On 19.10.22 13:53, Konstantin Khlebnikov wrote:
On Wed, 19 Oct 2022 at 12:57, Alexander Atanasov
<alexander.atanasov@xxxxxxxxxxxxx
<mailto:alexander.atanasov@xxxxxxxxxxxxx>> wrote:
Currently balloon drivers (Virtio,XEN, HyperV, VMWare, ...)
inflate and deflate the guest memory size but there is no
way to know how much the memory size is changed by them.
Make it possible for the drivers to report the values to mm core.
Display reported InflatedTotal and InflatedFree in /proc/meminfo
and print these values on OOM and sysrq from show_mem().
The two values are the result of the two modes the drivers work
with using adjust_managed_page_count or without.
In earlier versions, there was a notifier for these changes
but after discussion - it is better to implement it in separate
patch series. Since it came out as larger work than initially expected.
Amount of inflated memory can be used:
- totalram_pages() users working with drivers not using
adjust_managed_page_count
- si_meminfo(..) users can improve calculations
- by userspace software that monitors memory pressure
Sorry, I see no reason for that series.
Balloon inflation adjusts totalram_pages. That's enough.
That is not true in all cases - some do some do not.
There is no reason to know the amount of non-existent ballooned memory
inside.
Why? Memory managment is becoming more and more dynamic - to make it
easy and accurate you need to know that amount. The kernel itself
on boot pre-allocates caches and sets limits based on total ram at boot
time when balloon steals half of the memory these initial calculations
become very wrong. To redo them correctly these amounts need to be
known. The idea of doing this is thru a notifier chain in a separte series.
Management software which works outside should care about that.
For debugging you could get current balloon size from /proc/vmstat
(balloon_inflate - balloon_deflate).
Currently you can do that only if using VMWare balloon.
Also (I guess) /proc/kpageflags has a bit for that.
Anyway it's easy to monitor balloon inflation by seeing changes of total
memory size.
Not all drivers do that - VMWare and virtio (in one case) for example do
not. I proposed to unify them but since it can break existing users it
was NAKed.
Alexander Atanasov (8):
mm: Make a place for a common balloon code
mm: Enable balloon drivers to report inflated memory
mm: Display inflated memory to users
mm: Display inflated memory in logs
drivers: virtio: balloon - report inflated memory
drivers: vmware: balloon - report inflated memory
drivers: hyperv: balloon - report inflated memory
documentation: create a document about how balloon drivers operate
Documentation/filesystems/proc.rst | 6 +
Documentation/mm/balloon.rst | 138 ++++++++++++++++++
MAINTAINERS | 4 +-
arch/powerpc/platforms/pseries/cmm.c | 2 +-
drivers/hv/hv_balloon.c | 12 ++
drivers/misc/vmw_balloon.c | 3 +-
drivers/virtio/virtio_balloon.c | 7 +-
fs/proc/meminfo.c | 10 ++
.../linux/{balloon_compaction.h => balloon.h} | 18 ++-
lib/show_mem.c | 8 +
mm/Makefile | 2 +-
mm/{balloon_compaction.c => balloon.c} | 19 ++-
mm/migrate.c | 1 -
mm/vmscan.c | 1 -
14 files changed, 213 insertions(+), 18 deletions(-)
create mode 100644 Documentation/mm/balloon.rst
rename include/linux/{balloon_compaction.h => balloon.h} (91%)
rename mm/{balloon_compaction.c => balloon.c} (94%)
v4->v5:
- removed notifier
- added documentation
- vmware update after op is done , outside of the mutex
v3->v4:
- add support in hyperV and vmware balloon drivers
- display balloon memory in show_mem so it is logged on OOM and on
sysrq
v2->v3:
- added missed EXPORT_SYMBOLS
Reported-by: kernel test robot <lkp@xxxxxxxxx <mailto:lkp@xxxxxxxxx>>
- instead of balloon_common.h just use balloon.h (yes, naming is hard)
- cleaned up balloon.h - remove from files that do not use it and
remove externs from function declarations
v1->v2:
- reworked from simple /proc/meminfo addition
Cc: Michael S. Tsirkin <mst@xxxxxxxxxx <mailto:mst@xxxxxxxxxx>>
Cc: David Hildenbrand <david@xxxxxxxxxx <mailto:david@xxxxxxxxxx>>
Cc: Wei Liu <wei.liu@xxxxxxxxxx <mailto:wei.liu@xxxxxxxxxx>>
Cc: Nadav Amit <namit@xxxxxxxxxx <mailto:namit@xxxxxxxxxx>>
Cc: pv-drivers@xxxxxxxxxx <mailto:pv-drivers@xxxxxxxxxx>
Cc: Jason Wang <jasowang@xxxxxxxxxx <mailto:jasowang@xxxxxxxxxx>>
Cc: virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx
<mailto:virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx>
Cc: "K. Y. Srinivasan" <kys@xxxxxxxxxxxxx <mailto:kys@xxxxxxxxxxxxx>>
Cc: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx
<mailto:haiyangz@xxxxxxxxxxxxx>>
Cc: Stephen Hemminger <sthemmin@xxxxxxxxxxxxx
<mailto:sthemmin@xxxxxxxxxxxxx>>
Cc: Dexuan Cui <decui@xxxxxxxxxxxxx <mailto:decui@xxxxxxxxxxxxx>>
Cc: linux-hyperv@xxxxxxxxxxxxxxx <mailto:linux-hyperv@xxxxxxxxxxxxxxx>
Cc: Juergen Gross <jgross@xxxxxxxx <mailto:jgross@xxxxxxxx>>
Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx
<mailto:sstabellini@xxxxxxxxxx>>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx
<mailto:oleksandr_tyshchenko@xxxxxxxx>>
Cc: xen-devel@xxxxxxxxxxxxxxxxxxxx
<mailto:xen-devel@xxxxxxxxxxxxxxxxxxxx>
base-commit: 9abf2313adc1ca1b6180c508c25f22f9395cc780
--
2.31.1
--
Regards,
Alexander Atanasov
