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=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 16F50C10F14 for ; Tue, 8 Oct 2019 17:45:54 +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 E53C1206B6 for ; Tue, 8 Oct 2019 17:45:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E53C1206B6 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]:59422 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iHtYW-0006mT-Dz for qemu-devel@archiver.kernel.org; Tue, 08 Oct 2019 13:45:52 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:49967) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iHtDq-0004xx-PB for qemu-devel@nongnu.org; Tue, 08 Oct 2019 13:24:31 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iHtDp-0006Kc-GV for qemu-devel@nongnu.org; Tue, 08 Oct 2019 13:24:30 -0400 Received: from mx1.redhat.com ([209.132.183.28]:33738) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iHtDp-0006KL-3A for qemu-devel@nongnu.org; Tue, 08 Oct 2019 13:24:29 -0400 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id ECC0F3082E03; Tue, 8 Oct 2019 17:24:27 +0000 (UTC) Received: from work-vm (ovpn-116-59.ams2.redhat.com [10.36.116.59]) by smtp.corp.redhat.com (Postfix) with ESMTPS id B77ED1001B35; Tue, 8 Oct 2019 17:24:25 +0000 (UTC) Date: Tue, 8 Oct 2019 18:24:23 +0100 From: "Dr. David Alan Gilbert" To: Wei Yang Subject: Re: [PATCH 2/2] migration/postcopy: map large zero page in postcopy_ram_incoming_setup() Message-ID: <20191008172423.GH3441@work-vm> References: <20191005135021.21721-1-richardw.yang@linux.intel.com> <20191005135021.21721-3-richardw.yang@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191005135021.21721-3-richardw.yang@linux.intel.com> User-Agent: Mutt/1.12.1 (2019-06-15) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.46]); Tue, 08 Oct 2019 17:24:27 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 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: qemu-devel@nongnu.org, quintela@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Wei Yang (richardw.yang@linux.intel.com) wrote: > postcopy_ram_incoming_setup() and postcopy_ram_incoming_cleanup() are > counterpart. It is reasonable to map/unmap large zero page in these two > functions respectively. > > Signed-off-by: Wei Yang Yes, OK. > --- > migration/postcopy-ram.c | 34 +++++++++++++++++----------------- > 1 file changed, 17 insertions(+), 17 deletions(-) > > diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c > index e554f93eec..813cfa5c42 100644 > --- a/migration/postcopy-ram.c > +++ b/migration/postcopy-ram.c > @@ -1142,6 +1142,22 @@ int postcopy_ram_incoming_setup(MigrationIncomingState *mis) > return -1; > } > > + /* > + * Map large zero page when kernel can't use UFFDIO_ZEROPAGE for hugepages > + */ > + mis->postcopy_tmp_zero_page = mmap(NULL, mis->largest_page_size, > + PROT_READ | PROT_WRITE, > + MAP_PRIVATE | MAP_ANONYMOUS, > + -1, 0); > + if (mis->postcopy_tmp_zero_page == MAP_FAILED) { > + int e = errno; > + mis->postcopy_tmp_zero_page = NULL; > + error_report("%s: Failed to map large zero page %s", > + __func__, strerror(e)); > + return -e; Note this starts returning -errno where the rest of this function returns 0 or -1; returning -errno is a good thing I think and it might be good to change the other returns. Reviewed-by: Dr. David Alan Gilbert > + } > + memset(mis->postcopy_tmp_zero_page, '\0', mis->largest_page_size); > + > /* > * Ballooning can mark pages as absent while we're postcopying > * that would cause false userfaults. > @@ -1248,23 +1264,7 @@ int postcopy_place_page_zero(MigrationIncomingState *mis, void *host, > qemu_ram_block_host_offset(rb, > host)); > } else { > - /* The kernel can't use UFFDIO_ZEROPAGE for hugepages */ > - if (!mis->postcopy_tmp_zero_page) { > - mis->postcopy_tmp_zero_page = mmap(NULL, mis->largest_page_size, > - PROT_READ | PROT_WRITE, > - MAP_PRIVATE | MAP_ANONYMOUS, > - -1, 0); > - if (mis->postcopy_tmp_zero_page == MAP_FAILED) { > - int e = errno; > - mis->postcopy_tmp_zero_page = NULL; > - error_report("%s: %s mapping large zero page", > - __func__, strerror(e)); > - return -e; > - } > - memset(mis->postcopy_tmp_zero_page, '\0', mis->largest_page_size); > - } > - return postcopy_place_page(mis, host, mis->postcopy_tmp_zero_page, > - rb); > + return postcopy_place_page(mis, host, mis->postcopy_tmp_zero_page, rb); > } > } > > -- > 2.17.1 > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK