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On Fri, Oct 20, 2017 at 07:54:25PM +0800, Wei Wang wrote: > The current implementation only deflates 256 pages even when a user > specifies more than that via the oom_pages module param. This patch > enables the deflating of up to oom_pages pages if there are enough > inflated pages. > > Signed-off-by: Wei Wang <wei.w.wang at intel.com> > Cc: Michael S. Tsirkin <mst at redhat.com> > Cc: Michal Hocko <mhocko at kernel.org> > Cc...

On Fri, Oct 20, 2017 at 07:54:25PM +0800, Wei Wang wrote: > The current implementation only deflates 256 pages even when a user > specifies more than that via the oom_pages module param. This patch > enables the deflating of up to oom_pages pages if there are enough > inflated pages. > > Signed-off-by: Wei Wang <wei.w.wang at intel.com> > Cc: Michael S. Tsirkin <mst at redhat.com> > Cc: Michal Hocko <mhocko at kernel.org> > Cc...

The current implementation only deflates 256 pages even when a user specifies more than that via the oom_pages module param. This patch enables the deflating of up to oom_pages pages if there are enough inflated pages. Signed-off-by: Wei Wang <wei.w.wang at intel.com> Cc: Michael S. Tsirkin <mst at redhat.com> Cc: Michal Hocko <mhocko at kernel.org> Cc: Tetsuo Handa <penguin-kernel a...

Michael S. Tsirkin wrote: > On Fri, Oct 20, 2017 at 07:54:25PM +0800, Wei Wang wrote: > > The current implementation only deflates 256 pages even when a user > > specifies more than that via the oom_pages module param. This patch > > enables the deflating of up to oom_pages pages if there are enough > > inflated pages. > > This seems reasonable. Does this by itself help? At least > > - num_freed_pages = leak_balloon(vb, oom_pages); > > + > > + /* Don't de...

...up. */ __le32 num_pages; /* Number of pages we've actually got in balloon. */ diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c index 3176ea4..0413157 100644 --- a/drivers/virtio/virtio_balloon.c +++ b/drivers/virtio/virtio_balloon.c @@ -44,8 +44,7 @@ static int oom_pages = OOM_VBALLOON_DEFAULT_PAGES; module_param(oom_pages, int, S_IRUSR | S_IWUSR); MODULE_PARM_DESC(oom_pages, "pages to free on OOM"); -struct virtio_balloon -{ +struct virtio_balloon { struct virtio_device *vdev; struct virtqueue *inflate_vq, *deflate_vq, *stats_vq; -- MST

...up. */ __le32 num_pages; /* Number of pages we've actually got in balloon. */ diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c index 3176ea4..0413157 100644 --- a/drivers/virtio/virtio_balloon.c +++ b/drivers/virtio/virtio_balloon.c @@ -44,8 +44,7 @@ static int oom_pages = OOM_VBALLOON_DEFAULT_PAGES; module_param(oom_pages, int, S_IRUSR | S_IWUSR); MODULE_PARM_DESC(oom_pages, "pages to free on OOM"); -struct virtio_balloon -{ +struct virtio_balloon { struct virtio_device *vdev; struct virtqueue *inflate_vq, *deflate_vq, *stats_vq; -- MST

...n.c > @@ -42,6 +42,10 @@ > #define OOM_VBALLOON_DEFAULT_PAGES 256 > #define VIRTBALLOON_OOM_NOTIFY_PRIORITY 80 > > +#define PAGE_BMAP_SIZE (8 * PAGE_SIZE) > +#define PFNS_PER_PAGE_BMAP (PAGE_BMAP_SIZE * BITS_PER_BYTE) > +#define PAGE_BMAP_COUNT_MAX 32 > + > static int oom_pages = OOM_VBALLOON_DEFAULT_PAGES; > module_param(oom_pages, int, S_IRUSR | S_IWUSR); > MODULE_PARM_DESC(oom_pages, "pages to free on OOM"); @@ -50,6 +54,14 > @@ MODULE_PARM_DESC(oom_pages, "pages to free on OOM"); static struct > vfsmount *balloon_mnt; #endif > &...

