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

Daniel Henrique Barboza danielhb413 at gmail.com
Wed Nov 11 22:07:15 UTC 2020


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(-)

-- 
2.26.2




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