From nobody Tue Nov 11 00:22:14 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=virtuozzo.com ARC-Seal: i=1; a=rsa-sha256; t=1559829083; cv=none; d=zoho.com; s=zohoarc; b=FrVNQsdRizA85aH0M+ZOfJm0mwgYlsIlitR4iyj7ut+nyRY1l0N57sZ5Sai8jFYxqWaVCeDSXYGcTWxhw5U4Pkv1dqCOpSZBzn4ANVawHGMNgFelM1G6rTsXvApSqS/Qv+g+fAtDFyBFUu3KOlg1X0VPhyMIqM3xPQIl0n0UFvQ= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zoho.com; s=zohoarc; t=1559829083; h=Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:Message-ID:References:Sender:Subject:To:ARC-Authentication-Results; bh=dMvfxHVgnWjiZurddu16SdEdKnDq8Ce2V5/tmwGVwJ0=; b=EfMwNLboTUTzThxiqLY+kuV2n3AegIXvEgZuTYfIskNCCBcNlVxde64m4HU1gzuTWiFsLzjdTyaF0WyW+WI7iMRd/YJg6DzcdVqjFQL7CAZWInW0FK/kt2WuYe1rItjKShM2LHhTlRaG0g4o9WQgA4n/mqQ9hwjoJiGfV3/LbSg= ARC-Authentication-Results: i=1; mx.zoho.com; spf=pass (zoho.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail header.from= (p=none dis=none) header.from= Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1559829083952701.1444547215538; Thu, 6 Jun 2019 06:51:23 -0700 (PDT) Received: from localhost ([127.0.0.1]:60916 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hYsnY-0007us-Ps for importer@patchew.org; Thu, 06 Jun 2019 09:51:20 -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+importer=patchew.org@nongnu.org Sender: "Qemu-devel" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" 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 =3D 0x100, =20 + /* + * 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 =3D 0x200, /* Mask of valid flags */ - BDRV_REQ_MASK =3D 0x1ff, + BDRV_REQ_MASK =3D 0x3ff, } BdrvRequestFlags; =20 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(BlockBacke= nd *blk, int64_t offset, return blk_co_preadv(blk, offset, bytes, &qiov, flags); } =20 +static inline int coroutine_fn blk_co_pcache(BlockBackend *blk, int64_t of= fset, + 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 of= fset, 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, } =20 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 =3D child->bs; =20 @@ -1215,9 +1216,11 @@ static int coroutine_fn bdrv_co_do_copy_on_readv(Bdr= vChild *child, goto err; } =20 - 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_b= ytes, + 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_byt= es); @@ -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))); =20 /* 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, } =20 if (!ret || pnum !=3D bytes) { - ret =3D bdrv_co_do_copy_on_readv(child, offset, bytes, qiov); + ret =3D bdrv_co_do_copy_on_readv(child, offset, bytes, qiov, f= lags); + goto out; + } else if (flags & BDRV_REQ_CACHE) { goto out; } } --=20 2.18.0