From patchwork Wed Jun 17 13:14:56 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Igor Mammedov X-Patchwork-Id: 6625871 Return-Path: X-Original-To: patchwork-kvm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 15EFD9F1C1 for ; Wed, 17 Jun 2015 13:18:37 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 6D3BA2055A for ; Wed, 17 Jun 2015 13:18:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EDDCD20885 for ; Wed, 17 Jun 2015 13:18:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756857AbbFQNSP (ORCPT ); Wed, 17 Jun 2015 09:18:15 -0400 Received: from mx1.redhat.com ([209.132.183.28]:45258 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932312AbbFQNPJ (ORCPT ); Wed, 17 Jun 2015 09:15:09 -0400 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) by mx1.redhat.com (Postfix) with ESMTPS id 43E14C463C; Wed, 17 Jun 2015 13:15:09 +0000 (UTC) Received: from dell-r430-03.lab.eng.brq.redhat.com (dell-r430-03.lab.eng.brq.redhat.com [10.34.112.60]) by int-mx11.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id t5HDF1Bp030705; Wed, 17 Jun 2015 09:15:07 -0400 From: Igor Mammedov To: linux-kernel@vger.kernel.org Cc: mst@redhat.com, kvm@vger.kernel.org, pbonzini@redhat.com, andrey@xdel.ru, digitaleric@google.com Subject: [PATCH v2 3/6] vhost: add per VQ memory region caching Date: Wed, 17 Jun 2015 15:14:56 +0200 Message-Id: <1434546899-5296-4-git-send-email-imammedo@redhat.com> In-Reply-To: <1434546899-5296-1-git-send-email-imammedo@redhat.com> References: <1434546899-5296-1-git-send-email-imammedo@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.24 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Spam-Status: No, score=-7.5 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP that brings down translate_desc() cost to around 210ns if accessed descriptors are from the same memory region. Signed-off-by: Igor Mammedov --- that's what netperf/iperf workloads were during testing. --- drivers/vhost/vhost.c | 16 +++++++++++++--- drivers/vhost/vhost.h | 1 + 2 files changed, 14 insertions(+), 3 deletions(-) diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index 99931a0..5c39a1e 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -200,6 +200,7 @@ static void vhost_vq_reset(struct vhost_dev *dev, vq->call = NULL; vq->log_ctx = NULL; vq->memory = NULL; + vq->cached_reg = 0; } static int vhost_worker(void *data) @@ -649,6 +650,7 @@ static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m) for (i = 0; i < d->nvqs; ++i) { mutex_lock(&d->vqs[i]->mutex); d->vqs[i]->memory = newmem; + d->vqs[i]->cached_reg = 0; mutex_unlock(&d->vqs[i]->mutex); } kvfree(oldmem); @@ -936,11 +938,17 @@ done: EXPORT_SYMBOL_GPL(vhost_dev_ioctl); static const struct vhost_memory_region *find_region(struct vhost_memory *mem, - __u64 addr, __u32 len) + __u64 addr, __u32 len, + int *cached_reg) { const struct vhost_memory_region *reg; int start = 0, end = mem->nregions; + reg = mem->regions + *cached_reg; + if (likely(addr >= reg->guest_phys_addr && + reg->guest_phys_addr + reg->memory_size > addr)) + return reg; + while (start < end) { int slot = start + (end - start) / 2; reg = mem->regions + slot; @@ -952,8 +960,10 @@ static const struct vhost_memory_region *find_region(struct vhost_memory *mem, reg = mem->regions + start; if (addr >= reg->guest_phys_addr && - reg->guest_phys_addr + reg->memory_size > addr) + reg->guest_phys_addr + reg->memory_size > addr) { + *cached_reg = start; return reg; + } return NULL; } @@ -1107,7 +1117,7 @@ static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len, ret = -ENOBUFS; break; } - reg = find_region(mem, addr, len); + reg = find_region(mem, addr, len, &vq->cached_reg); if (unlikely(!reg)) { ret = -EFAULT; break; diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h index 8c1c792..68bd00f 100644 --- a/drivers/vhost/vhost.h +++ b/drivers/vhost/vhost.h @@ -106,6 +106,7 @@ struct vhost_virtqueue { /* Log write descriptors */ void __user *log_base; struct vhost_log *log; + int cached_reg; }; struct vhost_dev {