From owner-svn-src-head@FreeBSD.ORG Mon Aug 11 15:37:02 2014 Return-Path: Delivered-To: svn-src-head@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id A0CA3703 for ; Mon, 11 Aug 2014 15:37:02 +0000 (UTC) Received: from svn.freebsd.org (svn.freebsd.org [IPv6:2001:1900:2254:2068::e6a:0]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 76D3C2913 for ; Mon, 11 Aug 2014 15:37:02 +0000 (UTC) Received: from royger (uid 1332) (envelope-from royger@FreeBSD.org) id 2179 by svn.freebsd.org (DragonFly Mail Agent v0.9+); Mon, 11 Aug 2014 15:37:02 +0000 From: Roger Pau Monné Date: Mon, 11 Aug 2014 15:37:02 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r269814 - head/sys/dev/xen/blkfront X-SVN-Group: head MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Message-Id: <53e8e31e.2179.30c1c657@svn.freebsd.org> X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 11 Aug 2014 15:37:02 -0000 Author: royger Date: Mon Aug 11 15:37:02 2014 New Revision: 269814 URL: http://svnweb.freebsd.org/changeset/base/269814 Log: blkfront: add support for unmapped IO Using unmapped IO is really beneficial when running inside of a VM, since it avoids IPIs to other vCPUs in order to invalidate the mappings. This patch adds unmapped IO support to blkfront. The following tests results have been obtained when running on a Xen host without HAP: PVHVM 3165.84 real 6354.17 user 4483.32 sys PVHVM with unmapped IO 2099.46 real 4624.52 user 2967.38 sys This is because when running using shadow page tables TLB flushes and range invalidations are much more expensive, so using unmapped IO provides a very important performance boost. Sponsored by: Citrix Systems R&D Tested by: robak MFC after: 1 week PR: 191173 dev/xen/blkfront/blkfront.c: - Add and announce support for unmapped IO. Modified: head/sys/dev/xen/blkfront/blkfront.c Modified: head/sys/dev/xen/blkfront/blkfront.c ============================================================================== --- head/sys/dev/xen/blkfront/blkfront.c Mon Aug 11 15:06:07 2014 (r269813) +++ head/sys/dev/xen/blkfront/blkfront.c Mon Aug 11 15:37:02 2014 (r269814) @@ -272,8 +272,12 @@ xbd_queue_request(struct xbd_softc *sc, { int error; - error = bus_dmamap_load(sc->xbd_io_dmat, cm->cm_map, cm->cm_data, - cm->cm_datalen, xbd_queue_cb, cm, 0); + if (cm->cm_bp != NULL) + error = bus_dmamap_load_bio(sc->xbd_io_dmat, cm->cm_map, + cm->cm_bp, xbd_queue_cb, cm, 0); + else + error = bus_dmamap_load(sc->xbd_io_dmat, cm->cm_map, + cm->cm_data, cm->cm_datalen, xbd_queue_cb, cm, 0); if (error == EINPROGRESS) { /* * Maintain queuing order by freezing the queue. The next @@ -333,8 +337,6 @@ xbd_bio_command(struct xbd_softc *sc) } cm->cm_bp = bp; - cm->cm_data = bp->bio_data; - cm->cm_datalen = bp->bio_bcount; cm->cm_sector_number = (blkif_sector_t)bp->bio_pblkno; switch (bp->bio_cmd) { @@ -993,7 +995,7 @@ xbd_instance_create(struct xbd_softc *sc sc->xbd_disk->d_mediasize = sectors * sector_size; sc->xbd_disk->d_maxsize = sc->xbd_max_request_size; - sc->xbd_disk->d_flags = 0; + sc->xbd_disk->d_flags = DISKFLAG_UNMAPPED_BIO; if ((sc->xbd_flags & (XBDF_FLUSH|XBDF_BARRIER)) != 0) { sc->xbd_disk->d_flags |= DISKFLAG_CANFLUSHCACHE; device_printf(sc->xbd_dev,