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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,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 5DEB8C10F14 for ; Tue, 8 Oct 2019 17:44:57 +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 3B7CB2070B for ; Tue, 8 Oct 2019 17:44:57 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3B7CB2070B 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]:59410 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iHtXb-0005qI-Fs for qemu-devel@archiver.kernel.org; Tue, 08 Oct 2019 13:44:55 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:49274) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iHt8Z-0007ue-UJ for qemu-devel@nongnu.org; Tue, 08 Oct 2019 13:19:05 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iHt8W-0002pq-9H for qemu-devel@nongnu.org; Tue, 08 Oct 2019 13:19:02 -0400 Received: from mx1.redhat.com ([209.132.183.28]:35926) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iHt8V-0002p2-9b for qemu-devel@nongnu.org; Tue, 08 Oct 2019 13:18:59 -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 C51613003715; Tue, 8 Oct 2019 17:18:57 +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 EB6C61001DC0; Tue, 8 Oct 2019 17:18:56 +0000 (UTC) Date: Tue, 8 Oct 2019 18:18:54 +0100 From: "Dr. David Alan Gilbert" To: Wei Yang Subject: Re: [PATCH 1/2] migration/postcopy: allocate tmp_page in setup stage Message-ID: <20191008171854.GG3441@work-vm> References: <20191005135021.21721-1-richardw.yang@linux.intel.com> <20191005135021.21721-2-richardw.yang@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191005135021.21721-2-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 [10.5.110.47]); Tue, 08 Oct 2019 17:18:57 +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: > During migration, a tmp page is allocated so that we could place a whole > host page during postcopy. > > Currently the page is allocated during load stage, this is a little bit > late. And more important, if we failed to allocate it, the error is not > checked properly. Even it is NULL, we would still use it. Oops, yes. Reviewed-by: Dr. David Alan Gilbert > > This patch moves the allocation to setup stage and if failed error > message would be printed and caller would notice it. > > Signed-off-by: Wei Yang > --- > migration/postcopy-ram.c | 40 ++++++++++------------------------------ > migration/postcopy-ram.h | 7 ------- > migration/ram.c | 2 +- > 3 files changed, 11 insertions(+), 38 deletions(-) > > diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c > index 51dc164693..e554f93eec 100644 > --- a/migration/postcopy-ram.c > +++ b/migration/postcopy-ram.c > @@ -1132,6 +1132,16 @@ int postcopy_ram_incoming_setup(MigrationIncomingState *mis) > return -1; > } > > + mis->postcopy_tmp_page = mmap(NULL, mis->largest_page_size, > + PROT_READ | PROT_WRITE, MAP_PRIVATE | > + MAP_ANONYMOUS, -1, 0); > + if (mis->postcopy_tmp_page == MAP_FAILED) { > + mis->postcopy_tmp_page = NULL; > + error_report("%s: Failed to map postcopy_tmp_page %s", > + __func__, strerror(errno)); > + return -1; > + } > + > /* > * Ballooning can mark pages as absent while we're postcopying > * that would cause false userfaults. > @@ -1258,30 +1268,6 @@ int postcopy_place_page_zero(MigrationIncomingState *mis, void *host, > } > } > > -/* > - * Returns a target page of memory that can be mapped at a later point in time > - * using postcopy_place_page > - * The same address is used repeatedly, postcopy_place_page just takes the > - * backing page away. > - * Returns: Pointer to allocated page > - * > - */ > -void *postcopy_get_tmp_page(MigrationIncomingState *mis) > -{ > - if (!mis->postcopy_tmp_page) { > - mis->postcopy_tmp_page = mmap(NULL, mis->largest_page_size, > - PROT_READ | PROT_WRITE, MAP_PRIVATE | > - MAP_ANONYMOUS, -1, 0); > - if (mis->postcopy_tmp_page == MAP_FAILED) { > - mis->postcopy_tmp_page = NULL; > - error_report("%s: %s", __func__, strerror(errno)); > - return NULL; > - } > - } > - > - return mis->postcopy_tmp_page; > -} > - > #else > /* No target OS support, stubs just fail */ > void fill_destination_postcopy_migration_info(MigrationInfo *info) > @@ -1339,12 +1325,6 @@ int postcopy_place_page_zero(MigrationIncomingState *mis, void *host, > return -1; > } > > -void *postcopy_get_tmp_page(MigrationIncomingState *mis) > -{ > - assert(0); > - return NULL; > -} > - > int postcopy_wake_shared(struct PostCopyFD *pcfd, > uint64_t client_addr, > RAMBlock *rb) > diff --git a/migration/postcopy-ram.h b/migration/postcopy-ram.h > index e3dde32155..c0ccf64a96 100644 > --- a/migration/postcopy-ram.h > +++ b/migration/postcopy-ram.h > @@ -100,13 +100,6 @@ typedef enum { > POSTCOPY_INCOMING_END > } PostcopyState; > > -/* > - * Allocate a page of memory that can be mapped at a later point in time > - * using postcopy_place_page > - * Returns: Pointer to allocated page > - */ > -void *postcopy_get_tmp_page(MigrationIncomingState *mis); > - > PostcopyState postcopy_state_get(void); > /* Set the state and return the old state */ > PostcopyState postcopy_state_set(PostcopyState new_state, > diff --git a/migration/ram.c b/migration/ram.c > index 4c15162bd6..adbaf0b11a 100644 > --- a/migration/ram.c > +++ b/migration/ram.c > @@ -4048,7 +4048,7 @@ static int ram_load_postcopy(QEMUFile *f) > bool matches_target_page_size = false; > MigrationIncomingState *mis = migration_incoming_get_current(); > /* Temporary page that is later 'placed' */ > - void *postcopy_host_page = postcopy_get_tmp_page(mis); > + void *postcopy_host_page = mis->postcopy_tmp_page; > void *last_host = NULL; > bool all_zero = false; > > -- > 2.17.1 > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK