From nobody Tue Nov 4 22:05:02 2025 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; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 153121449176011.264873188058118; Tue, 10 Jul 2018 02:21:31 -0700 (PDT) Received: from localhost ([::1]:46667 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fcopr-0004WE-BJ for importer@patchew.org; Tue, 10 Jul 2018 05:21:27 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54304) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fconh-0002xb-SQ for qemu-devel@nongnu.org; Tue, 10 Jul 2018 05:19:17 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fcong-0002vf-U2 for qemu-devel@nongnu.org; Tue, 10 Jul 2018 05:19:13 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:36598 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 1fcong-0002vS-OJ for qemu-devel@nongnu.org; Tue, 10 Jul 2018 05:19:12 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 5BE1281A4EAF; Tue, 10 Jul 2018 09:19:12 +0000 (UTC) Received: from xz-mi.redhat.com (ovpn-12-170.pek2.redhat.com [10.72.12.170]) by smtp.corp.redhat.com (Postfix) with ESMTP id B078C2166BA2; Tue, 10 Jul 2018 09:19:09 +0000 (UTC) From: Peter Xu To: qemu-devel@nongnu.org Date: Tue, 10 Jul 2018 17:18:53 +0800 Message-Id: <20180710091902.28780-2-peterx@redhat.com> In-Reply-To: <20180710091902.28780-1-peterx@redhat.com> References: <20180710091902.28780-1-peterx@redhat.com> X-Scanned-By: MIMEDefang 2.78 on 10.11.54.6 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Tue, 10 Jul 2018 09:19:12 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Tue, 10 Jul 2018 09:19:12 +0000 (UTC) for IP:'10.11.54.6' DOMAIN:'int-mx06.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'peterx@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] [PATCH for-3.0 v2 01/10] migration: simplify check to use qemu file buffer 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: Balamuruhan S , "Dr . David Alan Gilbert" , peterx@redhat.com, Juan Quintela 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" Firstly, renaming the old matching_page_sizes variable to matches_target_page_size, which suites more to what it did (it only checks against target page size rather than multiple page sizes). Meanwhile, simplify the check logic a bit, and enhance the comments. Should have no functional change. Reviewed-by: Dr. David Alan Gilbert Reviewed-by: Juan Quintela Signed-off-by: Peter Xu --- migration/ram.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) diff --git a/migration/ram.c b/migration/ram.c index 23cea47090..49068e86d3 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -3580,7 +3580,7 @@ static int ram_load_postcopy(QEMUFile *f) { int flags =3D 0, ret =3D 0; bool place_needed =3D false; - bool matching_page_sizes =3D false; + bool matches_target_page_size =3D false; MigrationIncomingState *mis =3D migration_incoming_get_current(); /* Temporary page that is later 'placed' */ void *postcopy_host_page =3D postcopy_get_tmp_page(mis); @@ -3620,7 +3620,7 @@ static int ram_load_postcopy(QEMUFile *f) ret =3D -EINVAL; break; } - matching_page_sizes =3D block->page_size =3D=3D TARGET_PAGE_SI= ZE; + matches_target_page_size =3D block->page_size =3D=3D TARGET_PA= GE_SIZE; /* * Postcopy requires that we place whole host pages atomically; * these may be huge pages for RAMBlocks that are backed by @@ -3668,12 +3668,17 @@ static int ram_load_postcopy(QEMUFile *f) =20 case RAM_SAVE_FLAG_PAGE: all_zero =3D false; - if (!place_needed || !matching_page_sizes) { + if (!matches_target_page_size) { + /* For huge pages, we always use temporary buffer */ qemu_get_buffer(f, page_buffer, TARGET_PAGE_SIZE); } else { - /* Avoids the qemu_file copy during postcopy, which is - * going to do a copy later; can only do it when we - * do this read in one go (matching page sizes) + /* + * For small pages that matches target page size, we + * avoid the qemu_file copy. Instead we directly use + * the buffer of QEMUFile to place the page. Note: we + * cannot do any QEMUFile operation before using that + * buffer to make sure the buffer is valid when + * placing the page. */ qemu_get_buffer_in_place(f, (uint8_t **)&place_source, TARGET_PAGE_SIZE); --=20 2.17.1