From patchwork Thu Mar 25 15:07:28 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kurz X-Patchwork-Id: 12164267 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=-13.8 required=3.0 tests=BAYES_00, 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 BF21BC433DB for ; Thu, 25 Mar 2021 15:08:57 +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 F3CA660C3E for ; Thu, 25 Mar 2021 15:08:56 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F3CA660C3E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kaod.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:33458 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lPRbT-0006bM-VS for qemu-devel@archiver.kernel.org; Thu, 25 Mar 2021 11:08:56 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:34978) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lPRaV-0004gg-2t for qemu-devel@nongnu.org; Thu, 25 Mar 2021 11:07:55 -0400 Received: from us-smtp-delivery-44.mimecast.com ([205.139.111.44]:48246) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lPRaT-0007dw-6f for qemu-devel@nongnu.org; Thu, 25 Mar 2021 11:07:54 -0400 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-40-mtMwooD0PWSw7_M90LqH7w-1; Thu, 25 Mar 2021 11:07:50 -0400 X-MC-Unique: mtMwooD0PWSw7_M90LqH7w-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id A874A1005D57; Thu, 25 Mar 2021 15:07:48 +0000 (UTC) Received: from bahia.redhat.com (ovpn-113-20.ams2.redhat.com [10.36.113.20]) by smtp.corp.redhat.com (Postfix) with ESMTP id ADFAA5C649; Thu, 25 Mar 2021 15:07:46 +0000 (UTC) From: Greg Kurz To: qemu-devel@nongnu.org Subject: [RFC 1/8] memory: Allow eventfd add/del without starting a transaction Date: Thu, 25 Mar 2021 16:07:28 +0100 Message-Id: <20210325150735.1098387-2-groug@kaod.org> In-Reply-To: <20210325150735.1098387-1-groug@kaod.org> References: <20210325150735.1098387-1-groug@kaod.org> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=groug@kaod.org X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: kaod.org Received-SPF: softfail client-ip=205.139.111.44; envelope-from=groug@kaod.org; helo=us-smtp-delivery-44.mimecast.com X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_LOW=-0.7, SPF_HELO_NONE=0.001, SPF_SOFTFAIL=0.665 autolearn=no 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: Fam Zheng , Kevin Wolf , qemu-block@nongnu.org, "Michael S. Tsirkin" , Greg Kurz , Max Reitz , Stefan Hajnoczi , Paolo Bonzini , David Gibson Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Each addition or deletion of an eventfd happens in its own MR transaction. This doesn't scale well with multiqueue devices that do 1:1 queue:vCPU mapping (e.g. virtio-scsi-pci or virtio-blk-pci) : these devices typically create at least one eventfd per queue and memory_region_transaction_commit(), which is called during commit, also loops on eventfds, resulting in a quadratic time complexity. This calls for batching : a device should be able to add or delete its eventfds in a single transaction. Prepare ground for this by introducing extended versions of memory_region_add_eventfd() and memory_region_del_eventfd() that take an extra bool argument to control if a transaction should be started or not. No behavior change at this point. Signed-off-by: Greg Kurz --- include/exec/memory.h | 48 ++++++++++++++++++++++++++++++++----------- softmmu/memory.c | 42 ++++++++++++++++++++++--------------- 2 files changed, 62 insertions(+), 28 deletions(-) diff --git a/include/exec/memory.h b/include/exec/memory.h index 5728a681b27d..98ed552e001c 100644 --- a/include/exec/memory.h +++ b/include/exec/memory.h @@ -1848,13 +1848,25 @@ void memory_region_clear_flush_coalesced(MemoryRegion *mr); * @match_data: whether to match against @data, instead of just @addr * @data: the data to match against the guest write * @e: event notifier to be triggered when @addr, @size, and @data all match. + * @transaction: whether to start a transaction for the change **/ -void memory_region_add_eventfd(MemoryRegion *mr, - hwaddr addr, - unsigned size, - bool match_data, - uint64_t data, - EventNotifier *e); +void memory_region_add_eventfd_full(MemoryRegion *mr, + hwaddr addr, + unsigned size, + bool match_data, + uint64_t data, + EventNotifier *e, + bool transaction); + +static inline void memory_region_add_eventfd(MemoryRegion *mr, + hwaddr addr, + unsigned size, + bool match_data, + uint64_t data, + EventNotifier *e) +{ + memory_region_add_eventfd_full(mr, addr, size, match_data, data, e, true); +} /** * memory_region_del_eventfd: Cancel an eventfd. @@ -1868,13 +1880,25 @@ void memory_region_add_eventfd(MemoryRegion *mr, * @match_data: whether to match against @data, instead of just @addr * @data: the data to match against the guest write * @e: event notifier to be triggered when @addr, @size, and @data all match. + * @transaction: whether to start a transaction for the change */ -void memory_region_del_eventfd(MemoryRegion *mr, - hwaddr addr, - unsigned size, - bool match_data, - uint64_t data, - EventNotifier *e); +void memory_region_del_eventfd_full(MemoryRegion *mr, + hwaddr addr, + unsigned size, + bool match_data, + uint64_t data, + EventNotifier *e, + bool transaction); + +static inline void memory_region_del_eventfd(MemoryRegion *mr, + hwaddr addr, + unsigned size, + bool match_data, + uint64_t data, + EventNotifier *e) +{ + memory_region_del_eventfd_full(mr, addr, size, match_data, data, e, true); +} /** * memory_region_add_subregion: Add a subregion to a container. diff --git a/softmmu/memory.c b/softmmu/memory.c index d4493ef9e430..1b1942d521cc 100644 --- a/softmmu/memory.c +++ b/softmmu/memory.c @@ -2341,12 +2341,13 @@ void memory_region_clear_flush_coalesced(MemoryRegion *mr) static bool userspace_eventfd_warning; -void memory_region_add_eventfd(MemoryRegion *mr, - hwaddr addr, - unsigned size, - bool match_data, - uint64_t data, - EventNotifier *e) +void memory_region_add_eventfd_full(MemoryRegion *mr, + hwaddr addr, + unsigned size, + bool match_data, + uint64_t data, + EventNotifier *e, + bool transaction) { MemoryRegionIoeventfd mrfd = { .addr.start = int128_make64(addr), @@ -2367,7 +2368,9 @@ void memory_region_add_eventfd(MemoryRegion *mr, if (size) { adjust_endianness(mr, &mrfd.data, size_memop(size) | MO_TE); } - memory_region_transaction_begin(); + if (transaction) { + memory_region_transaction_begin(); + } for (i = 0; i < mr->ioeventfd_nb; ++i) { if (memory_region_ioeventfd_before(&mrfd, &mr->ioeventfds[i])) { break; @@ -2380,15 +2383,18 @@ void memory_region_add_eventfd(MemoryRegion *mr, sizeof(*mr->ioeventfds) * (mr->ioeventfd_nb-1 - i)); mr->ioeventfds[i] = mrfd; ioeventfd_update_pending |= mr->enabled; - memory_region_transaction_commit(); + if (transaction) { + memory_region_transaction_commit(); + } } -void memory_region_del_eventfd(MemoryRegion *mr, - hwaddr addr, - unsigned size, - bool match_data, - uint64_t data, - EventNotifier *e) +void memory_region_del_eventfd_full(MemoryRegion *mr, + hwaddr addr, + unsigned size, + bool match_data, + uint64_t data, + EventNotifier *e, + bool transaction) { MemoryRegionIoeventfd mrfd = { .addr.start = int128_make64(addr), @@ -2402,7 +2408,9 @@ void memory_region_del_eventfd(MemoryRegion *mr, if (size) { adjust_endianness(mr, &mrfd.data, size_memop(size) | MO_TE); } - memory_region_transaction_begin(); + if (transaction) { + memory_region_transaction_begin(); + } for (i = 0; i < mr->ioeventfd_nb; ++i) { if (memory_region_ioeventfd_equal(&mrfd, &mr->ioeventfds[i])) { break; @@ -2415,7 +2423,9 @@ void memory_region_del_eventfd(MemoryRegion *mr, mr->ioeventfds = g_realloc(mr->ioeventfds, sizeof(*mr->ioeventfds)*mr->ioeventfd_nb + 1); ioeventfd_update_pending |= mr->enabled; - memory_region_transaction_commit(); + if (transaction) { + memory_region_transaction_commit(); + } } static void memory_region_update_container_subregions(MemoryRegion *subregion)