From: Michael Galaxy <mgalaxy@akamai.com>

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@akamai.com>
---
 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
 
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" ]
 #memory_backing_dir = "/var/lib/libvirt/qemu/ram"
 
 # Path to the SCSI persistent reservations helper. This helper is
-- 
2.34.1

On Wed, Jun 05, 2024 at 04:37:38PM -0400, mgalaxy@akamai.com wrote:
>From: Michael Galaxy <mgalaxy@akamai.com>
>
>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@akamai.com>
>---
> 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
>

Hi,

Acknowledged all. Thanks again for the instructions/review.

- Michael

On 8/6/24 07:44, Martin Kletzander wrote:
> On Wed, Jun 05, 2024 at 04:37:38PM -0400, mgalaxy@akamai.com wrote:
>> From: Michael Galaxy <mgalaxy@akamai.com>
>>
>> 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@akamai.com>