From patchwork Tue Jun 18 15:42:02 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vladimir Sementsov-Ogievskiy X-Patchwork-Id: 11002213 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 1E8D71395 for ; Tue, 18 Jun 2019 16:42:36 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0D99E28B2A for ; Tue, 18 Jun 2019 16:42:36 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 01FED28B37; Tue, 18 Jun 2019 16:42:35 +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=-5.2 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 88E4028B2A for ; Tue, 18 Jun 2019 16:42:35 +0000 (UTC) Received: from localhost ([::1]:59738 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hdHBq-0004JD-Cl for patchwork-qemu-devel@patchwork.kernel.org; Tue, 18 Jun 2019 12:42:34 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:34217) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hdGFf-0007QK-M5 for qemu-devel@nongnu.org; Tue, 18 Jun 2019 11:42:29 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hdGFY-0005vL-US for qemu-devel@nongnu.org; Tue, 18 Jun 2019 11:42:24 -0400 Received: from relay.sw.ru ([185.231.240.75]:38504) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hdGFT-0005VZ-AZ; Tue, 18 Jun 2019 11:42:17 -0400 Received: from [10.94.3.0] (helo=kvm.qa.sw.ru) by relay.sw.ru with esmtp (Exim 4.92) (envelope-from ) id 1hdGFI-0002Sc-2i; Tue, 18 Jun 2019 18:42:04 +0300 From: Vladimir Sementsov-Ogievskiy To: qemu-devel@nongnu.org, qemu-block@nongnu.org Date: Tue, 18 Jun 2019 18:42:02 +0300 Message-Id: <20190618154202.89107-4-vsementsov@virtuozzo.com> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20190618154202.89107-1-vsementsov@virtuozzo.com> References: <20190618154202.89107-1-vsementsov@virtuozzo.com> X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 185.231.240.75 Subject: [Qemu-devel] [PATCH v2 3/3] nbd: improve CMD_CACHE: use blk_co_pcache 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: kwolf@redhat.com, fam@euphon.net, vsementsov@virtuozzo.com, mreitz@redhat.com, stefanha@redhat.com, den@openvz.org, jsnow@redhat.com Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP This helps to avoid extra io, allocations and memory copying. We assume here that CMD_CACHE is always used with copy-on-read, as otherwise it's a noop. Signed-off-by: Vladimir Sementsov-Ogievskiy --- nbd/server.c | 43 +++++++++++++++++++++++++++++++++++-------- 1 file changed, 35 insertions(+), 8 deletions(-) diff --git a/nbd/server.c b/nbd/server.c index aeca3893fe..6048257872 100644 --- a/nbd/server.c +++ b/nbd/server.c @@ -2101,12 +2101,15 @@ static int nbd_co_receive_request(NBDRequestData *req, NBDRequest *request, return -EINVAL; } - req->data = blk_try_blockalign(client->exp->blk, request->len); - if (req->data == NULL) { - error_setg(errp, "No memory"); - return -ENOMEM; + if (request->type != NBD_CMD_CACHE) { + req->data = blk_try_blockalign(client->exp->blk, request->len); + if (req->data == NULL) { + error_setg(errp, "No memory"); + return -ENOMEM; + } } } + if (request->type == NBD_CMD_WRITE) { if (nbd_read(client->ioc, req->data, request->len, "CMD_WRITE data", errp) < 0) @@ -2191,7 +2194,7 @@ static coroutine_fn int nbd_do_cmd_read(NBDClient *client, NBDRequest *request, int ret; NBDExport *exp = client->exp; - assert(request->type == NBD_CMD_READ || request->type == NBD_CMD_CACHE); + assert(request->type == NBD_CMD_READ); /* XXX: NBD Protocol only documents use of FUA with WRITE */ if (request->flags & NBD_CMD_FLAG_FUA) { @@ -2203,7 +2206,7 @@ static coroutine_fn int nbd_do_cmd_read(NBDClient *client, NBDRequest *request, } if (client->structured_reply && !(request->flags & NBD_CMD_FLAG_DF) && - request->len && request->type != NBD_CMD_CACHE) + request->len) { return nbd_co_send_sparse_read(client, request->handle, request->from, data, request->len, errp); @@ -2211,7 +2214,7 @@ static coroutine_fn int nbd_do_cmd_read(NBDClient *client, NBDRequest *request, ret = blk_pread(exp->blk, request->from + exp->dev_offset, data, request->len); - if (ret < 0 || request->type == NBD_CMD_CACHE) { + if (ret < 0) { return nbd_send_generic_reply(client, request->handle, ret, "reading from file failed", errp); } @@ -2230,6 +2233,28 @@ static coroutine_fn int nbd_do_cmd_read(NBDClient *client, NBDRequest *request, } } +/* + * nbd_do_cmd_cache + * + * Handle NBD_CMD_CACHE request. + * Return -errno if sending fails. Other errors are reported directly to the + * client as an error reply. + */ +static coroutine_fn int nbd_do_cmd_cache(NBDClient *client, NBDRequest *request, + Error **errp) +{ + int ret; + NBDExport *exp = client->exp; + + assert(request->type == NBD_CMD_CACHE); + + ret = blk_co_preadv(exp->blk, request->from + exp->dev_offset, request->len, + NULL, BDRV_REQ_COPY_ON_READ | BDRV_REQ_PREFETCH); + + return nbd_send_generic_reply(client, request->handle, ret, + "caching data failed", errp); +} + /* Handle NBD request. * Return -errno if sending fails. Other errors are reported directly to the * client as an error reply. */ @@ -2243,8 +2268,10 @@ static coroutine_fn int nbd_handle_request(NBDClient *client, char *msg; switch (request->type) { - case NBD_CMD_READ: case NBD_CMD_CACHE: + return nbd_do_cmd_cache(client, request, errp); + + case NBD_CMD_READ: return nbd_do_cmd_read(client, request, data, errp); case NBD_CMD_WRITE: