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, 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 7FA10C5DF60 for ; Thu, 7 Nov 2019 06:01:18 +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 4CD3921882 for ; Thu, 7 Nov 2019 06:01:18 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4CD3921882 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:39138 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iSar7-0006YS-Fz for qemu-devel@archiver.kernel.org; Thu, 07 Nov 2019 01:01:17 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:33620) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iSaqP-00063C-60 for qemu-devel@nongnu.org; Thu, 07 Nov 2019 01:00:34 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iSaqN-0002fL-TW for qemu-devel@nongnu.org; Thu, 07 Nov 2019 01:00:33 -0500 Received: from mga09.intel.com ([134.134.136.24]:36796) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iSaqN-0002Mw-KA for qemu-devel@nongnu.org; Thu, 07 Nov 2019 01:00:31 -0500 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga102.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 06 Nov 2019 22:00:23 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.68,276,1569308400"; d="scan'208";a="233146158" Received: from richard.sh.intel.com (HELO localhost) ([10.239.159.54]) by fmsmga002.fm.intel.com with ESMTP; 06 Nov 2019 22:00:22 -0800 Date: Thu, 7 Nov 2019 14:00:11 +0800 From: Wei Yang To: "Dr. David Alan Gilbert" Subject: Re: [PATCH 5/6] migration/postcopy: enable random order target page arrival Message-ID: <20191107060010.GA13394@richard> References: <20191018004850.9888-1-richardw.yang@linux.intel.com> <20191018004850.9888-6-richardw.yang@linux.intel.com> <20191106200828.GL2802@work-vm> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191106200828.GL2802@work-vm> User-Agent: Mutt/1.9.4 (2018-02-28) X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 134.134.136.24 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: , Reply-To: Wei Yang Cc: qemu-devel@nongnu.org, Wei Yang , quintela@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Wed, Nov 06, 2019 at 08:08:28PM +0000, Dr. David Alan Gilbert wrote: >* Wei Yang (richardw.yang@linux.intel.com) wrote: >> After using number of target page received to track one host page, we >> could have the capability to handle random order target page arrival in >> one host page. >> >> This is a preparation for enabling compress during postcopy. >> >> Signed-off-by: Wei Yang >> --- >> migration/ram.c | 16 +++------------- >> 1 file changed, 3 insertions(+), 13 deletions(-) >> >> diff --git a/migration/ram.c b/migration/ram.c >> index b5759793a9..da0596411c 100644 >> --- a/migration/ram.c >> +++ b/migration/ram.c >> @@ -4015,7 +4015,6 @@ static int ram_load_postcopy(QEMUFile *f) >> MigrationIncomingState *mis = migration_incoming_get_current(); >> /* Temporary page that is later 'placed' */ >> void *postcopy_host_page = mis->postcopy_tmp_page; >> - void *last_host = NULL; >> bool all_zero = false; >> int target_pages = 0; >> >> @@ -4062,24 +4061,15 @@ static int ram_load_postcopy(QEMUFile *f) >> * that's moved into place later. >> * The migration protocol uses, possibly smaller, target-pages >> * however the source ensures it always sends all the components >> - * of a host page in order. >> + * of a host page in one chunk. >> */ >> page_buffer = postcopy_host_page + >> ((uintptr_t)host & (block->page_size - 1)); >> /* If all TP are zero then we can optimise the place */ >> if (target_pages == 1) { >> all_zero = true; >> - } else { >> - /* not the 1st TP within the HP */ >> - if (host != (last_host + TARGET_PAGE_SIZE)) { >> - error_report("Non-sequential target page %p/%p", >> - host, last_host); >> - ret = -EINVAL; >> - break; >> - } > >I think this is losing more protection than needed. >I think you can still protect against a page from a different host-page >arriving until we've placed the current host-page. >So something like: > > if (((uintptr_t)host & ~(block->page_size - 1)) != > last_host) > OK, looks reasonable. >and then set last_host to the start of the host page. > I think it is not necessary to update the last_host on each target page. We can just set it at the first target page. >Then you'll check if that flush is really working. > >Dave > >> } >> >> - >> /* >> * If it's the last part of a host page then we place the host >> * page >> @@ -4090,7 +4080,6 @@ static int ram_load_postcopy(QEMUFile *f) >> } >> place_source = postcopy_host_page; >> } >> - last_host = host; >> >> switch (flags & ~RAM_SAVE_FLAG_CONTINUE) { >> case RAM_SAVE_FLAG_ZERO: >> @@ -4143,7 +4132,8 @@ static int ram_load_postcopy(QEMUFile *f) >> >> if (!ret && place_needed) { >> /* This gets called at the last target page in the host page */ >> - void *place_dest = host + TARGET_PAGE_SIZE - block->page_size; >> + void *place_dest = (void *)QEMU_ALIGN_DOWN((unsigned long)host, >> + block->page_size); >> >> if (all_zero) { >> ret = postcopy_place_page_zero(mis, place_dest, >> -- >> 2.17.1 >> >-- >Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK -- Wei Yang Help you, Help me