From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56635) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eOjQn-0007xs-Bc for qemu-devel@nongnu.org; Tue, 12 Dec 2017 07:13:09 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eOjQm-0006a2-9q for qemu-devel@nongnu.org; Tue, 12 Dec 2017 07:13:05 -0500 Received: from mga17.intel.com ([192.55.52.151]:39928) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1eOjQm-0006Pn-1H for qemu-devel@nongnu.org; Tue, 12 Dec 2017 07:13:04 -0500 From: Wei Wang Date: Tue, 12 Dec 2017 19:55:59 +0800 Message-Id: <1513079759-14169-8-git-send-email-wei.w.wang@intel.com> In-Reply-To: <1513079759-14169-1-git-send-email-wei.w.wang@intel.com> References: <1513079759-14169-1-git-send-email-wei.w.wang@intel.com> Subject: [Qemu-devel] [PATCH v19 7/7] virtio-balloon: don't report free pages when page poisoning is enabled List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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.xu@aliyun.com, nilal@redhat.com, riel@redhat.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 Suggested-by: Michael S. Tsirkin Cc: Michal Hocko --- 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 6e4f359..3050c9f 100644 --- a/drivers/virtio/virtio_balloon.c +++ b/drivers/virtio/virtio_balloon.c @@ -858,6 +858,7 @@ 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) { @@ -895,6 +896,13 @@ 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