From patchwork Thu Sep 26 09:45:24 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Xia, Hongyan" X-Patchwork-Id: 11162081 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 5486513B1 for ; Thu, 26 Sep 2019 09:49:24 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (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 23578222C4 for ; Thu, 26 Sep 2019 09:49:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="QxtzOIPw" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 23578222C4 Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=amazon.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1iDQNd-0004AT-Qc; Thu, 26 Sep 2019 09:48:09 +0000 Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1iDQNc-00049A-B8 for xen-devel@lists.xenproject.org; Thu, 26 Sep 2019 09:48:08 +0000 X-Inumbo-ID: bd9b7079-e042-11e9-964c-12813bfff9fa Received: from smtp-fw-33001.amazon.com (unknown [207.171.190.10]) by localhost (Halon) with ESMTPS id bd9b7079-e042-11e9-964c-12813bfff9fa; Thu, 26 Sep 2019 09:48:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1569491288; x=1601027288; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version; bh=dzdF87SizyQOXNy95CNVyj6xRv19mPnErY+Ua4/etgQ=; b=QxtzOIPwyS19O/2NCHjPysKb3smqueOVRlVY7hF/SYrYHPivpg2fbzj7 jkjD/dckg67CGdAwbWSSdDEBh96OL1gCPFqE/LjMVhCTTgzXNl+QWQFNA nDQNP+l4R+khll/UC9w9AyYD6NRW9xZcHmEBxeJAHe0XROZoKMIpHWclU Y=; X-IronPort-AV: E=Sophos;i="5.64,551,1559520000"; d="scan'208";a="836988546" Received: from sea3-co-svc-lb6-vlan2.sea.amazon.com (HELO email-inbound-relay-1a-821c648d.us-east-1.amazon.com) ([10.47.22.34]) by smtp-border-fw-out-33001.sea14.amazon.com with ESMTP; 26 Sep 2019 09:47:08 +0000 Received: from EX13MTAUWA001.ant.amazon.com (iad55-ws-svc-p15-lb9-vlan3.iad.amazon.com [10.40.159.166]) by email-inbound-relay-1a-821c648d.us-east-1.amazon.com (Postfix) with ESMTPS id BA090A238B; Thu, 26 Sep 2019 09:46:55 +0000 (UTC) Received: from EX13D13UWA001.ant.amazon.com (10.43.160.136) by EX13MTAUWA001.ant.amazon.com (10.43.160.118) with Microsoft SMTP Server (TLS) id 15.0.1367.3; Thu, 26 Sep 2019 09:46:55 +0000 Received: from EX13MTAUWA001.ant.amazon.com (10.43.160.58) by EX13D13UWA001.ant.amazon.com (10.43.160.136) with Microsoft SMTP Server (TLS) id 15.0.1367.3; Thu, 26 Sep 2019 09:46:54 +0000 Received: from u9d785c4ba99158.ant.amazon.com (10.125.106.58) by mail-relay.amazon.com (10.43.160.118) with Microsoft SMTP Server id 15.0.1367.3 via Frontend Transport; Thu, 26 Sep 2019 09:46:53 +0000 From: To: Date: Thu, 26 Sep 2019 10:45:24 +0100 Message-ID: X-Mailer: git-send-email 2.17.1 In-Reply-To: References: MIME-Version: 1.0 Precedence: Bulk Subject: [Xen-devel] [RFC PATCH 01/84] x86/mm: defer clearing page in virt_to_xen_lXe X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.23 List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: Andrew Cooper , Wei Liu , Wei Liu , Jan Beulich , =?utf-8?q?Roger_Pau_?= =?utf-8?q?Monn=C3=A9?= Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" From: Wei Liu Defer the call to clear_page to the point when we're sure the page is going to become a page table. This is a minor optimisation. No functional change. Signed-off-by: Wei Liu --- xen/arch/x86/mm.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c index 99816fc67c..e90c8a63a6 100644 --- a/xen/arch/x86/mm.c +++ b/xen/arch/x86/mm.c @@ -4879,13 +4879,13 @@ static l3_pgentry_t *virt_to_xen_l3e(unsigned long v) if ( !pl3e ) return NULL; - clear_page(pl3e); if ( locking ) spin_lock(&map_pgdir_lock); if ( !(l4e_get_flags(*pl4e) & _PAGE_PRESENT) ) { l4_pgentry_t l4e = l4e_from_paddr(__pa(pl3e), __PAGE_HYPERVISOR); + clear_page(pl3e); l4e_write(pl4e, l4e); efi_update_l4_pgtable(l4_table_offset(v), l4e); pl3e = NULL; @@ -4914,11 +4914,11 @@ static l2_pgentry_t *virt_to_xen_l2e(unsigned long v) if ( !pl2e ) return NULL; - clear_page(pl2e); if ( locking ) spin_lock(&map_pgdir_lock); if ( !(l3e_get_flags(*pl3e) & _PAGE_PRESENT) ) { + clear_page(pl2e); l3e_write(pl3e, l3e_from_paddr(__pa(pl2e), __PAGE_HYPERVISOR)); pl2e = NULL; } @@ -4947,11 +4947,11 @@ l1_pgentry_t *virt_to_xen_l1e(unsigned long v) if ( !pl1e ) return NULL; - clear_page(pl1e); if ( locking ) spin_lock(&map_pgdir_lock); if ( !(l2e_get_flags(*pl2e) & _PAGE_PRESENT) ) { + clear_page(pl1e); l2e_write(pl2e, l2e_from_paddr(__pa(pl1e), __PAGE_HYPERVISOR)); pl1e = NULL; }