From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 90DA6C7618B for ; Thu, 25 Jul 2019 10:07:04 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 6BF4E218DA for ; Thu, 25 Jul 2019 10:07:04 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6BF4E218DA Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=virtuozzo.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:58334 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hqaeN-0000wn-La for qemu-devel@archiver.kernel.org; Thu, 25 Jul 2019 06:07:03 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:49320) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hqadO-0005WJ-9D for qemu-devel@nongnu.org; Thu, 25 Jul 2019 06:06:03 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hqadN-0006R5-65 for qemu-devel@nongnu.org; Thu, 25 Jul 2019 06:06:02 -0400 Received: from relay.sw.ru ([185.231.240.75]:45726) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hqadJ-0006O5-JR; Thu, 25 Jul 2019 06:05:57 -0400 Received: from [10.94.3.0] (helo=kvm.qa.sw.ru) by relay.sw.ru with esmtp (Exim 4.92) (envelope-from ) id 1hqadD-0001mQ-2y; Thu, 25 Jul 2019 13:05:51 +0300 From: Vladimir Sementsov-Ogievskiy To: qemu-devel@nongnu.org, qemu-block@nongnu.org Date: Thu, 25 Jul 2019 13:05:50 +0300 Message-Id: <20190725100550.33801-4-vsementsov@virtuozzo.com> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20190725100550.33801-1-vsementsov@virtuozzo.com> References: <20190725100550.33801-1-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 v3 3/3] nbd: improve CMD_CACHE: use BDRV_REQ_PREFETCH 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+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" 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 10faedcfc5..a2cf085f76 100644 --- a/nbd/server.c +++ b/nbd/server.c @@ -2104,12 +2104,15 @@ 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) @@ -2194,7 +2197,7 @@ 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) { @@ -2206,7 +2209,7 @@ 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); @@ -2214,7 +2217,7 @@ 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); } @@ -2233,6 +2236,28 @@ 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. */ @@ -2246,8 +2271,10 @@ 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: -- 2.18.0