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=-9.0 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 62B1AC04AB5 for ; Thu, 6 Jun 2019 13:51:13 +0000 (UTC) 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.kernel.org (Postfix) with ESMTPS id 3C8AE2070B for ; Thu, 6 Jun 2019 13:51:13 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3C8AE2070B 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 ([127.0.0.1]:60916 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hYsnQ-0007us-C3 for qemu-devel@archiver.kernel.org; Thu, 06 Jun 2019 09:51:12 -0400 Received: from eggs.gnu.org ([209.51.188.92]:44139) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hYsku-0006L9-B4 for qemu-devel@nongnu.org; Thu, 06 Jun 2019 09:48:37 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hYskg-0001j2-Qf for qemu-devel@nongnu.org; Thu, 06 Jun 2019 09:48:24 -0400 Received: from relay.sw.ru ([185.231.240.75]:45554) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hYskf-0001Hb-3j; Thu, 06 Jun 2019 09:48:22 -0400 Received: from [10.94.3.0] (helo=kvm.qa.sw.ru) by relay.sw.ru with esmtp (Exim 4.91) (envelope-from ) id 1hYska-00004z-0r; Thu, 06 Jun 2019 16:48:16 +0300 From: Vladimir Sementsov-Ogievskiy To: qemu-devel@nongnu.org, qemu-block@nongnu.org Date: Thu, 6 Jun 2019 16:48:12 +0300 Message-Id: <20190606134814.123689-2-vsementsov@virtuozzo.com> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20190606134814.123689-1-vsementsov@virtuozzo.com> References: <20190606134814.123689-1-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 1/3] block: implement blk_co_pcache 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: 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" Do effective copy-on-read request when we don't need data actually. It will be used for block-stream and NBD_CMD_CACHE. Signed-off-by: Vladimir Sementsov-Ogievskiy --- include/block/block.h | 8 +++++++- include/sysemu/block-backend.h | 7 +++++++ block/io.c | 18 ++++++++++++------ 3 files changed, 26 insertions(+), 7 deletions(-) diff --git a/include/block/block.h b/include/block/block.h index f9415ed740..4662f25513 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -88,8 +88,14 @@ typedef enum { * fallback. */ BDRV_REQ_NO_FALLBACK = 0x100, + /* + * BDRV_REQ_CACHE may be used only together with BDRV_REQ_COPY_ON_READ + * on read request and means that caller don't really need data to be + * written to qiov parameter which may be NULL. + */ + BDRV_REQ_CACHE = 0x200, /* Mask of valid flags */ - BDRV_REQ_MASK = 0x1ff, + BDRV_REQ_MASK = 0x3ff, } BdrvRequestFlags; typedef struct BlockSizes { diff --git a/include/sysemu/block-backend.h b/include/sysemu/block-backend.h index 733c4957eb..2bcecd1190 100644 --- a/include/sysemu/block-backend.h +++ b/include/sysemu/block-backend.h @@ -135,6 +135,13 @@ static inline int coroutine_fn blk_co_pread(BlockBackend *blk, int64_t offset, return blk_co_preadv(blk, offset, bytes, &qiov, flags); } +static inline int coroutine_fn blk_co_pcache(BlockBackend *blk, int64_t offset, + unsigned int bytes) +{ + return blk_co_preadv(blk, offset, bytes, NULL, + BDRV_REQ_COPY_ON_READ | BDRV_REQ_CACHE); +} + static inline int coroutine_fn blk_co_pwrite(BlockBackend *blk, int64_t offset, unsigned int bytes, void *buf, BdrvRequestFlags flags) diff --git a/block/io.c b/block/io.c index 9ba1bada36..9daf7332bd 100644 --- a/block/io.c +++ b/block/io.c @@ -1104,7 +1104,8 @@ bdrv_driver_pwritev_compressed(BlockDriverState *bs, uint64_t offset, } static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child, - int64_t offset, unsigned int bytes, QEMUIOVector *qiov) + int64_t offset, unsigned int bytes, QEMUIOVector *qiov, + int flags) { BlockDriverState *bs = child->bs; @@ -1215,9 +1216,11 @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child, goto err; } - qemu_iovec_from_buf(qiov, progress, bounce_buffer + skip_bytes, - pnum - skip_bytes); - } else { + if (!(flags & BDRV_REQ_CACHE)) { + qemu_iovec_from_buf(qiov, progress, bounce_buffer + skip_bytes, + pnum - skip_bytes); + } + } else if (!(flags & BDRV_REQ_CACHE)) { /* Read directly into the destination */ qemu_iovec_init(&local_qiov, qiov->niov); qemu_iovec_concat(&local_qiov, qiov, progress, pnum - skip_bytes); @@ -1268,7 +1271,8 @@ static int coroutine_fn bdrv_aligned_preadv(BdrvChild *child, * potential fallback support, if we ever implement any read flags * to pass through to drivers. For now, there aren't any * passthrough flags. */ - assert(!(flags & ~(BDRV_REQ_NO_SERIALISING | BDRV_REQ_COPY_ON_READ))); + assert(!(flags & ~(BDRV_REQ_NO_SERIALISING | BDRV_REQ_COPY_ON_READ | + BDRV_REQ_CACHE))); /* Handle Copy on Read and associated serialisation */ if (flags & BDRV_REQ_COPY_ON_READ) { @@ -1296,7 +1300,9 @@ static int coroutine_fn bdrv_aligned_preadv(BdrvChild *child, } if (!ret || pnum != bytes) { - ret = bdrv_co_do_copy_on_readv(child, offset, bytes, qiov); + ret = bdrv_co_do_copy_on_readv(child, offset, bytes, qiov, flags); + goto out; + } else if (flags & BDRV_REQ_CACHE) { goto out; } } -- 2.18.0