...n.c > @@ -42,6 +42,10 @@ > #define OOM_VBALLOON_DEFAULT_PAGES 256 > #define VIRTBALLOON_OOM_NOTIFY_PRIORITY 80 > > +#define PAGE_BMAP_SIZE (8 * PAGE_SIZE) > +#define PFNS_PER_PAGE_BMAP (PAGE_BMAP_SIZE * BITS_PER_BYTE) > +#define PAGE_BMAP_COUNT_MAX 32 > + > static int oom_pages = OOM_VBALLOON_DEFAULT_PAGES; > module_param(oom_pages, int, S_IRUSR | S_IWUSR); > MODULE_PARM_DESC(oom_pages, "pages to free on OOM"); @@ -50,6 +54,14 > @@ MODULE_PARM_DESC(oom_pages, "pages to free on OOM"); static struct > vfsmount *balloon_mnt; #endif > &...

...by the inability to run leak_balloon and fill_balloon concurrently; 2) enable OOM to release more than 256 inflated pages; and 3) stop inflating when the guest is under severe memory pressure (i.e. OOM). Here is an example of the benefit brought by this patch series: The guest sets virtio_balloon.oom_pages=100000. When the host requests to inflate 7.9G of an 8G idle guest, the guest can still run normally since OOM can guarantee at least 100000 pages (400MB) for the guest. Without the above patches, the guest will kill all the killable processes and fall into kernel panic finally. Wei Wang (3):...

...by the inability to run leak_balloon and fill_balloon concurrently; 2) enable OOM to release more than 256 inflated pages; and 3) stop inflating when the guest is under severe memory pressure (i.e. OOM). Here is an example of the benefit brought by this patch series: The guest sets virtio_balloon.oom_pages=100000. When the host requests to inflate 7.9G of an 8G idle guest, the guest can still run normally since OOM can guarantee at least 100000 pages (400MB) for the guest. Without the above patches, the guest will kill all the killable processes and fall into kernel panic finally. Wei Wang (3):...

...virtio_balloon.c > @@ -43,6 +43,9 @@ > #define OOM_VBALLOON_DEFAULT_PAGES 256 > #define VIRTBALLOON_OOM_NOTIFY_PRIORITY 80 > > +/* The size of memory in bytes allocated for reporting free page hints */ > +#define FREE_PAGE_HINT_MEM_SIZE (PAGE_SIZE * 16) > + > static int oom_pages = OOM_VBALLOON_DEFAULT_PAGES; > module_param(oom_pages, int, S_IRUSR | S_IWUSR); > MODULE_PARM_DESC(oom_pages, "pages to free on OOM"); Doesn't this limit memory size of the guest we can report? Apparently to several gigabytes ... OTOH huge guests with lots of free memory i...

...virtio_balloon.c > @@ -43,6 +43,9 @@ > #define OOM_VBALLOON_DEFAULT_PAGES 256 > #define VIRTBALLOON_OOM_NOTIFY_PRIORITY 80 > > +/* The size of memory in bytes allocated for reporting free page hints */ > +#define FREE_PAGE_HINT_MEM_SIZE (PAGE_SIZE * 16) > + > static int oom_pages = OOM_VBALLOON_DEFAULT_PAGES; > module_param(oom_pages, int, S_IRUSR | S_IWUSR); > MODULE_PARM_DESC(oom_pages, "pages to free on OOM"); Doesn't this limit memory size of the guest we can report? Apparently to several gigabytes ... OTOH huge guests with lots of free memory i...

...256 #define > > > VIRTBALLOON_OOM_NOTIFY_PRIORITY 80 > > > > > > +#define PAGE_BMAP_SIZE (8 * PAGE_SIZE) > > > +#define PFNS_PER_PAGE_BMAP (PAGE_BMAP_SIZE * BITS_PER_BYTE) > > > +#define PAGE_BMAP_COUNT_MAX 32 > > > + > > > static int oom_pages = OOM_VBALLOON_DEFAULT_PAGES; > > > module_param(oom_pages, int, S_IRUSR | S_IWUSR); > > > MODULE_PARM_DESC(oom_pages, "pages to free on OOM"); @@ -50,6 > +54,14 > > > @@ MODULE_PARM_DESC(oom_pages, "pages to free on OOM"); static > > >...

