From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f70.google.com (mail-pg0-f70.google.com [74.125.83.70]) by kanga.kvack.org (Postfix) with ESMTP id 4C0EF280282 for ; Wed, 17 Jan 2018 00:28:34 -0500 (EST) Received: by mail-pg0-f70.google.com with SMTP id j6so10665221pgp.21 for ; Tue, 16 Jan 2018 21:28:34 -0800 (PST) Received: from mga06.intel.com (mga06.intel.com. [134.134.136.31]) by mx.google.com with ESMTPS id f90si2020199plb.641.2018.01.16.21.28.32 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 16 Jan 2018 21:28:33 -0800 (PST) From: Wei Wang Subject: [PATCH v22 3/3] virtio-balloon: don't report free pages when page poisoning is enabled Date: Wed, 17 Jan 2018 13:10:12 +0800 Message-Id: <1516165812-3995-4-git-send-email-wei.w.wang@intel.com> In-Reply-To: <1516165812-3995-1-git-send-email-wei.w.wang@intel.com> References: <1516165812-3995-1-git-send-email-wei.w.wang@intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: virtio-dev@lists.oasis-open.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, kvm@vger.kernel.org, linux-mm@kvack.org, mst@redhat.com, mhocko@kernel.org, akpm@linux-foundation.org Cc: pbonzini@redhat.com, wei.w.wang@intel.com, liliang.opensource@gmail.com, yang.zhang.wz@gmail.com, quan.xu0@gmail.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 b9561a5..5a42235 100644 --- a/drivers/virtio/virtio_balloon.c +++ b/drivers/virtio/virtio_balloon.c @@ -706,6 +706,7 @@ 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) { @@ -740,6 +741,13 @@ static int virtballoon_probe(struct virtio_device *vdev) WQ_FREEZABLE | WQ_CPU_INTENSIVE, 0); INIT_WORK(&vb->report_free_page_work, report_free_page_func); 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 55e2456..5861876 100644 --- a/include/uapi/linux/virtio_balloon.h +++ b/include/uapi/linux/virtio_balloon.h @@ -47,6 +47,8 @@ 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 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org