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 07D4EC76188 for ; Mon, 22 Jul 2019 06:40:22 +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 CED7121E6D for ; Mon, 22 Jul 2019 06:40:21 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CED7121E6D 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]:59190 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hpRzg-0007mO-Vm for qemu-devel@archiver.kernel.org; Mon, 22 Jul 2019 02:40:20 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:38691) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hpRzW-0007Nx-7B for qemu-devel@nongnu.org; Mon, 22 Jul 2019 02:40:11 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hpRzV-00007g-5E for qemu-devel@nongnu.org; Mon, 22 Jul 2019 02:40:10 -0400 Received: from mga04.intel.com ([192.55.52.120]:50840) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hpRzU-0008OG-Se for qemu-devel@nongnu.org; Mon, 22 Jul 2019 02:40:09 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga104.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 21 Jul 2019 23:40:06 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.64,294,1559545200"; d="scan'208";a="368419184" Received: from richard.sh.intel.com (HELO localhost) ([10.239.159.54]) by fmsmga006.fm.intel.com with ESMTP; 21 Jul 2019 23:40:05 -0700 Date: Mon, 22 Jul 2019 14:39:41 +0800 From: Wei Yang To: "Dr. David Alan Gilbert" Message-ID: <20190722063941.GA2602@richard> References: <20190710081111.10302-1-richardw.yang@linux.intel.com> <20190719174128.GI3000@work-vm> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190719174128.GI3000@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: 192.55.52.120 Subject: Re: [Qemu-devel] [PATCH] migration/postcopy: use static PostcopyDiscardState instead of allocating it for each block 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: quintela@redhat.com, Wei Yang , qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Fri, Jul 19, 2019 at 06:41:28PM +0100, Dr. David Alan Gilbert wrote: >* Wei Yang (richardw.yang@linux.intel.com) wrote: >> Even we need to do discard for each RAMBlock, we still can leverage the >> same memory space to store the information. >> >> By doing so, we avoid memory allocation and deallocation to the system >> and also avoid potential failure of memory allocation which breaks the >> migration. >> >> Signed-off-by: Wei Yang >> --- >> migration/postcopy-ram.c | 16 +++++++--------- >> 1 file changed, 7 insertions(+), 9 deletions(-) >> >> diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c >> index 9faacacc9e..2e6b076bb7 100644 >> --- a/migration/postcopy-ram.c >> +++ b/migration/postcopy-ram.c >> @@ -1377,8 +1377,7 @@ void postcopy_fault_thread_notify(MigrationIncomingState *mis) >> * asking to discard individual ranges. >> * >> * @ms: The current migration state. >> - * @offset: the bitmap offset of the named RAMBlock in the migration >> - * bitmap. >> + * @offset: the bitmap offset of the named RAMBlock in the migration bitmap. >> * @name: RAMBlock that discards will operate on. >> * >> * returns: a new PDS. >> @@ -1386,13 +1385,14 @@ void postcopy_fault_thread_notify(MigrationIncomingState *mis) >> PostcopyDiscardState *postcopy_discard_send_init(MigrationState *ms, >> const char *name) >> { >> - PostcopyDiscardState *res = g_malloc0(sizeof(PostcopyDiscardState)); >> + static PostcopyDiscardState res = {0}; > >Do you think it would be better to make this a static at the top of >migration/postcopy-ram.c and then we could remove the pds parameters >from postcopy_discard_send_range and friends? Just took a look into this one. One problem is not all its friends are in migration/postcopy-ram.c For example, postcopy_chunk_hostpages_pass() is in migration/ram.c. Which way do you prefer? >If there's only one pds then we don't need to pass the pointer around. > >Dave > >> - if (res) { >> - res->ramblock_name = name; >> - } >> + res.ramblock_name = name; >> + res.cur_entry = 0; >> + res.nsentwords = 0; >> + res.nsentcmds = 0; >> >> - return res; >> + return &res; >> } >> >> /** >> @@ -1449,8 +1449,6 @@ void postcopy_discard_send_finish(MigrationState *ms, PostcopyDiscardState *pds) >> >> trace_postcopy_discard_send_finish(pds->ramblock_name, pds->nsentwords, >> pds->nsentcmds); >> - >> - g_free(pds); >> } >> >> /* >> -- >> 2.17.1 >> >-- >Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK -- Wei Yang Help you, Help me