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=-13.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,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 2DC2CC4338F for ; Mon, 16 Aug 2021 05:37:27 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 82C79619EA for ; Mon, 16 Aug 2021 05:37:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 82C79619EA Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:36582 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mFVJN-0007gM-Eh for qemu-devel@archiver.kernel.org; Mon, 16 Aug 2021 01:37:25 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:58188) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mFVIh-00072K-40 for qemu-devel@nongnu.org; Mon, 16 Aug 2021 01:36:43 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:37844) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mFVId-00059n-Hk for qemu-devel@nongnu.org; Mon, 16 Aug 2021 01:36:42 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1629092197; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=BNwGhoDE7EVqMFhiX1rVhSfQTBD//vpwPljwAf+xdHI=; b=aX/5/kCJYyEpLvJADTEsywD25M/QkUodYnV38VpDCytbWkARTy68t1DHmG0tqfq/lOU98a TP8cSge3xOidfcrgTlChU3cgjBaHIlozJJd5dAWpDeOiev2jdFGSHYeoe1Z5UD9occFlb7 KMYUzsf122j3vFCjhwOVRE7Mew2/+7E= Received: from mail-wr1-f70.google.com (mail-wr1-f70.google.com [209.85.221.70]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-487-l6KCPWeKNgGJ08odZtTvZA-1; Mon, 16 Aug 2021 01:36:36 -0400 X-MC-Unique: l6KCPWeKNgGJ08odZtTvZA-1 Received: by mail-wr1-f70.google.com with SMTP id n18-20020adfe792000000b00156ae576abdso1358701wrm.9 for ; Sun, 15 Aug 2021 22:36:36 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:content-transfer-encoding :in-reply-to; bh=BNwGhoDE7EVqMFhiX1rVhSfQTBD//vpwPljwAf+xdHI=; b=RIGomZ86YWh0+Fp1O1hDvkEHZmQx5yVlCScBUxaOczhldbuzPD5+eqWQmnabeDbe/Z YCJeRulVvRbkeVQ/PzM4UlNBOFVQftPrnT1l8aET22x083fI+tax3Ur9Ba5qpmN0cy9Y xPPBZzJQCrSvtcx5xGGlkmmcfbsRhan5toVy1vQAvPd3F/NqqLWKqp9KdF0zD0FaJkTC htZNhIeR9f45sAjZMafl48Zg2NqsSzWRCzeWrXMMsnFS3Cz8OQPl6uUDAnyqgnf1E7wW JQsFMS/AFw0I/4QuJjQBQcQ8nekvis48R/4m5XP36f8iauAfN5d+0CX0TflJEXKsCuv3 OKHQ== X-Gm-Message-State: AOAM531oCydY8O+9xBi1mrb5/KNuaQBVY9RemSmeBCZcHJZeCOl3XFvU lPCJnrznZ74Iz9TihBprBU6qh4y1V47qrlaj0pxkZcOUrwaGZf03gbBRd6gAnTWV2RAsV/Yf+VW FELDy3deZO3Fmyh8= X-Received: by 2002:a5d:6e12:: with SMTP id h18mr16382305wrz.236.1629092195246; Sun, 15 Aug 2021 22:36:35 -0700 (PDT) X-Google-Smtp-Source: ABdhPJyWqeoMPYr3pN1b3jtt4bo1lqfv/l+yufdr64ytqXINik2LHaBnOWPHVWmFz6G6Vs5cTcNLmg== X-Received: by 2002:a5d:6e12:: with SMTP id h18mr16382285wrz.236.1629092195052; Sun, 15 Aug 2021 22:36:35 -0700 (PDT) Received: from redhat.com ([2.55.8.239]) by smtp.gmail.com with ESMTPSA id i8sm7239480wrv.70.2021.08.15.22.36.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 15 Aug 2021 22:36:33 -0700 (PDT) Date: Mon, 16 Aug 2021 01:36:30 -0400 From: "Michael S. Tsirkin" To: Jason Wang Subject: Re: [PATCH v3] vhost-vdpa: Do not send empty IOTLB update batches Message-ID: <20210816013610-mutt-send-email-mst@kernel.org> References: <20210812140933.226288-1-eperezma@redhat.com> MIME-Version: 1.0 In-Reply-To: Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=mst@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=216.205.24.124; envelope-from=mst@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -34 X-Spam_score: -3.5 X-Spam_bar: --- X-Spam_report: (-3.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.699, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Eugenio =?iso-8859-1?Q?P=E9rez?= , Eli Cohen , qemu-devel , Cindy Lu Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Mon, Aug 16, 2021 at 10:51:57AM +0800, Jason Wang wrote: > On Thu, Aug 12, 2021 at 10:09 PM Eugenio Pérez wrote: > > > > With the introduction of the batch hinting, meaningless batches can be > > created with no IOTLB updates if the memory region was skipped by > > vhost_vdpa_listener_skipped_section. This is the case of host notifiers > > memory regions, device un/realize, and others. This causes the vdpa > > device to receive dma mapping settings with no changes, a possibly > > expensive operation for nothing. > > > > To avoid that, VHOST_IOTLB_BATCH_BEGIN hint is delayed until we have a > > meaningful (not skipped section) mapping or unmapping operation, and > > VHOST_IOTLB_BATCH_END is