This series provides an asynchronous means of reporting free guest pages
to QEMU through virtio-balloon so that the memory associated with those
pages can be dropped and reused by other processes and/or guests on the
host. Using this it is possible to avoid unnecessary I/O to disk and
greatly improve performance in the case of memory overcommit on the host.

I originally submitted this patch series[1] back on February 11th 2020,
but at that time I was focused primarily on the kernel portion of this
patch set. However as of April 7th those patches are now included in
Linus's kernel tree[2] and so I thought I should resubmit the QEMU side of
this for inclusion so that the feature will be available in QEMU hopefully
by the time the 5.7 kernel tree is released.

[1]: https://lore.kernel.org/lkml/20200211224416.29318.44077.stgit@localhost.localdomain/
[2]: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b0c504f154718904ae49349147e3b7e6ae91ffdc

---

Alexander Duyck (3):
      virtio-balloon: Implement support for page poison tracking feature
      virtio-balloon: Add support for providing free page reports to host
      virtio-balloon: Provide a interface for free page reporting


 hw/virtio/virtio-balloon.c                      |   67 ++++++++++++++++++++++-
 include/hw/virtio/virtio-balloon.h              |    3 +
 include/standard-headers/linux/virtio_balloon.h |    1 
 3 files changed, 66 insertions(+), 5 deletions(-)

--

Patchew URL: https://patchew.org/QEMU/20200408194628.24143.51644.stgit@localhost.localdomain/



Hi,

This series seems to have some coding style problems. See output below for
more information:

Subject: [PATCH v17 RESUBMIT QEMU 0/3] virtio-balloon: add support for providing free page reporting
Message-id: 20200408194628.24143.51644.stgit@localhost.localdomain
Type: series

=== TEST SCRIPT BEGIN ===
#!/bin/bash
git rev-parse base > /dev/null || exit 0
git config --local diff.renamelimit 0
git config --local diff.renames True
git config --local diff.algorithm histogram
./scripts/checkpatch.pl --mailback base..
=== TEST SCRIPT END ===

Updating 3c8cf5a9c21ff8782164d1def7f44bd888713384
Switched to a new branch 'test'
c1e1e4c virtio-balloon: Provide a interface for free page reporting
c3fc4c5 virtio-balloon: Add support for providing free page reports to host
3410f65 virtio-balloon: Implement support for page poison tracking feature

=== OUTPUT BEGIN ===
1/3 Checking commit 3410f6599211 (virtio-balloon: Implement support for page poison tracking feature)
ERROR: trailing whitespace
#68: FILE: hw/virtio/virtio-balloon.c:708:
+    dev->poison_val = virtio_vdev_has_feature(vdev, VIRTIO_BALLOON_F_PAGE_POISON) ? $

WARNING: line over 80 characters
#68: FILE: hw/virtio/virtio-balloon.c:708:
+    dev->poison_val = virtio_vdev_has_feature(vdev, VIRTIO_BALLOON_F_PAGE_POISON) ? 

total: 1 errors, 1 warnings, 76 lines checked

Patch 1/3 has style problems, please review.  If any of these errors
are false positives report them to the maintainer, see
CHECKPATCH in MAINTAINERS.

2/3 Checking commit c3fc4c5a9fc3 (virtio-balloon: Add support for providing free page reports to host)
3/3 Checking commit c1e1e4c7f3d1 (virtio-balloon: Provide a interface for free page reporting)
ERROR: code indent should never use tabs
#36: FILE: hw/virtio/virtio-balloon.c:330:
+    ^Iunsigned int i;$

ERROR: braces {} are necessary for all arms of this statement
#45: FILE: hw/virtio/virtio-balloon.c:339:
+            if (qemu_balloon_is_inhibited() || dev->poison_val)
[...]

ERROR: braces {} are necessary for all arms of this statement
#52: FILE: hw/virtio/virtio-balloon.c:346:
+            if ((ram_offset | size) & (rb_page_size - 1))
[...]

total: 3 errors, 0 warnings, 84 lines checked

Patch 3/3 has style problems, please review.  If any of these errors
are false positives report them to the maintainer, see
CHECKPATCH in MAINTAINERS.

=== OUTPUT END ===

Test command exited with code: 1


The full log is available at
http://patchew.org/logs/20200408194628.24143.51644.stgit@localhost.localdomain/testing.checkpatch/?type=message.
---
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