Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752725AbaAPQZW (ORCPT ); Thu, 16 Jan 2014 11:25:22 -0500 Received: from mx1.redhat.com ([209.132.183.28]:6804 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752214AbaAPQYn (ORCPT ); Thu, 16 Jan 2014 11:24:43 -0500 From: Luiz Capitulino To: linux-kernel@vger.kernel.org Cc: kvm@vger.kernel.org, riel@redhat.com, aarcange@redhat.com, aquini@redhat.com, mst@redhat.com, rusty@rustcorp.com.au, vdavydov@parallels.com, amit.shah@redhat.com, dfediuck@redhat.com, agl@us.ibm.com Subject: [RFC PATCH 4/4] virtio_balloon: skip inflation if guest is under pressure Date: Thu, 16 Jan 2014 11:24:05 -0500 Message-Id: <1389889445-3855-5-git-send-email-lcapitulino@redhat.com> In-Reply-To: <1389889445-3855-1-git-send-email-lcapitulino@redhat.com> References: <1389889445-3855-1-git-send-email-lcapitulino@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Luiz capitulino This is necessary for automatic ballooning. If the guest gets under pressure while there's an on-going inflation operation, we want the guest to do the following: 1. Stop on-going inflation 2. Notify the host we're under pressure 3. Wait for host's acknowledge While the guest is waiting the host has the opportunity to reset num_pages to a value before the guest got into pressure. This will cancel current inflation. Signed-off-by: Luiz capitulino --- drivers/virtio/virtio_balloon.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c index 1c3ee71..7f5b7d2 100644 --- a/drivers/virtio/virtio_balloon.c +++ b/drivers/virtio/virtio_balloon.c @@ -188,8 +188,13 @@ static void fill_balloon(struct virtio_balloon *vb, size_t num) mutex_lock(&vb->balloon_lock); for (vb->num_pfns = 0; vb->num_pfns < num; vb->num_pfns += VIRTIO_BALLOON_PAGES_PER_PAGE) { - struct page *page = balloon_page_enqueue(vb_dev_info); + struct page *page; + if (guest_under_pressure(vb)) { + break; + } + + page = balloon_page_enqueue(vb_dev_info); if (!page) { dev_info_ratelimited(&vb->vdev->dev, "Out of puff! Can't get %u pages\n", -- 1.8.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/