On Wed, Jun 05, 2024 at 04:37:38PM -0400, mgalaxy@xxxxxxxxxx wrote:
From: Michael Galaxy <mgalaxy@xxxxxxxxxx>
Update the documentation and changelog accordingly to reflect
that the syntax of the memory_backing_dir setting has changed.
Signed-off-by: Michael Galaxy <mgalaxy@xxxxxxxxxx>
---
NEWS.rst | 7 +++++++
docs/kbase/virtiofs.rst | 2 ++
src/qemu/qemu.conf.in | 2 ++
3 files changed, 11 insertions(+)
diff --git a/NEWS.rst b/NEWS.rst
index f3ca29443a..64be9a9509 100644
--- a/NEWS.rst
+++ b/NEWS.rst
@@ -54,6 +54,13 @@ v10.4.0 (2024-06-03)
ebtables/iptables).
* **Improvements**
+ * qemu: memory backing directories now support NUMA
+
+ The primary use case of this is when persistent memory is used on
+ NUMA-aware systems. The setting ``memory_backing_dir`` in qemu.conf
+ now supports either an array or the original string. This allows
+ you to provide a array of locations to use that are NUMA-compatible
+ if needed.
* qemu: add zstd to supported compression formats
NEWS updates should be in a separate, last commit.
diff --git a/docs/kbase/virtiofs.rst b/docs/kbase/virtiofs.rst
index 457c15da7f..931ba96104 100644
--- a/docs/kbase/virtiofs.rst
+++ b/docs/kbase/virtiofs.rst
@@ -144,6 +144,8 @@ memobject interface).
# This directory is used for memoryBacking source if configured as file.
# NOTE: big files will be stored here
+ # NOTE: In the case of a NUMA-aware system (such has shm/tmpfs or PMEM),
+ # one can also do: memory_backing_dir = [ "/path/to/node/0", "/path/to/node/1" ]
memory_backing_dir = "/dev/shm/"
* Use hugepage-backed memory
diff --git a/src/qemu/qemu.conf.in b/src/qemu/qemu.conf.in
index 6bc2140dcb..e6d1f8a675 100644
--- a/src/qemu/qemu.conf.in
+++ b/src/qemu/qemu.conf.in
@@ -897,6 +897,8 @@
# This directory is used for memoryBacking source if configured as file.
# NOTE: big files will be stored here
+# NOTE: In the case of a NUMA-aware system (such has shm/tmpfs or PMEM),
+# one can also do: memory_backing_dir = [ "/path/to/node/0", "/path/to/node/1" ]
mentioning that the number of directories must be at least as long as the maximum number of nodes of a guest in such case would be nice. Anyway, this needs to go to the same patch that adds such functionality/parsing.
#memory_backing_dir = "/var/lib/libvirt/qemu/ram" # Path to the SCSI persistent reservations helper. This helper is -- 2.34.1
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