From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 97F1EC74A4B for ; Thu, 11 Jul 2019 08:49:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6D4C7208E4 for ; Thu, 11 Jul 2019 08:49:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728249AbfGKItc (ORCPT ); Thu, 11 Jul 2019 04:49:32 -0400 Received: from mx1.redhat.com ([209.132.183.28]:47194 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725963AbfGKItb (ORCPT ); Thu, 11 Jul 2019 04:49:31 -0400 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 13A2D81F07; Thu, 11 Jul 2019 08:49:30 +0000 (UTC) Received: from gondolin (ovpn-117-213.ams2.redhat.com [10.36.117.213]) by smtp.corp.redhat.com (Postfix) with ESMTP id 324321001B05; Thu, 11 Jul 2019 08:49:15 +0000 (UTC) Date: Thu, 11 Jul 2019 10:49:12 +0200 From: Cornelia Huck To: Nitesh Narayan Lal Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, pbonzini@redhat.com, lcapitulino@redhat.com, pagupta@redhat.com, wei.w.wang@intel.com, yang.zhang.wz@gmail.com, riel@surriel.com, david@redhat.com, mst@redhat.com, dodgen@google.com, konrad.wilk@oracle.com, dhildenb@redhat.com, aarcange@redhat.com, alexander.duyck@gmail.com, john.starks@microsoft.com, dave.hansen@intel.com, mhocko@suse.com Subject: Re: [QEMU Patch] virtio-baloon: Support for page hinting Message-ID: <20190711104912.2cd79aeb.cohuck@redhat.com> In-Reply-To: <20190710195303.19690-1-nitesh@redhat.com> References: <20190710195158.19640-1-nitesh@redhat.com> <20190710195303.19690-1-nitesh@redhat.com> Organization: Red Hat GmbH MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Thu, 11 Jul 2019 08:49:31 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 10 Jul 2019 15:53:03 -0400 Nitesh Narayan Lal wrote: $SUBJECT: s/baloon/balloon/ > Enables QEMU to perform madvise free on the memory range reported > by the vm. [No comments on the actual functionality; just some stuff I noticed.] > > Signed-off-by: Nitesh Narayan Lal > --- > hw/virtio/trace-events | 1 + > hw/virtio/virtio-balloon.c | 59 +++++++++++++++++++ > include/hw/virtio/virtio-balloon.h | 2 +- > include/qemu/osdep.h | 7 +++ > .../standard-headers/linux/virtio_balloon.h | 1 + > 5 files changed, 69 insertions(+), 1 deletion(-) > (...) > diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c > index 2112874055..5d186707b5 100644 > --- a/hw/virtio/virtio-balloon.c > +++ b/hw/virtio/virtio-balloon.c > @@ -34,6 +34,9 @@ > > #define BALLOON_PAGE_SIZE (1 << VIRTIO_BALLOON_PFN_SHIFT) > > +#define VIRTIO_BALLOON_PAGE_HINTING_MAX_PAGES 16 > +void free_mem_range(uint64_t addr, uint64_t len); > + > struct PartiallyBalloonedPage { > RAMBlock *rb; > ram_addr_t base; > @@ -328,6 +331,58 @@ static void balloon_stats_set_poll_interval(Object *obj, Visitor *v, > balloon_stats_change_timer(s, 0); > } > > +void free_mem_range(uint64_t addr, uint64_t len) > +{ > + int ret = 0; > + void *hvaddr_to_free; > + MemoryRegionSection mrs = memory_region_find(get_system_memory(), > + addr, 1); > + if (!mrs.mr) { > + warn_report("%s:No memory is mapped at address 0x%lu", __func__, addr); Indentation seems to be off here (also in other places; please double check.) > + return; > + } > + > + if (!memory_region_is_ram(mrs.mr) && !memory_region_is_romd(mrs.mr)) { > + warn_report("%s:Memory at address 0x%s is not RAM:0x%lu", __func__, > + HWADDR_PRIx, addr); > + memory_region_unref(mrs.mr); > + return; > + } > + > + hvaddr_to_free = qemu_map_ram_ptr(mrs.mr->ram_block, mrs.offset_within_region); > + trace_virtio_balloon_hinting_request(addr, len); > + ret = qemu_madvise(hvaddr_to_free,len, QEMU_MADV_FREE); > + if (ret == -1) { > + warn_report("%s: Madvise failed with error:%d", __func__, ret); > + } > +} > + > +static void virtio_balloon_handle_page_hinting(VirtIODevice *vdev, > + VirtQueue *vq) > +{ > + VirtQueueElement *elem; > + size_t offset = 0; > + uint64_t gpa, len; > + elem = virtqueue_pop(vq, sizeof(VirtQueueElement)); > + if (!elem) { > + return; > + } > + /* For pending hints which are < max_pages(16), 'gpa != 0' ensures that we > + * only read the buffer which holds a valid PFN value. > + * TODO: Find a better way to do this. > + */ > + while (iov_to_buf(elem->out_sg, elem->out_num, offset, &gpa, 8) == 8 && gpa != 0) { > + offset += 8; > + offset += iov_to_buf(elem->out_sg, elem->out_num, offset, &len, 8); > + if (!qemu_balloon_is_inhibited()) { > + free_mem_range(gpa, len); > + } > + } > + virtqueue_push(vq, elem, offset); > + virtio_notify(vdev, vq); > + g_free(elem); > +} > + > static void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq) > { > VirtIOBalloon *s = VIRTIO_BALLOON(vdev); > @@ -694,6 +749,7 @@ static uint64_t virtio_balloon_get_features(VirtIODevice *vdev, uint64_t f, > VirtIOBalloon *dev = VIRTIO_BALLOON(vdev); > f |= dev->host_features; > virtio_add_feature(&f, VIRTIO_BALLOON_F_STATS_VQ); > + virtio_add_feature(&f, VIRTIO_BALLOON_F_HINTING); I don't think you can add this unconditionally if you want to keep this migratable. This should be done via a property (as for deflate-on-oom and free-page-hint) so it can be turned off in compat machines. > > return f; > } > @@ -780,6 +836,7 @@ static void virtio_balloon_device_realize(DeviceState *dev, Error **errp) > s->ivq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output); > s->dvq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output); > s->svq = virtio_add_queue(vdev, 128, virtio_balloon_receive_stats); > + s->hvq = virtio_add_queue(vdev, 128, virtio_balloon_handle_page_hinting); This should probably be conditional in the same way as the free page hint queue (also see above). > > if (virtio_has_feature(s->host_features, > VIRTIO_BALLOON_F_FREE_PAGE_HINT)) { > @@ -875,6 +932,8 @@ static void virtio_balloon_instance_init(Object *obj) > > object_property_add(obj, "guest-stats", "guest statistics", > balloon_stats_get_all, NULL, NULL, s, NULL); > + object_property_add(obj, "guest-page-hinting", "guest page hinting", > + NULL, NULL, NULL, s, NULL); This object does not have any accessors; what purpose does it serve? > > object_property_add(obj, "guest-stats-polling-interval", "int", > balloon_stats_get_poll_interval, (...) > diff --git a/include/standard-headers/linux/virtio_balloon.h b/include/standard-headers/linux/virtio_balloon.h > index 9375ca2a70..f9e3e82562 100644 > --- a/include/standard-headers/linux/virtio_balloon.h > +++ b/include/standard-headers/linux/virtio_balloon.h > @@ -36,6 +36,7 @@ > #define VIRTIO_BALLOON_F_DEFLATE_ON_OOM 2 /* Deflate balloon on OOM */ > #define VIRTIO_BALLOON_F_FREE_PAGE_HINT 3 /* VQ to report free pages */ > #define VIRTIO_BALLOON_F_PAGE_POISON 4 /* Guest is using page poisoning */ > +#define VIRTIO_BALLOON_F_HINTING 5 /* Page hinting virtqueue */ > > /* Size of a PFN in the balloon interface. */ > #define VIRTIO_BALLOON_PFN_SHIFT 12 Please split off any update to these headers into a separate patch, so that it can be replaced by a proper headers update when it is merged.