From patchwork Fri May 4 13:55:33 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paul Durrant X-Patchwork-Id: 10380551 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id D356760353 for ; Fri, 4 May 2018 13:57:26 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B19F829456 for ; Fri, 4 May 2018 13:57:26 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id A63352945E; Fri, 4 May 2018 13:57:26 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00, MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 02EDA29453 for ; Fri, 4 May 2018 13:57:24 +0000 (UTC) Received: from localhost ([::1]:34530 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fEbD9-0006Dj-KW for patchwork-qemu-devel@patchwork.kernel.org; Fri, 04 May 2018 09:57:23 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:50530) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fEbBo-00050K-I2 for qemu-devel@nongnu.org; Fri, 04 May 2018 09:56:01 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fEbBn-0003ZD-Am for qemu-devel@nongnu.org; Fri, 04 May 2018 09:56:00 -0400 Received: from smtp03.citrix.com ([162.221.156.55]:24303) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fEbBj-0003QE-JJ; Fri, 04 May 2018 09:55:55 -0400 X-IronPort-AV: E=Sophos;i="5.49,362,1520899200"; d="scan'208";a="53691045" From: Paul Durrant To: , , Date: Fri, 4 May 2018 14:55:33 +0100 Message-ID: <1525442134-20488-8-git-send-email-paul.durrant@citrix.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1525442134-20488-1-git-send-email-paul.durrant@citrix.com> References: <1525442134-20488-1-git-send-email-paul.durrant@citrix.com> MIME-Version: 1.0 X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 162.221.156.55 Subject: [Qemu-devel] [PATCH v2 7/8] xen_disk: use a single entry iovec X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Anthony Perard , Kevin Wolf , Paul Durrant , Stefano Stabellini , Max Reitz Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP Since xen_disk now always copies data to and from a guest there is no need to maintain a vector entry corresponding to every page of a request. This means there is less per-request state to maintain so the ioreq structure can shrink significantly. Signed-off-by: Paul Durrant --- Cc: Stefano Stabellini Cc: Anthony Perard Cc: Kevin Wolf Cc: Max Reitz v2: - Re-based --- hw/block/xen_disk.c | 71 ++++++++++++++--------------------------------------- 1 file changed, 18 insertions(+), 53 deletions(-) diff --git a/hw/block/xen_disk.c b/hw/block/xen_disk.c index 28be8b6..230961f 100644 --- a/hw/block/xen_disk.c +++ b/hw/block/xen_disk.c @@ -46,13 +46,10 @@ struct ioreq { /* parsed request */ off_t start; QEMUIOVector v; + void *buf; + size_t size; int presync; - /* grant mapping */ - uint32_t refs[BLKIF_MAX_SEGMENTS_PER_REQUEST]; - void *page[BLKIF_MAX_SEGMENTS_PER_REQUEST]; - void *pages; - /* aio status */ int aio_inflight; int aio_errors; @@ -110,12 +107,10 @@ static void ioreq_reset(struct ioreq *ioreq) memset(&ioreq->req, 0, sizeof(ioreq->req)); ioreq->status = 0; ioreq->start = 0; + ioreq->buf = NULL; + ioreq->size = 0; ioreq->presync = 0; - memset(ioreq->refs, 0, sizeof(ioreq->refs)); - memset(ioreq->page, 0, sizeof(ioreq->page)); - ioreq->pages = NULL; - ioreq->aio_inflight = 0; ioreq->aio_errors = 0; @@ -138,7 +133,7 @@ static struct ioreq *ioreq_start(struct XenBlkDev *blkdev) ioreq = g_malloc0(sizeof(*ioreq)); ioreq->blkdev = blkdev; blkdev->requests_total++; - qemu_iovec_init(&ioreq->v, BLKIF_MAX_SEGMENTS_PER_REQUEST); + qemu_iovec_init(&ioreq->v, 