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[PATCH v1 15/15] virtio-mem: Mark memslot alias memory regions unmergeab
From: |
David Hildenbrand |
Subject: |
[PATCH v1 15/15] virtio-mem: Mark memslot alias memory regions unmergeable |
Date: |
Fri, 16 Jun 2023 11:26:54 +0200 |
Let's mark the memslot alias memory regions as unmergable, such that
flatview and vhost won't merge adjacent memory region aliases and we can
atomically map/unmap individual aliases without affecting adjacent
alias memory regions.
This fixes issues with vhost and vfio (which do not support atomic memslot
updates) and avoids the temporary removal of large memslots, which
can be an expensive operation. For example, vfio might have to unpin +
repin a lot of memory, which is undesired.
Signed-off-by: David Hildenbrand <david@redhat.com>
---
hw/virtio/virtio-mem.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/hw/virtio/virtio-mem.c b/hw/virtio/virtio-mem.c
index 516370067a..cccd834466 100644
--- a/hw/virtio/virtio-mem.c
+++ b/hw/virtio/virtio-mem.c
@@ -955,6 +955,12 @@ static void virtio_mem_prepare_memslots(VirtIOMEM *vmem)
memory_region_init_alias(&vmem->memslots[idx], OBJECT(vmem), name,
&vmem->memdev->mr, memslot_offset,
memslot_size);
+ /*
+ * We want to be able to atomically and efficiently activate/deactivate
+ * individual memslots without affecting adjacent memslots in memory
+ * notifiers.
+ */
+ memory_region_set_unmergeable(&vmem->memslots[idx], true);
}
}
--
2.40.1
- [PATCH v1 04/15] memory-device, vhost: Add a memslot soft limit for memory devices, (continued)
- [PATCH v1 04/15] memory-device, vhost: Add a memslot soft limit for memory devices, David Hildenbrand, 2023/06/16
- [PATCH v1 05/15] kvm: Return number of free memslots, David Hildenbrand, 2023/06/16
- [PATCH v1 06/15] vhost: Return number of free memslots, David Hildenbrand, 2023/06/16
- [PATCH v1 07/15] memory-device: Support memory devices that statically consume multiple memslots, David Hildenbrand, 2023/06/16
- [PATCH v1 08/15] memory-device: Track the actually used memslots in DeviceMemoryState, David Hildenbrand, 2023/06/16
- [PATCH v1 09/15] memory-device, vhost: Support memory devices that dynamically consume multiple memslots, David Hildenbrand, 2023/06/16
- [PATCH v1 10/15] pc-dimm: Provide pc_dimm_get_free_slots() to query free ram slots, David Hildenbrand, 2023/06/16
- [PATCH v1 11/15] memory-device: Support memory-devices with auto-detection of the number of memslots, David Hildenbrand, 2023/06/16
- [PATCH v1 12/15] memory: Clarify mapping requirements for RamDiscardManager, David Hildenbrand, 2023/06/16
- [PATCH v1 13/15] virtio-mem: Expose device memory via multiple memslots if enabled, David Hildenbrand, 2023/06/16
- [PATCH v1 15/15] virtio-mem: Mark memslot alias memory regions unmergeable,
David Hildenbrand <=
- [PATCH v1 14/15] memory, vhost: Allow for marking memory device memory regions unmergeable, David Hildenbrand, 2023/06/16