of not
marking pages shared with other IOTLB entries as DONTDUMP.

However, if an IOTLB entry is spanned on multiple pages,
the other pages were kept as DODUMP while they might not
have been shared with other entries, increasing needlessly
the coredump size.

This patch addresses this issue by excluding only the
shared pages from madvise's DONTDUMP.

Fixes: dea092d0addb ("vhost: fix madvise arguments alignment")
Cc: stable@dpdk.org

Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Acked-by: Mike Pattrick <mkp@redhat.com>
Reviewed-by: Chenbo Xia <chenbo.xia@intel.com>
---
 lib/vhost/iotlb.c | 21 ++++++++++++++-------
 1 file changed, 14 insertions(+), 7 deletions(-)
  

Patch

diff --git a/lib/vhost/iotlb.c b/lib/vhost/iotlb.c
index 59a2b2bbac..5c5200114e 100644
--- a/lib/vhost/iotlb.c
+++ b/lib/vhost/iotlb.c
@@ -54,16 +54,23 @@  static void
 vhost_user_iotlb_clear_dump(struct virtio_net *dev, struct vhost_iotlb_entry *node,
 		struct vhost_iotlb_entry *prev, struct vhost_iotlb_entry *next)
 {
-	uint64_t align;
+	uint64_t align, start, end;
+
+	start = node->uaddr;
+	end = node->uaddr + node->size;
 
 	align = hua_to_alignment(dev->mem, (void *)(uintptr_t)node->uaddr);
 
-	/* Don't disable coredump if the previous node is in the same page */
-	if (!vhost_user_iotlb_share_page(prev, node, align)) {
-		/* Don't disable coredump if the next node is in the same page */
-		if (!vhost_user_iotlb_share_page(node, next, align))
-			mem_set_dump((void *)(uintptr_t)node->uaddr, node->size, false, align);
-	}
+	/* Skip first page if shared with previous entry. */
+	if (vhost_user_iotlb_share_page(prev, node, align))
+		start = RTE_ALIGN_CEIL(start, align);
+
+	/* Skip last page if shared with next entry. */
+	if (vhost_user_iotlb_share_page(node, next, align))
+		end = RTE_ALIGN_FLOOR(end, align);
+
+	if (end > start)
+		mem_set_dump((void *)(uintptr_t)start, end - start, false, align);
 }
 
 static struct vhost_iotlb_entry *