1); } else { /* get one from freelist */ ioreq = QLIST_FIRST(&blkdev->freelist); @@ -183,7 +178,6 @@ static void ioreq_release(struct ioreq *ioreq, bool finish) static int ioreq_parse(struct ioreq *ioreq) { struct XenBlkDev *blkdev = ioreq->blkdev; - uintptr_t mem; size_t len; int i; @@ -230,13 +224,10 @@ static int ioreq_parse(struct ioreq *ioreq) goto err; } - ioreq->refs[i] = ioreq->req.seg[i].gref; - - mem = ioreq->req.seg[i].first_sect * blkdev->file_blk; len = (ioreq->req.seg[i].last_sect - ioreq->req.seg[i].first_sect + 1) * blkdev->file_blk; - qemu_iovec_add(&ioreq->v, (void*)mem, len); + ioreq->size += len; } - if (ioreq->start + ioreq->v.size > blkdev->file_size) { + if (ioreq->start + ioreq->size > blkdev->file_size) { xen_pv_printf(&blkdev->xendev, 0, "error: access beyond end of file\n"); goto err; } @@ -247,35 +238,6 @@ err: return -1; } -static void ioreq_free_copy_buffers(struct ioreq *ioreq) -{ - int i; - - for (i = 0; i < ioreq->v.niov; i++) { - ioreq->page[i] = NULL; - } - - qemu_vfree(ioreq->pages); -} - -static int ioreq_init_copy_buffers(struct ioreq *ioreq) -{ - int i; - - if (ioreq->v.niov == 0) { - return 0; - } - - ioreq->pages = qemu_memalign(XC_PAGE_SIZE, ioreq->v.niov * XC_PAGE_SIZE); - - for (i = 0; i < ioreq->v.niov; i++) { - ioreq->page[i] = ioreq->pages + i * XC_PAGE_SIZE; - ioreq->v.iov[i].iov_base = ioreq->page[i]; - } - - return 0; -} - static int ioreq_grant_copy(struct ioreq *ioreq) { struct XenBlkDev *blkdev = ioreq->blkdev; @@ -284,6 +246,7 @@ static int ioreq_grant_copy(struct ioreq *ioreq) int i, count, rc; int64_t file_blk = ioreq->blkdev->file_blk; bool to_domain = (ioreq->req.operation == BLKIF_OP_READ); + void *virt = ioreq->buf; if (ioreq->v.niov == 0) { return 0; @@ -293,16 +256,17 @@ static int ioreq_grant_copy(struct ioreq *ioreq) for (i = 0; i < count; i++) { if (to_domain) { - segs[i].dest.foreign.ref = ioreq->refs[i]; + segs[i].dest.foreign.ref = ioreq->req.seg[i].gref; segs[i].dest.foreign.offset = ioreq->req.seg[i].first_sect * file_blk; - segs[i].source.virt = ioreq->v.iov[i].iov_base; + segs[i].source.virt = virt; } else { - segs[i].source.foreign.ref = ioreq->refs[i]; + segs[i].source.foreign.ref = ioreq->req.seg[i].gref; segs[i].source.foreign.offset = ioreq->req.seg[i].first_sect * file_blk; - segs[i].dest.virt = ioreq->v.iov[i].iov_base; + segs[i].dest.virt = virt; } segs[i].len = (ioreq->req.seg[i].last_sect - ioreq->req.seg[i].first_sect + 1) * file_blk; + virt += segs[i].len; } rc = xen_be_copy_grant_refs(xendev, to_domain, segs, count); @@ -314,6 +278,7 @@ static int ioreq_grant_copy(struct ioreq *ioreq) return -1; } + qemu_iovec_add(&ioreq->v, ioreq->buf, ioreq->size); return rc; } @@ -348,14 +313,14 @@ static void qemu_aio_complete(void *opaque, int ret) if (ret == 0) { ioreq_grant_copy(ioreq); } - ioreq_free_copy_buffers(ioreq); + qemu_vfree(ioreq->buf); break; case BLKIF_OP_WRITE: case BLKIF_OP_FLUSH_DISKCACHE: if (!ioreq->req.nr_segments) { break; } - ioreq_free_copy_buffers(ioreq); + qemu_vfree(ioreq->buf); break; default: break; @@ -423,12 +388,12 @@ static int ioreq_runio_qemu_aio(struct ioreq *ioreq) { struct XenBlkDev *blkdev = ioreq->blkdev; - ioreq_init_copy_buffers(ioreq); + ioreq->buf = qemu_memalign(XC_PAGE_SIZE, ioreq->size); if (ioreq->req.nr_segments && (ioreq->req.operation == BLKIF_OP_WRITE || ioreq->req.operation == BLKIF_OP_FLUSH_DISKCACHE) && ioreq_grant_copy(ioreq)) { - ioreq_free_copy_buffers(ioreq); + qemu_vfree(ioreq->buf); goto err; }