From: Wei Wang <wei.w.wang@intel.com>
To: virtio-dev@lists.oasis-open.org, linux-kernel@vger.kernel.org,
qemu-devel@nongnu.org, virtualization@lists.linux-foundation.org,
kvm@vger.kernel.org, linux-mm@kvack.org, mst@redhat.com,
mhocko@kernel.org, akpm@linux-foundation.org,
mawilcox@microsoft.com
Cc: david@redhat.com, penguin-kernel@I-love.SAKURA.ne.jp,
cornelia.huck@de.ibm.com, mgorman@techsingularity.net,
aarcange@redhat.com, amit.shah@redhat.com, pbonzini@redhat.com,
willy@infradead.org, wei.w.wang@intel.com,
liliang.opensource@gmail.com, yang.zhang.wz@gmail.com,
quan.xu0@gmail.com, nilal@redhat.com, riel@redhat.com
Subject: [PATCH v21 5/5] virtio-balloon: don't report free pages when page poisoning is enabled
Date: Tue, 9 Jan 2018 19:11:02 +0800 [thread overview]
Message-ID: <1515496262-7533-6-git-send-email-wei.w.wang@intel.com> (raw)
In-Reply-To: <1515496262-7533-1-git-send-email-wei.w.wang@intel.com>
The guest free pages should not be discarded by the live migration thread
when page poisoning is enabled with PAGE_POISONING_NO_SANITY=n, because
skipping the transfer of such poisoned free pages will trigger false
positive when new pages are allocated and checked on the destination.
This patch adds a config field, poison_val. Guest writes to the config
field to tell the host about the poisoning value. The value will be 0 in
the following cases:
1) PAGE_POISONING_NO_SANITY is enabled;
2) page poisoning is disabled; or
3) PAGE_POISONING_ZERO is enabled.
Signed-off-by: Wei Wang <wei.w.wang@intel.com>
Suggested-by: Michael S. Tsirkin <mst@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
---
drivers/virtio/virtio_balloon.c | 8 ++++++++
include/uapi/linux/virtio_balloon.h | 2 ++
2 files changed, 10 insertions(+)
diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index f7e8830..7429894 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -859,6 +859,7 @@ static struct file_system_type balloon_fs = {
static int virtballoon_probe(struct virtio_device *vdev)
{
struct virtio_balloon *vb;
+ __u32 poison_val;
int err;
if (!vdev->config->get) {
@@ -896,6 +897,13 @@ static int virtballoon_probe(struct virtio_device *vdev)
WQ_FREEZABLE | WQ_CPU_INTENSIVE, 0);
INIT_WORK(&vb->report_free_page_work, report_free_page);
vb->stop_cmd_id = VIRTIO_BALLOON_FREE_PAGE_REPORT_STOP_ID;
+ if (IS_ENABLED(CONFIG_PAGE_POISONING_NO_SANITY) ||
+ !page_poisoning_enabled())
+ poison_val = 0;
+ else
+ poison_val = PAGE_POISON;
+ virtio_cwrite(vb->vdev, struct virtio_balloon_config,
+ poison_val, &poison_val);
}
vb->nb.notifier_call = virtballoon_oom_notify;
diff --git a/include/uapi/linux/virtio_balloon.h b/include/uapi/linux/virtio_balloon.h
index 58f1274..f270e9e 100644
--- a/include/uapi/linux/virtio_balloon.h
+++ b/include/uapi/linux/virtio_balloon.h
@@ -48,6 +48,8 @@ struct virtio_balloon_config {
__u32 actual;
/* Free page report command id, readonly by guest */
__u32 free_page_report_cmd_id;
+ /* Stores PAGE_POISON if page poisoning with sanity check is in use */
+ __u32 poison_val;
};
#define VIRTIO_BALLOON_S_SWAP_IN 0 /* Amount of memory swapped in */
--
2.7.4
prev parent reply other threads:[~2018-01-09 11:30 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-09 11:10 [PATCH v21 0/5] Virtio-balloon Enhancement Wei Wang
2018-01-09 11:10 ` [PATCH v21 1/5] xbitmap: Introduce xbitmap Wei Wang
2018-02-16 17:44 ` Andy Shevchenko
2018-02-16 18:30 ` Matthew Wilcox
2018-02-16 21:45 ` Andy Shevchenko
2018-02-16 21:58 ` Matthew Wilcox
2018-01-09 11:10 ` [PATCH v21 2/5] virtio-balloon: VIRTIO_BALLOON_F_SG Wei Wang
2018-01-09 11:11 ` [PATCH v21 3/5] mm: support reporting free page blocks Wei Wang
2018-01-09 11:11 ` [PATCH v21 4/5] virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_VQ Wei Wang
2018-01-09 11:11 ` Wei Wang [this message]
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