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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 4A556C3A589 for ; Thu, 15 Aug 2019 16:43:41 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 1BB0120578 for ; Thu, 15 Aug 2019 16:43:41 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1BB0120578 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:44364 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1hyIqi-0002h3-31 for qemu-devel@archiver.kernel.org; Thu, 15 Aug 2019 12:43:40 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:47415) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1hyIjk-0002h9-Ca for qemu-devel@nongnu.org; Thu, 15 Aug 2019 12:36:32 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hyIjf-0003G0-58 for qemu-devel@nongnu.org; Thu, 15 Aug 2019 12:36:28 -0400 Received: from mx1.redhat.com ([209.132.183.28]:51526) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hyIje-0003Fg-UG for qemu-devel@nongnu.org; Thu, 15 Aug 2019 12:36:23 -0400 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 41BFF8666C; Thu, 15 Aug 2019 16:36:22 +0000 (UTC) Received: from dgilbert-t580.localhost (ovpn-117-19.ams2.redhat.com [10.36.117.19]) by smtp.corp.redhat.com (Postfix) with ESMTP id 007F23737; Thu, 15 Aug 2019 16:36:18 +0000 (UTC) From: "Dr. David Alan Gilbert (git)" To: qemu-devel@nongnu.org Date: Thu, 15 Aug 2019 17:34:51 +0100 Message-Id: <20190815163504.18937-21-dgilbert@redhat.com> In-Reply-To: <20190815163504.18937-1-dgilbert@redhat.com> References: <20190815163504.18937-1-dgilbert@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.26]); Thu, 15 Aug 2019 16:36:22 +0000 (UTC) Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PULL 20/33] migration/postcopy: simplify calculation of run_start and fixup_start_addr 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: quintela@redhat.com, yury-kotov@yandex-team.ru, richardw.yang@linux.intel.com, marcandre.lureau@redhat.com, ivanren@tencent.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" From: Wei Yang The purpose of the calculation is to find a HostPage which is partially dirty. * fixup_start_addr points to the start of the HostPage to discard * run_start points to the next HostPage to check While in the middle stage, there would two cases for run_start: * aligned with HostPage means this is not partially dirty * not aligned means this is partially dirty When it is aligned, no work and calculation is necessary. run_start already points to the start of next HostPage and is ready to continue. When it is not aligned, the calculation could be simplified with: * fixup_start_addr =3D QEMU_ALIGN_DOWN(run_start, host_ratio) * run_start =3D QEMU_ALIGN_UP(run_start, host_ratio) By doing so, run_start always points to the next HostPage to check. fixup_start_addr always points to the HostPage to discard. Signed-off-by: Wei Yang Message-Id: <20190806004648.8659-2-richardw.yang@linux.intel.com> Reviewed-by: Dr. David Alan Gilbert Signed-off-by: Dr. David Alan Gilbert --- migration/ram.c | 34 +++++++--------------------------- 1 file changed, 7 insertions(+), 27 deletions(-) diff --git a/migration/ram.c b/migration/ram.c index f428639af5..d2184c3cfc 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -2955,7 +2955,6 @@ static void postcopy_chunk_hostpages_pass(Migration= State *ms, bool unsent_pass, } =20 while (run_start < pages) { - unsigned long fixup_start_addr; unsigned long host_offset; =20 /* @@ -2963,45 +2962,26 @@ static void postcopy_chunk_hostpages_pass(Migrati= onState *ms, bool unsent_pass, * page, then we need to fixup this host page. */ host_offset =3D run_start % host_ratio; - if (host_offset) { - fixup_start_addr =3D run_start - host_offset; - /* - * This host page has gone, the next loop iteration starts - * from after the fixup - */ - run_start =3D fixup_start_addr + host_ratio; - } else { + if (!host_offset) { /* Find the end of this run */ - unsigned long run_end; if (unsent_pass) { - run_end =3D find_next_bit(unsentmap, pages, run_start + = 1); + run_start =3D find_next_bit(unsentmap, pages, run_start = + 1); } else { - run_end =3D find_next_zero_bit(bitmap, pages, run_start = + 1); + run_start =3D find_next_zero_bit(bitmap, pages, run_star= t + 1); } /* * If the end isn't at the start of a host page, then the * run doesn't finish at the end of a host page * and we need to discard. */ - host_offset =3D run_end % host_ratio; - if (host_offset) { - fixup_start_addr =3D run_end - host_offset; - /* - * This host page has gone, the next loop iteration star= ts - * from after the fixup - */ - run_start =3D fixup_start_addr + host_ratio; - } else { - /* - * No discards on this iteration, next loop starts from - * next sent/dirty page - */ - run_start =3D run_end + 1; - } + host_offset =3D run_start % host_ratio; } =20 if (host_offset) { unsigned long page; + unsigned long fixup_start_addr =3D QEMU_ALIGN_DOWN(run_start= , + host_ratio)= ; + run_start =3D QEMU_ALIGN_UP(run_start, host_ratio); =20 /* Tell the destination to discard this page */ if (unsent_pass || !test_bit(fixup_start_addr, unsentmap)) { --=20 2.21.0