[PATCH v1 00/10] move memory module align to PostParse time

[Michal Privoznik]

On 11/11/20 11:07 PM, Daniel Henrique Barboza wrote:
> Hi,
> 
> This is a work that I intended to do after pSeries NVDIMM changes
> I made in commit v6.7.0-302-gd3f3c2c97f. The reasoning is that
> if ppc64 NVDIMM alignment can be done in PostParse time, regular
> ppc64 DIMMs alignment can also be done the same way. After that
> I realized that the same logic can be applied to x86 as well,
> and then I started to see where we could eliminate explicit
> align calls.
> 
> The end result is that a bug that affects pSeries the most
> was found and fixed in patch 02, and now we're able to reflect
> the exact memory being used by the guest in the live XML since
> the alignment is now done in parse time. The series can be
> fetched from:
> 
> https://gitlab.com/danielhb/libvirt/-/tree/memory_modules_postparse_v1
> 
> NOTE: I worked with the x86 logic based on what I could assert
> from the code itself, i.e. the aligment mechanics (2MiB align for
> mem modules, 1MiB align for total memory) are related to QEMU
> internals, not being hypervisor-agnostic. If someone with authority can
> guarantee that the alignment restrictions for x86 are applicable
> to all hypervisors (like in the pSeries case), let me know and
> I'll respin the series putting the x86 code in
> virDomainMemoryDefPostParse().
> 
> 
> Daniel Henrique Barboza (10):
>    domain_conf.c: handle all ppc64 dimms in
>      virDomainNVDimmAlignSizePseries
>    qemu_domain.c: align memory modules before calculating 'initialmem'
>    domain_conf.c: align pSeries mem modules in
>      virDomainMemoryDefPostParse()
>    qemu_domain.c: simplify qemuDomainGetMemoryModuleSizeAlignment()
>    qemu_domain.c: align x86 memory module in post parse time
>    qemu_domain.c: move size check for mem modules after alignment
>    qemu_hotplug.c: avoid aligning the mem obj in
>      qemuDomainDetachPrepMemory()
>    qemu_hotplug.c: avoid aligning the mem obj in qemuDomainAttachMemory()
>    qemu_domain.c: remove qemuDomainMemoryDeviceAlignSize()
>    NEWS.rs: document memory alignment improvements
> 
>   NEWS.rst                                      |  14 +++
>   src/conf/domain_conf.c                        |  25 ++++-
>   src/conf/domain_conf.h                        |   2 +-
>   src/libvirt_private.syms                      |   2 +-
>   src/qemu/qemu_domain.c                        | 106 +++++++-----------
>   src/qemu/qemu_domain.h                        |   2 -
>   src/qemu/qemu_hotplug.c                       |   9 +-
>   tests/qemuxml2argvdata/hugepages-nvdimm.xml   |   2 +-
>   .../memory-hotplug-nvdimm-access.xml          |   2 +-
>   .../memory-hotplug-nvdimm-align.xml           |   2 +-
>   .../memory-hotplug-nvdimm-label.xml           |   2 +-
>   .../memory-hotplug-nvdimm-pmem.xml            |   2 +-
>   .../memory-hotplug-nvdimm-readonly.xml        |   2 +-
>   .../memory-hotplug-nvdimm.xml                 |   2 +-
>   .../memory-hotplug-ppc64-nonuma.args          |   2 +-
>   tests/qemuxml2argvdata/pages-dimm-discard.xml |   2 +-
>   .../memory-hotplug-dimm.xml                   |   4 +-
>   17 files changed, 92 insertions(+), 90 deletions(-)
> 

Reviewed-by: Michal Privoznik <mprivozn at redhat.com>

but perhaps you want Andrea to look into it too.

Michal