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 21702ECE58D for ; Thu, 10 Oct 2019 01:22:25 +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 F014A21848 for ; Thu, 10 Oct 2019 01:22:24 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F014A21848 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]:33178 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iIN9s-0006bc-4g for qemu-devel@archiver.kernel.org; Wed, 09 Oct 2019 21:22:24 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:49755) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iIN9F-0006AF-1v for qemu-devel@nongnu.org; Wed, 09 Oct 2019 21:21:46 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iIN9D-0007r6-SV for qemu-devel@nongnu.org; Wed, 09 Oct 2019 21:21:45 -0400 Received: from mga01.intel.com ([192.55.52.88]:56984) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iIN9D-0007qs-K5 for qemu-devel@nongnu.org; Wed, 09 Oct 2019 21:21:43 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from orsmga003.jf.intel.com ([10.7.209.27]) by fmsmga101.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 09 Oct 2019 18:21:41 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.67,278,1566889200"; d="scan'208";a="197089351" Received: from richard.sh.intel.com (HELO localhost) ([10.239.159.54]) by orsmga003.jf.intel.com with ESMTP; 09 Oct 2019 18:21:40 -0700 Date: Thu, 10 Oct 2019 09:21:23 +0800 From: Wei Yang To: "Dr. David Alan Gilbert" Subject: Re: [PATCH 3/3] migration/postcopy: replace have_listen_thread check with PostcopyState check Message-ID: <20191010012123.GA2167@richard> References: <20191006000249.29926-1-richardw.yang@linux.intel.com> <20191006000249.29926-4-richardw.yang@linux.intel.com> <20191008191551.GN3441@work-vm> <20191009013733.GF26203@richard> <20191009101716.GH2893@work-vm> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191009101716.GH2893@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: 192.55.52.88 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, Oct 09, 2019 at 11:17:16AM +0100, Dr. David Alan Gilbert wrote: >* Wei Yang (richardw.yang@linux.intel.com) wrote: >> On Tue, Oct 08, 2019 at 08:15:51PM +0100, Dr. David Alan Gilbert wrote: >> >* Wei Yang (richardw.yang@linux.intel.com) wrote: >> >> After previous cleanup, postcopy thread is running only when >> >> PostcopyState is LISTENNING or RUNNING. This means it is not necessary >> >> to spare a variable have_listen_thread to represent the state. >> >> >> >> Replace the check on have_listen_thread with PostcopyState and remove >> >> the variable. >> >> >> >> Signed-off-by: Wei Yang >> >> --- >> >> migration/migration.h | 1 - >> >> migration/ram.c | 2 +- >> >> migration/ram.h | 1 + >> >> migration/savevm.c | 4 +--- >> >> 4 files changed, 3 insertions(+), 5 deletions(-) >> >> >> >> diff --git a/migration/migration.h b/migration/migration.h >> >> index 4f2fe193dc..a4d639663d 100644 >> >> --- a/migration/migration.h >> >> +++ b/migration/migration.h >> >> @@ -63,7 +63,6 @@ struct MigrationIncomingState { >> >> /* Set this when we want the fault thread to quit */ >> >> bool fault_thread_quit; >> >> >> >> - bool have_listen_thread; >> >> QemuThread listen_thread; >> >> QemuSemaphore listen_thread_sem; >> >> >> >> diff --git a/migration/ram.c b/migration/ram.c >> >> index 769d3f6454..dfc50d57d5 100644 >> >> --- a/migration/ram.c >> >> +++ b/migration/ram.c >> >> @@ -4188,7 +4188,7 @@ static bool postcopy_is_advised(void) >> >> return ps >= POSTCOPY_INCOMING_ADVISE && ps < POSTCOPY_INCOMING_END; >> >> } >> >> >> >> -static bool postcopy_is_running(void) >> >> +bool postcopy_is_running(void) >> >> { >> >> PostcopyState ps = postcopy_state_get(); >> >> return ps >= POSTCOPY_INCOMING_LISTENING && ps < POSTCOPY_INCOMING_END; >> >> diff --git a/migration/ram.h b/migration/ram.h >> >> index bd0eee79b6..44fe4753ad 100644 >> >> --- a/migration/ram.h >> >> +++ b/migration/ram.h >> >> @@ -59,6 +59,7 @@ int ram_postcopy_send_discard_bitmap(MigrationState *ms); >> >> /* For incoming postcopy discard */ >> >> int ram_discard_range(const char *block_name, uint64_t start, size_t length); >> >> int ram_postcopy_incoming_init(MigrationIncomingState *mis); >> >> +bool postcopy_is_running(void); >> >> >> >> void ram_handle_compressed(void *host, uint8_t ch, uint64_t size); >> >> >> >> diff --git a/migration/savevm.c b/migration/savevm.c >> >> index dcad8897a3..2a0e0b94df 100644 >> >> --- a/migration/savevm.c >> >> +++ b/migration/savevm.c >> >> @@ -1836,7 +1836,6 @@ static void *postcopy_ram_listen_thread(void *opaque) >> >> qemu_loadvm_state_cleanup(); >> >> >> >> rcu_unregister_thread(); >> >> - mis->have_listen_thread = false; >> >> postcopy_state_set(POSTCOPY_INCOMING_END, NULL); >> > >> >That now needs a big comment saying it must be the last thing in the >> >thread, because now it's got meaning that it's here. >> > >> >> >> >> return NULL; >> >> @@ -1880,7 +1879,6 @@ static int loadvm_postcopy_handle_listen(MigrationIncomingState *mis) >> >> return -1; >> >> } >> >> >> >> - mis->have_listen_thread = true; >> >> /* Start up the listening thread and wait for it to signal ready */ >> >> qemu_sem_init(&mis->listen_thread_sem, 0); >> >> qemu_thread_create(&mis->listen_thread, "postcopy/listen", >> >> @@ -2518,7 +2516,7 @@ int qemu_loadvm_state(QEMUFile *f) >> >> >> >> trace_qemu_loadvm_state_post_main(ret); >> >> >> >> - if (mis->have_listen_thread) { >> >> + if (postcopy_is_running()) { >> >> /* Listen thread still going, can't clean up yet */ >> >> return ret; >> >> } >> > >> >Can you explain to me why this is afe in the case of a failure in >> >loadvm_postcopy_handle_listen between the start where it sets >> >the state to LISTENING, and the point where it currently sets >> >hasve_listen_thread ? Wouldn't this cause qemu_loadvm_state >> >not to cleanup? >> > >> >> I have to say you are right. listen_thread may not started when PostcopyState >> is already set to LISTENING. >> >> The ugly fix may be set PostcopyState back to original one. Not sure whether >> you would like this. > >I think the 'have_listen_thread' might be the simplest solution though; >it's very simple! > Yep, you are right. >Dave > >> >Dave >> > >> >> -- >> >> 2.17.1 >> >> >> >-- >> >Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK >> >> -- >> Wei Yang >> Help you, Help me >-- >Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK -- Wei Yang Help you, Help me