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, UNPARSEABLE_RELAY 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 70D93C10F29 for ; Tue, 17 Mar 2020 10:13:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2BD6F20714 for ; Tue, 17 Mar 2020 10:13:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726121AbgCQKN5 convert rfc822-to-8bit (ORCPT ); Tue, 17 Mar 2020 06:13:57 -0400 Received: from out30-131.freemail.mail.aliyun.com ([115.124.30.131]:44763 "EHLO out30-131.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725730AbgCQKN4 (ORCPT ); Tue, 17 Mar 2020 06:13:56 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R161e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01f04452;MF=teawaterz@linux.alibaba.com;NM=1;PH=DS;RN=11;SR=0;TI=SMTPD_---0Tss.xHA_1584440013; Received: from 127.0.0.1(mailfrom:teawaterz@linux.alibaba.com fp:SMTPD_---0Tss.xHA_1584440013) by smtp.aliyun-inc.com(127.0.0.1); Tue, 17 Mar 2020 18:13:38 +0800 Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 13.0 \(3608.60.0.2.5\)) Subject: Re: [RFC for QEMU] virtio-balloon: Add option thp-order to set VIRTIO_BALLOON_F_THP_ORDER From: teawater In-Reply-To: <20200312042340-mutt-send-email-mst@kernel.org> Date: Tue, 17 Mar 2020 18:13:32 +0800 Cc: Hui Zhu , jasowang@redhat.com, akpm@linux-foundation.org, pagupta@redhat.com, mojha@codeaurora.org, david@redhat.com, namit@vmware.com, virtualization@lists.linux-foundation.org, linux-kernel@vger.kernel.org, qemu-devel@nongnu.org Content-Transfer-Encoding: 8BIT Message-Id: References: <1583999395-9131-1-git-send-email-teawater@gmail.com> <1583999395-9131-2-git-send-email-teawater@gmail.com> <20200312042340-mutt-send-email-mst@kernel.org> To: "Michael S. Tsirkin" X-Mailer: Apple Mail (2.3608.60.0.2.5) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > 2020年3月12日 16:25，Michael S. Tsirkin 写道： > > On Thu, Mar 12, 2020 at 03:49:55PM +0800, Hui Zhu wrote: >> If the guest kernel has many fragmentation pages, use virtio_balloon >> will split THP of QEMU when it calls MADV_DONTNEED madvise to release >> the balloon pages. >> Set option thp-order to on will open flags VIRTIO_BALLOON_F_THP_ORDER. >> It will set balloon size to THP size to handle the THP split issue. >> >> Signed-off-by: Hui Zhu > > What's wrong with just using the PartiallyBalloonedPage machinery > instead? That would make it guest transparent. In balloon_inflate_page: rb_page_size = qemu_ram_pagesize(rb); if (rb_page_size == BALLOON_PAGE_SIZE) { /* Easy case */ It seems that PartiallyBalloonedPage is only used when rb_page_size is greater than BALLOON_PAGE_SIZE. Do you mean I should modify the working mechanism of balloon_inflate_page function? Thanks, Hui > >> --- >> hw/virtio/virtio-balloon.c | 67 ++++++++++++++++--------- >> include/standard-headers/linux/virtio_balloon.h | 4 ++ >> 2 files changed, 47 insertions(+), 24 deletions(-) >> >> diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c >> index a4729f7..cfe86b0 100644 >> --- a/hw/virtio/virtio-balloon.c >> +++ b/hw/virtio/virtio-balloon.c >> @@ -340,37 +340,49 @@ static void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq) >> while (iov_to_buf(elem->out_sg, elem->out_num, offset, &pfn, 4) == 4) { >> unsigned int p = virtio_ldl_p(vdev, &pfn); >> hwaddr pa; >> + size_t handle_size = BALLOON_PAGE_SIZE; >> >> pa = (hwaddr) p << VIRTIO_BALLOON_PFN_SHIFT; >> offset += 4; >> >> - section = memory_region_find(get_system_memory(), pa, >> - BALLOON_PAGE_SIZE); >> - if (!section.mr) { >> - trace_virtio_balloon_bad_addr(pa); >> - continue; >> - } >> - if (!memory_region_is_ram(section.mr) || >> - memory_region_is_rom(section.mr) || >> - memory_region_is_romd(section.mr)) { >> - trace_virtio_balloon_bad_addr(pa); >> - memory_region_unref(section.mr); >> - continue; >> - } >> + if (virtio_has_feature(s->host_features, >> + VIRTIO_BALLOON_F_THP_ORDER)) >> + handle_size = BALLOON_PAGE_SIZE << VIRTIO_BALLOON_THP_ORDER; >> + >> + while (handle_size > 0) { >> + section = memory_region_find(get_system_memory(), pa, >> + BALLOON_PAGE_SIZE); >> + if (!section.mr) { >> + trace_virtio_balloon_bad_addr(pa); >> + continue; >> + } >> + if (!memory_region_is_ram(section.mr) || >> + memory_region_is_rom(section.mr) || >> + memory_region_is_romd(section.mr)) { >> + trace_virtio_balloon_bad_addr(pa); >> + memory_region_unref(section.mr); >> + continue; >> + } >> >> - trace_virtio_balloon_handle_output(memory_region_name(section.mr), >> - pa); >> - if (!qemu_balloon_is_inhibited()) { >> - if (vq == s->ivq) { >> - balloon_inflate_page(s, section.mr, >> - section.offset_within_region, &pbp); >> - } else if (vq == s->dvq) { >> - balloon_deflate_page(s, section.mr, section.offset_within_region); >> - } else { >> - g_assert_not_reached(); >> + trace_virtio_balloon_handle_output(memory_region_name(section.mr), >> + pa); >> + if (!qemu_balloon_is_inhibited()) { >> + if (vq == s->ivq) { >> + balloon_inflate_page(s, section.mr, >> + section.offset_within_region, >> + &pbp); >> + } else if (vq == s->dvq) { >> + balloon_deflate_page(s, section.mr, >> + section.offset_within_region); >> + } else { >> + g_assert_not_reached(); >> + } >> } >> + memory_region_unref(section.mr); >> + >> + pa += BALLOON_PAGE_SIZE; >> + handle_size -= BALLOON_PAGE_SIZE; >> } >> - memory_region_unref(section.mr); >> } >> >> virtqueue_push(vq, elem, offset); >> @@ -693,6 +705,8 @@ static void virtio_balloon_set_config(VirtIODevice *vdev, >> >> memcpy(&config, config_data, virtio_balloon_config_size(dev)); >> dev->actual = le32_to_cpu(config.actual); >> + if (virtio_has_feature(vdev->host_features, VIRTIO_BALLOON_F_THP_ORDER)) >> + dev->actual <<= VIRTIO_BALLOON_THP_ORDER; >> if (dev->actual != oldactual) { >> qapi_event_send_balloon_change(vm_ram_size - >> ((ram_addr_t) dev->actual << VIRTIO_BALLOON_PFN_SHIFT)); >> @@ -728,6 +742,9 @@ static void virtio_balloon_to_target(void *opaque, ram_addr_t target) >> } >> if (target) { >> dev->num_pages = (vm_ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT; >> + if (virtio_has_feature(dev->host_features, >> + VIRTIO_BALLOON_F_THP_ORDER)) >> + dev->num_pages >>= VIRTIO_BALLOON_THP_ORDER; >> virtio_notify_config(vdev); >> } >> trace_virtio_balloon_to_target(target, dev->num_pages); >> @@ -916,6 +933,8 @@ static Property virtio_balloon_properties[] = { >> VIRTIO_BALLOON_F_DEFLATE_ON_OOM, false), >> DEFINE_PROP_BIT("free-page-hint", VirtIOBalloon, host_features, >> VIRTIO_BALLOON_F_FREE_PAGE_HINT, false), >> + DEFINE_PROP_BIT("thp-order", VirtIOBalloon, host_features, >> + VIRTIO_BALLOON_F_THP_ORDER, false), >> /* QEMU 4.0 accidentally changed the config size even when free-page-hint >> * is disabled, resulting in QEMU 3.1 migration incompatibility. This >> * property retains this quirk for QEMU 4.1 machine types. >> diff --git a/include/standard-headers/linux/virtio_balloon.h b/include/standard-headers/linux/virtio_balloon.h >> index 9375ca2..f54d613 100644 >> --- a/include/standard-headers/linux/virtio_balloon.h >> +++ b/include/standard-headers/linux/virtio_balloon.h >> @@ -36,10 +36,14 @@ >> #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_THP_ORDER 5 /* Set balloon page order to thp order */ >> >> /* Size of a PFN in the balloon interface. */ >> #define VIRTIO_BALLOON_PFN_SHIFT 12 >> >> +/* The order of the balloon page */ >> +#define VIRTIO_BALLOON_THP_ORDER 9 >> + >> #define VIRTIO_BALLOON_CMD_ID_STOP 0 >> #define VIRTIO_BALLOON_CMD_ID_DONE 1 >> struct virtio_balloon_config { >> -- >> 2.7.4