[PATCH v4 0/7] Make balloon drivers memory changes known to the rest of the kernel

[PATCH v4 0/7] Make balloon drivers memory changes known to the rest of the kernel

[Alexander Atanasov]

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.

A common use of the ballooning is to emulate [1]
hot plug and hot unplug - due to the complexity of the later.
Hotplug has a notifier and one can also check the updated
memory size.

To improve this add InflatedTotal and InflatedFree
to /proc/meminfo and implement a balloon notifier.

Amount of inflated memory can be used:
 - si_meminfo(..) users can improve calculations
 - adjust cache/buffer sizes
 - adjust object/connection limits
 - as a hint for the oom a killer
 - by user space software that monitors memory pressure

Alexander Atanasov (7):
  Make place for common balloon code
  Enable balloon drivers to report inflated memory
  Display inflated memory to users
  drivers: virtio: balloon - update inflated memory
  Display inflated memory in logs
  drivers: vmware: balloon - report inflated memory
  drivers: hyperv: balloon - report inflated memory

 Documentation/filesystems/proc.rst            |  6 +++
 MAINTAINERS                                   |  4 +-
 arch/powerpc/platforms/pseries/cmm.c          |  2 +-
 drivers/hv/hv_balloon.c                       | 11 +++++
 drivers/misc/vmw_balloon.c                    |  6 ++-
 drivers/virtio/virtio_balloon.c               |  7 +++-
 fs/proc/meminfo.c                             | 10 +++++
 .../linux/{balloon_compaction.h => balloon.h} | 30 ++++++++++----
 lib/show_mem.c                                |  8 ++++
 mm/Makefile                                   |  2 +-
 mm/{balloon_compaction.c => balloon.c}        | 40 +++++++++++++++++--
 mm/migrate.c                                  |  1 -
 mm/vmscan.c                                   |  1 -
 13 files changed, 110 insertions(+), 18 deletions(-)
 rename include/linux/{balloon_compaction.h => balloon.h} (86%)
 rename mm/{balloon_compaction.c => balloon.c} (88%)

v4:
 - add support in hyperV and vmware balloon drivers
 - display balloon memory in show_mem so it is logged on OOM and on sysrq
v3:
 - added missed EXPORT_SYMBOLS
Reported-by: kernel test robot <lkp@intel.com>
 - 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
v2:
 - reworked from simple /proc/meminfo addition

Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Nadav Amit <namit@vmware.com>
Cc: pv-drivers@vmware.com
Cc: Jason Wang <jasowang@redhat.com>
Cc: virtualization@lists.linux-foundation.org
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: linux-hyperv@vger.kernel.org
Cc: Juergen Gross <jgross@suse.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: xen-devel@lists.xenproject.org

1. https://lore.kernel.org/lkml/f0f12c84-a62e-5f8b-46ab-a651fe8f8589@redhat.com/

base-commit: 2bca25eaeba6190efbfcb38ed169bd7ee43b5aaf
-- 
2.31.1

[PATCH v4 7/7] drivers: hyperv: balloon - report inflated memory

[Alexander Atanasov]

Propagate inflated memory changes to mm.

Signed-off-by: Alexander Atanasov <alexander.atanasov@virtuozzo.com>
---
 drivers/hv/hv_balloon.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c
index fdf6decacf06..b4c828c462a4 100644
--- a/drivers/hv/hv_balloon.c
+++ b/drivers/hv/hv_balloon.c
@@ -24,6 +24,7 @@
 #include <linux/notifier.h>
 #include <linux/percpu_counter.h>
 #include <linux/page_reporting.h>
+#include <linux/balloon.h>
 
 #include <linux/hyperv.h>
 #include <asm/hyperv-tlfs.h>
@@ -1280,6 +1281,13 @@ static unsigned int alloc_balloon_pages(struct hv_dynmem_device *dm,
 	return i * alloc_unit;
 }
 
+static void report_ballooned_pages(struct hv_dynmem_device *dm)
+{
+	u32 actual = dm->num_pages_ballooned;
+	long inflated_kb = actual << (HV_HYP_PAGE_SHIFT - 10);
+
+	balloon_set_inflated_total(inflated_kb);
+}
+
 static void balloon_up(struct work_struct *dummy)
 {
 	unsigned int num_pages = dm_device.balloon_wrk.num_pages;
@@ -1368,6 +1376,7 @@ static void balloon_up(struct work_struct *dummy)
 		}
 	}
 
+	report_ballooned_pages(&dm_device);
 }
 
 static void balloon_down(struct hv_dynmem_device *dm,
@@ -1387,6 +1396,8 @@ static void balloon_down(struct hv_dynmem_device *dm,
 	pr_debug("Freed %u ballooned pages.\n",
 		prev_pages_ballooned - dm->num_pages_ballooned);
 
+	report_ballooned_pages(dm);
+
 	if (req->more_pages == 1)
 		return;
 
-- 
2.31.1