similar to: [PATCH v3 0/2] virtio-balloon: some improvements

Two fixes for issues I stumbled over while working on patch #3. Switch back to the good ol' OOM handler for VIRTIO_BALLOON_F_DEFLATE_ON_OOM as the switch to the shrinker introduce some undesired side effects. Keep the shrinker in place to handle VIRTIO_BALLOON_F_FREE_PAGE_HINT. Lengthy discussion under [1]. I tested with QEMU and "deflate-on-oom=on". Works as expected. Did not test

This series is split from the "Virtio-balloon: support free page reporting" series to make some improvements. v1->v2 ChangeLog: - register the shrinker when VIRTIO_BALLOON_F_DEFLATE_ON_OOM is negotiated. Wei Wang (2): virtio-balloon: remove BUG() in init_vqs virtio_balloon: replace oom notifier with shrinker drivers/virtio/virtio_balloon.c | 125

This series is split from the "Virtio-balloon: support free page reporting" series to make some improvements. v1->v2 ChangeLog: - register the shrinker when VIRTIO_BALLOON_F_DEFLATE_ON_OOM is negotiated. Wei Wang (2): virtio-balloon: remove BUG() in init_vqs virtio_balloon: replace oom notifier with shrinker drivers/virtio/virtio_balloon.c | 125

This patch series is separated from the previous "Virtio-balloon Enhancement" series. The new feature, VIRTIO_BALLOON_F_FREE_PAGE_HINT, implemented by this series enables the virtio-balloon driver to report hints of guest free pages to the host. It can be used to accelerate live migration of VMs. Here is an introduction of this usage: Live migration needs to transfer the VM's

This patch series is separated from the previous "Virtio-balloon Enhancement" series. The new feature, VIRTIO_BALLOON_F_FREE_PAGE_HINT, implemented by this series enables the virtio-balloon driver to report hints of guest free pages to the host. It can be used to accelerate live migration of VMs. Here is an introduction of this usage: Live migration needs to transfer the VM's

On Wed, Feb 5, 2020 at 8:34 AM David Hildenbrand <david at redhat.com> wrote: > Commit 71994620bb25 ("virtio_balloon: replace oom notifier with shrinker") > changed the behavior when deflation happens automatically. Instead of > deflating when called by the OOM handler, the shrinker is used. > > However, the balloon is not simply some slab cache that should be >

On Wed, Feb 5, 2020 at 8:34 AM David Hildenbrand <david at redhat.com> wrote: > Commit 71994620bb25 ("virtio_balloon: replace oom notifier with shrinker") > changed the behavior when deflation happens automatically. Instead of > deflating when called by the OOM handler, the shrinker is used. > > However, the balloon is not simply some slab cache that should be >

@Andrew, as this fix is based on free page reporting, can this go through your tree? Patch #1 contains a proper description. v3 -> v4: - Add Ack from David Rientjes - Minor tweaks to test details in the patch description v2 -> v3: - Use vb->vdev instead of vdev in all feature checks. We'll clean the other ones up later. - Add one empty line virtballoon_probe() to make it look

On Fri, Jul 20, 2018 at 04:33:02PM +0800, Wei Wang wrote: > The OOM notifier is getting deprecated to use for the reasons mentioned > here by Michal Hocko: https://lkml.org/lkml/2018/7/12/314 > > This patch replaces the virtio-balloon oom notifier with a shrinker > to release balloon pages on memory pressure. > > In addition, the bug in the replaced virtballoon_oom_notify

On Fri, Jul 20, 2018 at 04:33:02PM +0800, Wei Wang wrote: > The OOM notifier is getting deprecated to use for the reasons mentioned > here by Michal Hocko: https://lkml.org/lkml/2018/7/12/314 > > This patch replaces the virtio-balloon oom notifier with a shrinker > to release balloon pages on memory pressure. > > In addition, the bug in the replaced virtballoon_oom_notify

Commit 71994620bb25 ("virtio_balloon: replace oom notifier with shrinker") changed the behavior when deflation happens automatically. Instead of deflating when called by the OOM handler, the shrinker is used. However, the balloon is not simply some other slab cache that should be shrunk when under memory pressure. The shrinker does not have a concept of priorities yet, so this behavior

Commit 71994620bb25 ("virtio_balloon: replace oom notifier with shrinker") changed the behavior when deflation happens automatically. Instead of deflating when called by the OOM handler, the shrinker is used. However, the balloon is not simply some other slab cache that should be shrunk when under memory pressure. The shrinker does not have a concept of priorities yet, so this behavior

Commit 71994620bb25 ("virtio_balloon: replace oom notifier with shrinker") changed the behavior when deflation happens automatically. Instead of deflating when called by the OOM handler, the shrinker is used. However, the balloon is not simply some other slab cache that should be shrunk when under memory pressure. The shrinker does not have a concept of priorities yet, so this behavior

Commit 71994620bb25 ("virtio_balloon: replace oom notifier with shrinker") changed the behavior when deflation happens automatically. Instead of deflating when called by the OOM handler, the shrinker is used. However, the balloon is not simply some other slab cache that should be shrunk when under memory pressure. The shrinker does not have a concept of priorities yet, so this behavior

On Fri, Aug 03, 2018 at 04:32:26PM +0800, Wei Wang wrote: > The OOM notifier is getting deprecated to use for the reasons: > - As a callout from the oom context, it is too subtle and easy to > generate bugs and corner cases which are hard to track; > - It is called too late (after the reclaiming has been performed). > Drivers with large amuont of reclaimable memory is expected

There are cases that users want to shrink balloon pages after the pagecache depleted. The conservative_shrinker lets the shrinker shrink balloon pages when all the pagecache has been reclaimed. Signed-off-by: Wei Wang <wei.w.wang at intel.com> --- drivers/virtio/virtio_balloon.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git

There are cases that users want to shrink balloon pages after the pagecache depleted. The conservative_shrinker lets the shrinker shrink balloon pages when all the pagecache has been reclaimed. Signed-off-by: Wei Wang <wei.w.wang at intel.com> --- drivers/virtio/virtio_balloon.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git

The OOM notifier is getting deprecated to use for the reasons: - As a callout from the oom context, it is too subtle and easy to generate bugs and corner cases which are hard to track; - It is called too late (after the reclaiming has been performed). Drivers with large amuont of reclaimable memory is expected to release them at an early stage of memory pressure; - The notifier callback

On Wed, Feb 05, 2020 at 05:34:02PM +0100, David Hildenbrand wrote: > Commit 71994620bb25 ("virtio_balloon: replace oom notifier with shrinker") > changed the behavior when deflation happens automatically. Instead of > deflating when called by the OOM handler, the shrinker is used. > > However, the balloon is not simply some slab cache that should be > shrunk when under

On Wed, Feb 05, 2020 at 05:34:02PM +0100, David Hildenbrand wrote: > Commit 71994620bb25 ("virtio_balloon: replace oom notifier with shrinker") > changed the behavior when deflation happens automatically. Instead of > deflating when called by the OOM handler, the shrinker is used. > > However, the balloon is not simply some slab cache that should be > shrunk when under