From patchwork Mon Sep 30 10:32:53 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Xia, Hongyan" X-Patchwork-Id: 11166373 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 3D7AC1709 for ; Mon, 30 Sep 2019 10:35:21 +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 1A3552190F for ; Mon, 30 Sep 2019 10:35:21 +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="GzXlXKTL" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1A3552190F 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 1iEt0G-0006m7-8t; Mon, 30 Sep 2019 10:34:04 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1iEt0E-0006lg-UR for xen-devel@lists.xenproject.org; Mon, 30 Sep 2019 10:34:02 +0000 X-Inumbo-ID: d1ce6874-e36d-11e9-bf31-bc764e2007e4 Received: from smtp-fw-2101.amazon.com (unknown [72.21.196.25]) by localhost (Halon) with ESMTPS id d1ce6874-e36d-11e9-bf31-bc764e2007e4; Mon, 30 Sep 2019 10:34:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1569839642; x=1601375642; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version; bh=dzdF87SizyQOXNy95CNVyj6xRv19mPnErY+Ua4/etgQ=; b=GzXlXKTL1aFrLXoDctGCNU52JFR8VJWA1ydzJ5xlVNwn2J2C+zmaPi03 pYNvD1+uDVTVVOReSVkQQGevySv8ergCLKG62CXIfr81XQkB9KxLjru84 CuWQVYxRBtwlbUDLytYGrjwwCGL0KrQPH5YGIk79BlJF/k79QMSoydFc3 w=; X-IronPort-AV: E=Sophos;i="5.64,565,1559520000"; d="scan'208";a="754242139" Received: from iad6-co-svc-p1-lb1-vlan2.amazon.com (HELO email-inbound-relay-1a-821c648d.us-east-1.amazon.com) ([10.124.125.2]) by smtp-border-fw-out-2101.iad2.amazon.com with ESMTP; 30 Sep 2019 10:34:01 +0000 Received: from EX13MTAUEA001.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 A41C6A24F7; Mon, 30 Sep 2019 10:33:50 +0000 (UTC) Received: from EX13D02UEE002.ant.amazon.com (10.43.62.231) by EX13MTAUEA001.ant.amazon.com (10.43.61.82) with Microsoft SMTP Server (TLS) id 15.0.1367.3; Mon, 30 Sep 2019 10:33:50 +0000 Received: from EX13MTAUEE001.ant.amazon.com (10.43.62.200) by EX13D02UEE002.ant.amazon.com (10.43.62.231) with Microsoft SMTP Server (TLS) id 15.0.1367.3; Mon, 30 Sep 2019 10:33:49 +0000 Received: from u9d785c4ba99158.ant.amazon.com (10.125.106.78) by mail-relay.amazon.com (10.43.62.226) with Microsoft SMTP Server id 15.0.1367.3 via Frontend Transport; Mon, 30 Sep 2019 10:33:49 +0000 From: Hongyan Xia To: Date: Mon, 30 Sep 2019 11:32:53 +0100 Message-ID: X-Mailer: git-send-email 2.17.1 In-Reply-To: References: MIME-Version: 1.0 Precedence: Bulk Subject: [Xen-devel] [PATCH v2 01/55] 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 , Jan Beulich , =?utf-8?q?Roger_Pau_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; }