From patchwork Thu Jan 10 13:49:17 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anthony PERARD X-Patchwork-Id: 10755951 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 1971714DE for ; Thu, 10 Jan 2019 14:30:50 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 046D629967 for ; Thu, 10 Jan 2019 14:30:50 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 02E5329981; Thu, 10 Jan 2019 14:30:49 +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=-2.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 950D7299AB for ; Thu, 10 Jan 2019 14:30:49 +0000 (UTC) Received: from localhost ([127.0.0.1]:35839 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ghbM8-0004QO-Rc for patchwork-qemu-devel@patchwork.kernel.org; Thu, 10 Jan 2019 09:30:48 -0500 Received: from eggs.gnu.org ([209.51.188.92]:58546) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ghb5L-0006cH-0m for qemu-devel@nongnu.org; Thu, 10 Jan 2019 09:13:27 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gharK-0002Km-7G for qemu-devel@nongnu.org; Thu, 10 Jan 2019 08:58:58 -0500 Received: from smtp03.citrix.com ([162.221.156.55]:12008) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gharJ-0001xV-Vr for qemu-devel@nongnu.org; Thu, 10 Jan 2019 08:58:58 -0500 X-IronPort-AV: E=Sophos;i="5.56,461,1539648000"; d="scan'208";a="75263660" From: Anthony PERARD To: Date: Thu, 10 Jan 2019 13:49:17 +0000 Message-ID: <20190110134917.16425-26-anthony.perard@citrix.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190110134917.16425-1-anthony.perard@citrix.com> References: <20190110134917.16425-1-anthony.perard@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] [PULL 25/25] xen-block: avoid repeated memory allocation 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 , xen-devel@lists.xenproject.org, Paul Durrant , Tim Smith Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP From: Tim Smith The xen-block dataplane currently allocates memory to hold the data for each request as that request is used, and frees it afterwards. Because it requires page-aligned blocks, this interacts poorly with non-page- aligned allocations and balloons the heap. Instead, allocate the maximum possible buffer size required for the protocol, which is BLKIF_MAX_SEGMENTS_PER_REQUEST (currently 11) pages when the request structure is created, and keep that buffer until it is destroyed. Since the requests are re-used via a free list, this should actually improve memory usage. Signed-off-by: Tim Smith Re-based and commit comment adjusted. Signed-off-by: Paul Durrant Acked-by: Anthony PERARD Signed-off-by: Anthony PERARD --- hw/block/dataplane/xen-block.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/hw/block/dataplane/xen-block.c b/hw/block/dataplane/xen-block.c index 35bfccfba7..d0d8905a33 100644 --- a/hw/block/dataplane/xen-block.c +++ b/hw/block/dataplane/xen-block.c @@ -70,7 +70,6 @@ static void reset_request(XenBlockRequest *request) memset(&request->req, 0, sizeof(request->req)); request->status = 0; request->start = 0; - request->buf = NULL; request->size = 0; request->presync = 0; @@ -95,6 +94,14 @@ static XenBlockRequest *xen_block_start_request(XenBlockDataPlane *dataplane) /* allocate new struct */ request = g_malloc0(sizeof(*request)); request->dataplane = dataplane; + /* + * We cannot need more pages per requests than this, and since we + * re-use requests, allocate the memory once here. It will be freed + * xen_block_dataplane_destroy() when the request list is freed. + */ + request->buf = qemu_memalign(XC_PAGE_SIZE, + BLKIF_MAX_SEGMENTS_PER_REQUEST * + XC_PAGE_SIZE); dataplane->requests_total++; qemu_iovec_init(&request->v, 1); } else { @@ -272,14 +279,12 @@ static void xen_block_complete_aio(void *opaque, int ret) if (ret == 0) { xen_block_copy_request(request); } - qemu_vfree(request->buf); break; case BLKIF_OP_WRITE: case BLKIF_OP_FLUSH_DISKCACHE: if (!request->req.nr_segments) { break; } - qemu_vfree(request->buf); break; default: break; @@ -360,12 +365,10 @@ static int xen_block_do_aio(XenBlockRequest *request) { XenBlockDataPlane *dataplane = request->dataplane; - request->buf = qemu_memalign(XC_PAGE_SIZE, request->size); if (request->req.nr_segments && (request->req.operation == BLKIF_OP_WRITE || request->req.operation == BLKIF_OP_FLUSH_DISKCACHE) && xen_block_copy_request(request)) { - qemu_vfree(request->buf); goto err; } @@ -665,6 +668,7 @@ void xen_block_dataplane_destroy(XenBlockDataPlane *dataplane) request = QLIST_FIRST(&dataplane->freelist); QLIST_REMOVE(request, list); qemu_iovec_destroy(&request->v); + qemu_vfree(request->buf); g_free(request); }