From patchwork Wed Jan 10 14:25:15 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paolo Bonzini X-Patchwork-Id: 858319 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=nongnu.org (client-ip=2001:4830:134:3::11; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3zGrwZ0sRrz9s72 for ; Thu, 11 Jan 2018 01:28:46 +1100 (AEDT) Received: from localhost ([::1]:45114 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eZHMy-0005ws-2m for incoming@patchwork.ozlabs.org; Wed, 10 Jan 2018 09:28:44 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53815) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eZHJs-0003kh-Mx for qemu-devel@nongnu.org; Wed, 10 Jan 2018 09:25:33 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eZHJr-0000cV-IO for qemu-devel@nongnu.org; Wed, 10 Jan 2018 09:25:32 -0500 Received: from mx1.redhat.com ([209.132.183.28]:58935) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1eZHJq-0000bk-Vh for qemu-devel@nongnu.org; Wed, 10 Jan 2018 09:25:31 -0500 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 0917E50F58 for ; Wed, 10 Jan 2018 14:25:30 +0000 (UTC) Received: from donizetti.mxp.redhat.com (unknown [10.32.181.235]) by smtp.corp.redhat.com (Postfix) with ESMTP id EA31417CD0; Wed, 10 Jan 2018 14:25:24 +0000 (UTC) From: Paolo Bonzini To: qemu-devel@nongnu.org Date: Wed, 10 Jan 2018 15:25:15 +0100 Message-Id: <20180110142515.13242-3-pbonzini@redhat.com> In-Reply-To: <20180110142515.13242-1-pbonzini@redhat.com> References: <20180110142515.13242-1-pbonzini@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Wed, 10 Jan 2018 14:25:30 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH 2/2] find_ram_offset: Align ram_addr_t allocation on long boundaries X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: dgilbert@redhat.com, quintela@redhat.com Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" From: "Dr. David Alan Gilbert" The dirty bitmaps are built from 'long's and there is fast-path code for synchronising the case where the RAMBlock is aligned to the start of a long boundary. Align the allocation to this boundary to cause the fast path to be used. Offsets before change: 11398@1515169675.018566:find_ram_offset size: 0x1e0000 @ 0x8000000 11398@1515169675.020064:find_ram_offset size: 0x20000 @ 0x81e0000 11398@1515169675.020244:find_ram_offset size: 0x20000 @ 0x8200000 11398@1515169675.024343:find_ram_offset size: 0x1000000 @ 0x8220000 11398@1515169675.025154:find_ram_offset size: 0x10000 @ 0x9220000 11398@1515169675.027682:find_ram_offset size: 0x40000 @ 0x9230000 11398@1515169675.032921:find_ram_offset size: 0x200000 @ 0x9270000 11398@1515169675.033307:find_ram_offset size: 0x1000 @ 0x9470000 11398@1515169675.033601:find_ram_offset size: 0x1000 @ 0x9471000 after change: 10923@1515169108.818245:find_ram_offset size: 0x1e0000 @ 0x8000000 10923@1515169108.819410:find_ram_offset size: 0x20000 @ 0x8200000 10923@1515169108.819587:find_ram_offset size: 0x20000 @ 0x8240000 10923@1515169108.823708:find_ram_offset size: 0x1000000 @ 0x8280000 10923@1515169108.824503:find_ram_offset size: 0x10000 @ 0x9280000 10923@1515169108.827093:find_ram_offset size: 0x40000 @ 0x92c0000 10923@1515169108.833045:find_ram_offset size: 0x200000 @ 0x9300000 10923@1515169108.833504:find_ram_offset size: 0x1000 @ 0x9500000 10923@1515169108.833787:find_ram_offset size: 0x1000 @ 0x9540000 Suggested-by: Paolo Bonzini Signed-off-by: Dr. David Alan Gilbert Message-Id: <20180105170138.23357-3-dgilbert@redhat.com> Signed-off-by: Paolo Bonzini --- exec.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/exec.c b/exec.c index 829f9d8d1a..c543b54094 100644 --- a/exec.c +++ b/exec.c @@ -1679,7 +1679,11 @@ static ram_addr_t find_ram_offset(ram_addr_t size) RAMBLOCK_FOREACH(block) { ram_addr_t candidate, next = RAM_ADDR_MAX; + /* Align blocks to start on a 'long' in the bitmap + * which makes the bitmap sync'ing take the fast path. + */ candidate = block->offset + block->max_length; + candidate = ROUND_UP(candidate, BITS_PER_LONG << TARGET_PAGE_BITS); /* Search for the closest following block * and find the gap.