...256 #define > > > VIRTBALLOON_OOM_NOTIFY_PRIORITY 80 > > > > > > +#define PAGE_BMAP_SIZE (8 * PAGE_SIZE) > > > +#define PFNS_PER_PAGE_BMAP (PAGE_BMAP_SIZE * BITS_PER_BYTE) > > > +#define PAGE_BMAP_COUNT_MAX 32 > > > + > > > static int oom_pages = OOM_VBALLOON_DEFAULT_PAGES; > > > module_param(oom_pages, int, S_IRUSR | S_IWUSR); > > > MODULE_PARM_DESC(oom_pages, "pages to free on OOM"); @@ -50,6 > +54,14 > > > @@ MODULE_PARM_DESC(oom_pages, "pages to free on OOM"); static > > >...

...VBALLOON_DEFAULT_PAGES 256 #define > > > VIRTBALLOON_OOM_NOTIFY_PRIORITY 80 > > > > > > +/* The size of memory in bytes allocated for reporting free page > > > +hints */ #define FREE_PAGE_HINT_MEM_SIZE (PAGE_SIZE * 16) > > > + > > > static int oom_pages = OOM_VBALLOON_DEFAULT_PAGES; > > > module_param(oom_pages, int, S_IRUSR | S_IWUSR); > > > MODULE_PARM_DESC(oom_pages, "pages to free on OOM"); > > > > Doesn't this limit memory size of the guest we can report? > > Apparently to several gigabytes...

...VBALLOON_DEFAULT_PAGES 256 #define > > > VIRTBALLOON_OOM_NOTIFY_PRIORITY 80 > > > > > > +/* The size of memory in bytes allocated for reporting free page > > > +hints */ #define FREE_PAGE_HINT_MEM_SIZE (PAGE_SIZE * 16) > > > + > > > static int oom_pages = OOM_VBALLOON_DEFAULT_PAGES; > > > module_param(oom_pages, int, S_IRUSR | S_IWUSR); > > > MODULE_PARM_DESC(oom_pages, "pages to free on OOM"); > > > > Doesn't this limit memory size of the guest we can report? > > Apparently to several gigabytes...

...th several times. To reduce the > + * overhead of scanning the page list. VIRTIO_BALLOON_PFNS_LIMIT should > + * be set with a value which can cover most cases. > + */ > +#define VIRTIO_BALLOON_PFNS_LIMIT ((32 * (1ULL << 30)) >> PAGE_SHIFT) /* 32GB */ > + > static int oom_pages = OOM_VBALLOON_DEFAULT_PAGES; > module_param(oom_pages, int, S_IRUSR | S_IWUSR); > MODULE_PARM_DESC(oom_pages, "pages to free on OOM"); > > +extern unsigned long get_max_pfn(void); > + Please just include the correct header. No need for this hackery. > struct vi...

...th several times. To reduce the > + * overhead of scanning the page list. VIRTIO_BALLOON_PFNS_LIMIT should > + * be set with a value which can cover most cases. > + */ > +#define VIRTIO_BALLOON_PFNS_LIMIT ((32 * (1ULL << 30)) >> PAGE_SHIFT) /* 32GB */ > + > static int oom_pages = OOM_VBALLOON_DEFAULT_PAGES; > module_param(oom_pages, int, S_IRUSR | S_IWUSR); > MODULE_PARM_DESC(oom_pages, "pages to free on OOM"); > > +extern unsigned long get_max_pfn(void); > + Please just include the correct header. No need for this hackery. > struct vi...

...define OOM_VBALLOON_DEFAULT_PAGES 256 > > #define VIRTBALLOON_OOM_NOTIFY_PRIORITY 80 > > > > +#define PAGE_BMAP_SIZE (8 * PAGE_SIZE) > > +#define PFNS_PER_PAGE_BMAP (PAGE_BMAP_SIZE * BITS_PER_BYTE) > > +#define PAGE_BMAP_COUNT_MAX 32 > > + > > static int oom_pages = OOM_VBALLOON_DEFAULT_PAGES; > > module_param(oom_pages, int, S_IRUSR | S_IWUSR); > > MODULE_PARM_DESC(oom_pages, "pages to free on OOM"); @@ -50,6 +54,14 > > @@ MODULE_PARM_DESC(oom_pages, "pages to free on OOM"); static struct > > vfsmount *balloon_...

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