From patchwork Tue Sep 1 12:51:29 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Lieven X-Patchwork-Id: 1354955 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=kamp.de 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 ozlabs.org (Postfix) with ESMTPS id 4Bgn6b4vNtz9sVT for ; Tue, 1 Sep 2020 22:52:55 +1000 (AEST) Received: from localhost ([::1]:34122 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kD5mP-0001QC-Ix for incoming@patchwork.ozlabs.org; Tue, 01 Sep 2020 08:52:53 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:35212) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kD5lK-0008Mo-Ov for qemu-devel@nongnu.org; Tue, 01 Sep 2020 08:51:46 -0400 Received: from kerio.kamp.de ([195.62.97.192]:60820) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kD5lI-00026E-Hy for qemu-devel@nongnu.org; Tue, 01 Sep 2020 08:51:46 -0400 X-Footer: a2FtcC5kZQ== Received: from submission.kamp.de ([195.62.97.28]) by kerio.kamp.de with ESMTPS (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256 bits)) for qemu-devel@nongnu.org; Tue, 1 Sep 2020 14:51:27 +0200 Received: (qmail 58193 invoked from network); 1 Sep 2020 12:51:34 -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; 1 Sep 2020 12:51:34 -0000 Received: by lieven-pc (Postfix, from userid 1060) id 3D33413D866; Tue, 1 Sep 2020 14:51:34 +0200 (CEST) From: Peter Lieven To: qemu-devel@nongnu.org Subject: [PATCH] qemu-img: avoid unaligned read requests during convert Date: Tue, 1 Sep 2020 14:51:29 +0200 Message-Id: <20200901125129.6398-1-pl@kamp.de> X-Mailer: git-send-email 2.17.1 Received-SPF: pass client-ip=195.62.97.192; envelope-from=pl@kamp.de; helo=kerio.kamp.de X-detected-operating-system: by eggs.gnu.org: First seen = 2020/09/01 08:51:35 X-ACL-Warn: Detected OS = Linux 3.11 and newer [fuzzy] X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action 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, Peter Lieven , qemu-block@nongnu.org, mreitz@redhat.com Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" in case of large continous areas that share the same allocation status it happens that the value of s->sector_next_status is unaligned to the cluster size or even request alignment of the source. Avoid this by stripping down the s->sector_next_status position to cluster boundaries. Signed-off-by: Peter Lieven --- qemu-img.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/qemu-img.c b/qemu-img.c index 5308773811..ed17238c36 100644 --- a/qemu-img.c +++ b/qemu-img.c @@ -1665,6 +1665,7 @@ enum ImgConvertBlockStatus { typedef struct ImgConvertState { BlockBackend **src; int64_t *src_sectors; + int *src_alignment; int src_num; int64_t total_sectors; int64_t allocated_sectors; @@ -1731,6 +1732,7 @@ static int convert_iteration_sectors(ImgConvertState *s, int64_t sector_num) if (s->sector_next_status <= sector_num) { uint64_t offset = (sector_num - src_cur_offset) * BDRV_SECTOR_SIZE; int64_t count; + int tail; do { count = n * BDRV_SECTOR_SIZE; @@ -1769,6 +1771,16 @@ static int convert_iteration_sectors(ImgConvertState *s, int64_t sector_num) n = DIV_ROUND_UP(count, BDRV_SECTOR_SIZE); + /* + * Avoid that s->sector_next_status becomes unaligned to the source + * request alignment and/or cluster size to avoid unnecessary read + * cycles. + */ + tail = (sector_num - src_cur_offset + n) % s->src_alignment[src_cur]; + if (n > tail) { + n -= tail; + } + if (ret & BDRV_BLOCK_ZERO) { s->status = post_backing_zero ? BLK_BACKING_FILE : BLK_ZERO; } else if (ret & BDRV_BLOCK_DATA) { @@ -2407,8 +2419,10 @@ static int img_convert(int argc, char **argv) s.src = g_new0(BlockBackend *, s.src_num); s.src_sectors = g_new(int64_t, s.src_num); + s.src_alignment = g_new(int, s.src_num); for (bs_i = 0; bs_i < s.src_num; bs_i++) { + BlockDriverState *src_bs; s.src[bs_i] = img_open(image_opts, argv[optind + bs_i], fmt, src_flags, src_writethrough, s.quiet, force_share); @@ -2423,6 +2437,13 @@ static int img_convert(int argc, char **argv) ret = -1; goto out; } + src_bs = blk_bs(s.src[bs_i]); + s.src_alignment[bs_i] = DIV_ROUND_UP(src_bs->bl.request_alignment, + BDRV_SECTOR_SIZE); + if (!bdrv_get_info(src_bs, &bdi)) { + s.src_alignment[bs_i] = MAX(s.src_alignment[bs_i], + bdi.cluster_size / BDRV_SECTOR_SIZE); + } s.total_sectors += s.src_sectors[bs_i]; } @@ -2704,6 +2725,7 @@ out: g_free(s.src); } g_free(s.src_sectors); + g_free(s.src_alignment); fail_getopt: g_free(options);