not written unless at least one of _UPDATE / > > _INVALIDATE has been issued. > > Acked-by: Jason Wang Oops. You missed by pull request by a hairwidth. > > > > v3: > > * Use a bool instead of a counter avoiding potential number wrapping > > * Fix bad check on _commit > > * Move VHOST_BACKEND_F_IOTLB_BATCH check to > > vhost_vdpa_iotlb_batch_begin_once > > > > v2 (from RFC): > > * Rename misleading name > > * Abstract start batching function for listener_add/del > > > > Signed-off-by: Eugenio Pérez > > --- > > include/hw/virtio/vhost-vdpa.h | 1 + > > hw/virtio/vhost-vdpa.c | 35 ++++++++++++++++++++++------------ > > 2 files changed, 24 insertions(+), 12 deletions(-) > > > > diff --git a/include/hw/virtio/vhost-vdpa.h b/include/hw/virtio/vhost-vdpa.h > > index e98e327f12..6b9288fef8 100644 > > --- a/include/hw/virtio/vhost-vdpa.h > > +++ b/include/hw/virtio/vhost-vdpa.h > > @@ -23,6 +23,7 @@ typedef struct vhost_vdpa { > > int device_fd; > > int index; > > uint32_t msg_type; > > + bool iotlb_batch_begin_sent; > > MemoryListener listener; > > struct vhost_dev *dev; > > VhostVDPAHostNotifier notifier[VIRTIO_QUEUE_MAX]; > > diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c > > index 6ce94a1f4d..93b7db61d1 100644 > > --- a/hw/virtio/vhost-vdpa.c > > +++ b/hw/virtio/vhost-vdpa.c > > @@ -89,19 +89,13 @@ static int vhost_vdpa_dma_unmap(struct vhost_vdpa *v, hwaddr iova, > > return ret; > > } > > > > -static void vhost_vdpa_listener_begin(MemoryListener *listener) > > +static void vhost_vdpa_listener_begin_batch(struct vhost_vdpa *v) > > { > > - struct vhost_vdpa *v = container_of(listener, struct vhost_vdpa, listener); > > - struct vhost_dev *dev = v->dev; > > - struct vhost_msg_v2 msg = {}; > > int fd = v->device_fd; > > - > > - if (!(dev->backend_cap & (0x1ULL << VHOST_BACKEND_F_IOTLB_BATCH))) { > > - return; > > - } > > - > > - msg.type = v->msg_type; > > - msg.iotlb.type = VHOST_IOTLB_BATCH_BEGIN; > > + struct vhost_msg_v2 msg = { > > + .type = v->msg_type, > > + .iotlb.type = VHOST_IOTLB_BATCH_BEGIN, > > + }; > > > > if (write(fd, &msg, sizeof(msg)) != sizeof(msg)) { > > error_report("failed to write, fd=%d, errno=%d (%s)", > > @@ -109,6 +103,16 @@ static void vhost_vdpa_listener_begin(MemoryListener *listener) > > } > > } > > > > +static void vhost_vdpa_iotlb_batch_begin_once(struct vhost_vdpa *v) > > +{ > > + if (v->dev->backend_cap & (0x1ULL << VHOST_BACKEND_F_IOTLB_BATCH) && > > + !v->iotlb_batch_begin_sent) { > > + vhost_vdpa_listener_begin_batch(v); > > + } > > + > > + v->iotlb_batch_begin_sent = true; > > +} > > + > > static void vhost_vdpa_listener_commit(MemoryListener *listener) > > { > > struct vhost_vdpa *v = container_of(listener, struct vhost_vdpa, listener); > > @@ -120,6 +124,10 @@ static void vhost_vdpa_listener_commit(MemoryListener *listener) > > return; > > } > > > > + if (!v->iotlb_batch_begin_sent) { > > + return; > > + } > > + > > msg.type = v->msg_type; > > msg.iotlb.type = VHOST_IOTLB_BATCH_END; > > > > @@ -127,6 +135,8 @@ static void vhost_vdpa_listener_commit(MemoryListener *listener) > > error_report("failed to write, fd=%d, errno=%d (%s)", > > fd, errno, strerror(errno)); > > } > > + > > + v->iotlb_batch_begin_sent = false; > > } > > > > static void vhost_vdpa_listener_region_add(MemoryListener *listener, > > @@ -170,6 +180,7 @@ static void vhost_vdpa_listener_region_add(MemoryListener *listener, > > > > llsize = int128_sub(llend, int128_make64(iova)); > > > > + vhost_vdpa_iotlb_batch_begin_once(v); > > ret = vhost_vdpa_dma_map(v, iova, int128_get64(llsize), > > vaddr, section->readonly); > > if (ret) { > > @@ -221,6 +232,7 @@ static void vhost_vdpa_listener_region_del(MemoryListener *listener, > > > > llsize = int128_sub(llend, int128_make64(iova)); > > > > + vhost_vdpa_iotlb_batch_begin_once(v); > > ret = vhost_vdpa_dma_unmap(v, iova, int128_get64(llsize)); > > if (ret) { > > error_report("vhost_vdpa dma unmap error!"); > > @@ -234,7 +246,6 @@ static void vhost_vdpa_listener_region_del(MemoryListener *listener, > > * depends on the addnop(). > > */ > > static const MemoryListener vhost_vdpa_memory_listener = { > > - .begin = vhost_vdpa_listener_begin, > > .commit = vhost_vdpa_listener_commit, > > .region_add = vhost_vdpa_listener_region_add, > > .region_del = vhost_vdpa_listener_region_del, > > -- > > 2.27.0 > >