From patchwork Mon Jul 25 14:02:55 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Avi Kivity X-Patchwork-Id: 106675 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [140.186.70.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 9E78AB6F8C for ; Tue, 26 Jul 2011 00:04:02 +1000 (EST) Received: from localhost ([::1]:49456 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QlLlC-0004z8-RW for incoming@patchwork.ozlabs.org; Mon, 25 Jul 2011 10:03:54 -0400 Received: from eggs.gnu.org ([140.186.70.92]:47233) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QlLkX-0003ed-TD for qemu-devel@nongnu.org; Mon, 25 Jul 2011 10:03:18 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1QlLkU-00053M-Gj for qemu-devel@nongnu.org; Mon, 25 Jul 2011 10:03:13 -0400 Received: from mx1.redhat.com ([209.132.183.28]:31034) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QlLkU-00052D-8R for qemu-devel@nongnu.org; Mon, 25 Jul 2011 10:03:10 -0400 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id p6PE39ol008849 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Mon, 25 Jul 2011 10:03:09 -0400 Received: from cleopatra.tlv.redhat.com (cleopatra.tlv.redhat.com [10.35.255.11]) by int-mx10.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id p6PE387Q019015; Mon, 25 Jul 2011 10:03:09 -0400 Received: from s01.tlv.redhat.com (s01.tlv.redhat.com [10.35.255.8]) by cleopatra.tlv.redhat.com (Postfix) with ESMTP id F0C4D250B44; Mon, 25 Jul 2011 17:03:06 +0300 (IDT) From: Avi Kivity To: qemu-devel@nongnu.org Date: Mon, 25 Jul 2011 17:02:55 +0300 Message-Id: <1311602584-23409-15-git-send-email-avi@redhat.com> In-Reply-To: <1311602584-23409-1-git-send-email-avi@redhat.com> References: <1311602584-23409-1-git-send-email-avi@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.23 X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 209.132.183.28 Cc: kvm@vger.kernel.org Subject: [Qemu-devel] [PATCH 14/23] memory: transaction API X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Allow changes to the memory hierarchy to be accumulated and made visible all at once. This reduces computational effort, especially when an accelerator (e.g. kvm) is involved. Useful when a single register update causes multiple changes to an address space. Signed-off-by: Avi Kivity --- memory.c | 20 ++++++++++++++++++++ memory.h | 8 ++++++++ 2 files changed, 28 insertions(+), 0 deletions(-) diff --git a/memory.c b/memory.c index 009ad33..370e189 100644 --- a/memory.c +++ b/memory.c @@ -18,6 +18,8 @@ #include "kvm.h" #include +unsigned memory_region_transaction_depth = 0; + typedef struct AddrRange AddrRange; struct AddrRange { @@ -623,6 +625,10 @@ static void address_space_update_topology(AddressSpace *as) static void memory_region_update_topology(void) { + if (memory_region_transaction_depth) { + return; + } + if (address_space_memory.root) { address_space_update_topology(&address_space_memory); } @@ -631,6 +637,20 @@ static void memory_region_update_topology(void) } } +void memory_region_transaction_begin(void) +{ + ++memory_region_transaction_depth; +} + +void memory_region_transaction_commit(void) +{ + if (!memory_region_transaction_depth) { + abort(); + } + --memory_region_transaction_depth; + memory_region_update_topology(); +} + void memory_region_init(MemoryRegion *mr, const char *name, uint64_t size) diff --git a/memory.h b/memory.h index e4c0ad1..cb3a9b6 100644 --- a/memory.h +++ b/memory.h @@ -246,6 +246,14 @@ void memory_region_add_subregion_overlap(MemoryRegion *mr, void memory_region_del_subregion(MemoryRegion *mr, MemoryRegion *subregion); +/* Start a transaction; changes will be accumulated and made visible only + * when the transaction ends. + */ +void memory_region_transaction_begin(void); +/* Commit a transaction and make changes visible to the guest. + */ +void memory_region_transaction_commit(void); + #endif #endif