From nobody Sun Feb 8 22:34:46 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zoho.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1498734241576687.928595845863; Thu, 29 Jun 2017 04:04:01 -0700 (PDT) Received: from localhost ([::1]:38337 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dQXEq-00043a-CS for importer@patchew.org; Thu, 29 Jun 2017 07:03:56 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:51823) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dQX8k-00079z-Sn for qemu-devel@nongnu.org; Thu, 29 Jun 2017 06:57:39 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dQX8g-000895-VE for qemu-devel@nongnu.org; Thu, 29 Jun 2017 06:57:38 -0400 Received: from mx-v6.kamp.de ([2a02:248:0:51::16]:34692 helo=mx01.kamp.de) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dQX8g-00087O-N9 for qemu-devel@nongnu.org; Thu, 29 Jun 2017 06:57:34 -0400 Received: (qmail 9361 invoked by uid 89); 29 Jun 2017 10:57:33 -0000 Received: from [195.62.97.28] by client-16-kamp (envelope-from , uid 89) with qmail-scanner-2010/03/19-MF (clamdscan: 0.99.2/23517. avast: 1.2.2/17010300. spamassassin: 3.4.1. Clear:RC:1(195.62.97.28):. Processed in 0.342327 secs); 29 Jun 2017 10:57:33 -0000 Received: from smtp.kamp.de (HELO submission.kamp.de) ([195.62.97.28]) by mx01.kamp.de with ESMTPS (DHE-RSA-AES256-GCM-SHA384 encrypted); 29 Jun 2017 10:57:30 -0000 Received: (qmail 12784 invoked from network); 29 Jun 2017 10:57:15 -0000 Received: from lieven-pc.kamp-intra.net (HELO lieven-pc) (relay@kamp.de@::ffff:172.21.12.60) by submission.kamp.de with ESMTPS (DHE-RSA-AES256-GCM-SHA384 encrypted) ESMTPA; 29 Jun 2017 10:57:15 -0000 Received: by lieven-pc (Postfix, from userid 1000) id ACDF426C60; Thu, 29 Jun 2017 12:57:15 +0200 (CEST) X-GL_Whitelist: yes From: Peter Lieven To: qemu-block@nongnu.org Date: Thu, 29 Jun 2017 12:57:09 +0200 Message-Id: <1498733831-15254-7-git-send-email-pl@kamp.de> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1498733831-15254-1-git-send-email-pl@kamp.de> References: <1498733831-15254-1-git-send-email-pl@kamp.de> X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 2a02:248:0:51::16 Subject: [Qemu-devel] [PATCH V2 6/8] block/qcow2: optimize qcow2_co_pwritev_compressed 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, Peter Lieven , qemu-devel@nongnu.org, mreitz@redhat.com, den@openvz.org, lersek@redhat.com Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" if we specify exactly one iov of s->cluster_size bytes we can avoid the bounce buffer. Signed-off-by: Peter Lieven --- block/qcow2.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/block/qcow2.c b/block/qcow2.c index 39a8afc..0a7202a 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -2750,7 +2750,7 @@ qcow2_co_pwritev_compressed(BlockDriverState *bs, uin= t64_t offset, struct iovec iov; z_stream strm; int ret, out_len; - uint8_t *buf, *out_buf; + uint8_t *buf, *out_buf, *local_buf =3D NULL; uint64_t cluster_offset; =20 if (bytes =3D=3D 0) { @@ -2760,8 +2760,8 @@ qcow2_co_pwritev_compressed(BlockDriverState *bs, uin= t64_t offset, return bdrv_truncate(bs->file, cluster_offset, NULL); } =20 - buf =3D qemu_blockalign(bs, s->cluster_size); - if (bytes !=3D s->cluster_size) { + if (bytes !=3D s->cluster_size || qiov->niov !=3D 1) { + buf =3D local_buf =3D qemu_blockalign(bs, s->cluster_size); if (bytes > s->cluster_size || offset + bytes !=3D bs->total_sectors << BDRV_SECTOR_BITS) { @@ -2770,8 +2770,10 @@ qcow2_co_pwritev_compressed(BlockDriverState *bs, ui= nt64_t offset, } /* Zero-pad last write if image size is not cluster aligned */ memset(buf + bytes, 0, s->cluster_size - bytes); + qemu_iovec_to_buf(qiov, 0, buf, bytes); + } else { + buf =3D qiov->iov[0].iov_base; } - qemu_iovec_to_buf(qiov, 0, buf, bytes); =20 out_buf =3D g_malloc(s->cluster_size); =20 @@ -2839,7 +2841,7 @@ qcow2_co_pwritev_compressed(BlockDriverState *bs, uin= t64_t offset, success: ret =3D 0; fail: - qemu_vfree(buf); + qemu_vfree(local_buf); g_free(out_buf); return ret; } --=20 1.9.1