From patchwork Thu Nov 7 12:39:02 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wei Yang X-Patchwork-Id: 11232733 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 08012139A for ; Thu, 7 Nov 2019 12:41:30 +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 DD64B2187F for ; Thu, 7 Nov 2019 12:41:29 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DD64B2187F 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+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Received: from localhost ([::1]:41644 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iSh6O-00062a-Tz for patchwork-qemu-devel@patchwork.kernel.org; Thu, 07 Nov 2019 07:41:28 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:58910) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iSh4e-0003wb-Me for qemu-devel@nongnu.org; Thu, 07 Nov 2019 07:39:41 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iSh4d-0002qa-Nb for qemu-devel@nongnu.org; Thu, 07 Nov 2019 07:39:40 -0500 Received: from mga06.intel.com ([134.134.136.31]:63430) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iSh4d-0002nd-Fw for qemu-devel@nongnu.org; Thu, 07 Nov 2019 07:39:39 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by orsmga104.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 07 Nov 2019 04:39:36 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.68,278,1569308400"; d="scan'208";a="377408585" Received: from richard.sh.intel.com (HELO localhost) ([10.239.159.54]) by orsmga005.jf.intel.com with ESMTP; 07 Nov 2019 04:39:35 -0800 From: Wei Yang To: quintela@redhat.com, dgilbert@redhat.com Subject: [Patch v2 1/6] migration/postcopy: reduce memset when it is zero page and matches_target_page_size Date: Thu, 7 Nov 2019 20:39:02 +0800 Message-Id: <20191107123907.29791-2-richardw.yang@linux.intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20191107123907.29791-1-richardw.yang@linux.intel.com> References: <20191107123907.29791-1-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+patchwork-qemu-devel=patchwork.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 Reviewed-by: Dr. David Alan Gilbert Acked-by: Juan Quintela --- 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; }