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=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=unavailable 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 D403DC74A4B for ; Thu, 11 Jul 2019 11:13:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 98ECF21537 for ; Thu, 11 Jul 2019 11:13:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728102AbfGKLNj convert rfc822-to-8bit (ORCPT ); Thu, 11 Jul 2019 07:13:39 -0400 Received: from mx1.redhat.com ([209.132.183.28]:55850 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727929AbfGKLNj (ORCPT ); Thu, 11 Jul 2019 07:13:39 -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 7AF9A3082E8E; Thu, 11 Jul 2019 11:13:37 +0000 (UTC) Received: from [10.18.17.163] (dhcp-17-163.bos.redhat.com [10.18.17.163]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 491E31001F41; Thu, 11 Jul 2019 11:13:26 +0000 (UTC) Subject: Re: [QEMU Patch] virtio-baloon: Support for page hinting To: Cornelia Huck 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 References: <20190710195158.19640-1-nitesh@redhat.com> <20190710195303.19690-1-nitesh@redhat.com> <20190711104912.2cd79aeb.cohuck@redhat.com> From: Nitesh Narayan Lal Openpgp: preference=signencrypt Autocrypt: addr=nitesh@redhat.com; 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Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20190711104912.2cd79aeb.cohuck@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT Content-Language: en-US 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 [10.5.110.46]); Thu, 11 Jul 2019 11:13:38 +0000 (UTC) Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On 7/11/19 4:49 AM, Cornelia Huck wrote: > 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.) Thanks, I will check it. > >> + 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. I see, I will take a look at it. > >> >> 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). Makes sense. Thanks. > >> >> 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? I think its not required. I will correct this. > >> >> 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. I will do that. -- Thanks Nitesh