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=-9.7 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_GIT 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 70A1CCA9EC8 for ; Fri, 18 Oct 2019 00:50:32 +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 485AC21852 for ; Fri, 18 Oct 2019 00:50:32 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 485AC21852 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]:34410 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iLGTP-0005l3-DT for qemu-devel@archiver.kernel.org; Thu, 17 Oct 2019 20:50:31 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:49235) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iLGSJ-0004Pu-2V for qemu-devel@nongnu.org; Thu, 17 Oct 2019 20:49:24 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iLGSI-000172-4D for qemu-devel@nongnu.org; Thu, 17 Oct 2019 20:49:22 -0400 Received: from mga06.intel.com ([134.134.136.31]:15620) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iLGSH-00010g-Sx for qemu-devel@nongnu.org; Thu, 17 Oct 2019 20:49:22 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga003.jf.intel.com ([10.7.209.27]) by orsmga104.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 17 Oct 2019 17:49:15 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.67,309,1566889200"; d="scan'208";a="199552617" Received: from richard.sh.intel.com (HELO localhost) ([10.239.159.54]) by orsmga003.jf.intel.com with ESMTP; 17 Oct 2019 17:49:14 -0700 From: Wei Yang To: quintela@redhat.com, dgilbert@redhat.com Subject: [PATCH 1/6] migration/postcopy: reduce memset when it is zero page and matches_target_page_size Date: Fri, 18 Oct 2019 08:48:45 +0800 Message-Id: <20191018004850.9888-2-richardw.yang@linux.intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20191018004850.9888-1-richardw.yang@linux.intel.com> References: <20191018004850.9888-1-richardw.yang@linux.intel.com> X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 134.134.136.31 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, Wei Yang Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" In this case, page_buffer content would not be used. Skip this to save some time. Signed-off-by: Wei Yang --- migration/ram.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/migration/ram.c b/migration/ram.c index 99a98b2da4..7938a643d9 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -4091,7 +4091,13 @@ static int ram_load_postcopy(QEMUFile *f) switch (flags & ~RAM_SAVE_FLAG_CONTINUE) { case RAM_SAVE_FLAG_ZERO: ch = qemu_get_byte(f); - memset(page_buffer, ch, TARGET_PAGE_SIZE); + /* + * Can skip to set page_buffer when + * this is a zero page and (block->page_size == TARGET_PAGE_SIZE). + */ + if (ch || !matches_target_page_size) { + memset(page_buffer, ch, TARGET_PAGE_SIZE); + } if (ch) { all_zero = false; } -- 2.17.1