From nobody Tue Feb 10 06:04:41 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.zohomail.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 1521836760215416.31299754151587; Fri, 23 Mar 2018 13:26:00 -0700 (PDT) Received: from localhost ([::1]:39686 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ezTGB-0001h5-5U for importer@patchew.org; Fri, 23 Mar 2018 16:25:59 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:42268) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ezTEC-0000aq-7v for qemu-devel@nongnu.org; Fri, 23 Mar 2018 16:23:59 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ezTEB-0003oO-8P for qemu-devel@nongnu.org; Fri, 23 Mar 2018 16:23:56 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:40982 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1ezTEB-0003o9-3v for qemu-devel@nongnu.org; Fri, 23 Mar 2018 16:23:55 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id B7CE180AD20C; Fri, 23 Mar 2018 20:23:54 +0000 (UTC) Received: from dgilbert-t530.redhat.com (ovpn-117-129.ams2.redhat.com [10.36.117.129]) by smtp.corp.redhat.com (Postfix) with ESMTP id A35662023233; Fri, 23 Mar 2018 20:23:53 +0000 (UTC) From: "Dr. David Alan Gilbert (git)" To: qemu-devel@nongnu.org Date: Fri, 23 Mar 2018 20:23:42 +0000 Message-Id: <20180323202344.70640-4-dgilbert@redhat.com> In-Reply-To: <20180323202344.70640-1-dgilbert@redhat.com> References: <20180323202344.70640-1-dgilbert@redhat.com> X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Fri, 23 Mar 2018 20:23:54 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Fri, 23 Mar 2018 20:23:54 +0000 (UTC) for IP:'10.11.54.4' DOMAIN:'int-mx04.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'dgilbert@redhat.com' RCPT:'' X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 66.187.233.73 Subject: [Qemu-devel] [PULL 3/5] migration/block: limit the number of parallel I/O requests 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: pl@kamp.de, lidongchen@tencent.com, peterx@redhat.com, quintela@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" From: Peter Lieven the current implementation submits up to 512 I/O requests in parallel which is much to high especially for a background task. This patch adds a maximum limit of 16 I/O requests that can be submitted in parallel to avoid monopolizing the I/O device. Signed-off-by: Peter Lieven Message-Id: <1520507908-16743-5-git-send-email-pl@kamp.de> Reviewed-by: Juan Quintela Signed-off-by: Dr. David Alan Gilbert --- migration/block.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/migration/block.c b/migration/block.c index 5c03632257..03bbba61cb 100644 --- a/migration/block.c +++ b/migration/block.c @@ -37,6 +37,7 @@ #define MAX_IS_ALLOCATED_SEARCH (65536 * BDRV_SECTOR_SIZE) =20 #define MAX_IO_BUFFERS 512 +#define MAX_PARALLEL_IO 16 =20 //#define DEBUG_BLK_MIGRATION =20 @@ -775,6 +776,7 @@ static int block_save_iterate(QEMUFile *f, void *opaque) while ((block_mig_state.submitted + block_mig_state.read_done) * BLOCK_SIZE < qemu_file_get_rate_limit(f) && + block_mig_state.submitted < MAX_PARALLEL_IO && (block_mig_state.submitted + block_mig_state.read_done) < MAX_IO_BUFFERS) { blk_mig_unlock(); --=20 2.14.3