From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org 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 smtp.lore.kernel.org (Postfix) with ESMTPS id DF24CC71136 for ; Mon, 16 Jun 2025 21:19:13 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1uRHDd-0002Tr-44; Mon, 16 Jun 2025 17:18:17 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1uRHDW-0002Sk-Dn for qemu-devel@nongnu.org; Mon, 16 Jun 2025 17:18:12 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1uRHDT-0005Kz-KM for qemu-devel@nongnu.org; Mon, 16 Jun 2025 17:18:09 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1750108686; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=0krcWH+oX1VPWcxsC+mPFwkaqla2v62qu06n2N8lzIA=; b=EeMaxtEJ7P2YFB4a5nfCsSu7nV0hTPFuKas94bL1HUwVsxIJv2bb2eINMuC4mO1JH9GKso hded8bNjEZMdI4I4omcyztLHcoDhnvtp/23W0HYAaoL+1zL/7t9Ij8EFq/giQGilWYn8vc Ypet/KFhQ1uD7H7tj0tFx6qXI1TEICM= Received: from mail-qv1-f72.google.com (mail-qv1-f72.google.com [209.85.219.72]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-182-ikDIXzl2MrOwlvJlH5ArGQ-1; Mon, 16 Jun 2025 17:18:05 -0400 X-MC-Unique: ikDIXzl2MrOwlvJlH5ArGQ-1 X-Mimecast-MFC-AGG-ID: ikDIXzl2MrOwlvJlH5ArGQ_1750108685 Received: by mail-qv1-f72.google.com with SMTP id 6a1803df08f44-6fabd295d12so80838426d6.1 for ; Mon, 16 Jun 2025 14:18:05 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1750108684; x=1750713484; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=0krcWH+oX1VPWcxsC+mPFwkaqla2v62qu06n2N8lzIA=; b=uOCmpq8qja6CYXHxWBzPktLXKuqVoKmQlqfw3hYu/7AoHXAiM7WL6C+prXdBTQan+t JFdFOswPyYELEusoaK4DgOcsXpYVEUzkllDT+DgokoqGD88LsznyDu5bQq+20Wd9nnVT NyZlKc4c+wsT9V3Q75eRue3GEfWwSpt7AXo1zt8ec5efG/uCZ3B9FcryX3SOqKRVgd7A 2UuIwPqBJapMjKFzEPCIkrBPTt3CSCH77/uT1/wn7D11tfdHs9nMA67H6EwDYqjQ1CsZ BdzwL4om2gszFxJPSjxdCXZzu1L4c0UDaE+tlxpoeGLdS70DJRBWc3vtDGjmgnEV5xT9 NGAg== X-Forwarded-Encrypted: i=1; AJvYcCX9a37PyxugVGRG32PNM/xmTuRLw+9Rw5CxVgUm1UcllCPbTKM4x8H+LrUdai2b84HiMjif/XyRm4D7@nongnu.org X-Gm-Message-State: AOJu0YwmG5S3gNH6b3Y9dwvd95pcLBIEpJ9xk+W/mL3T6nC/jsSnPnSV XRtmqtsxj5F2XyCDzRqYcJsZA8gnEN1vVWAT3ypTSyJF+kz/LsdO3iZFjRFTYJqzASCY/PSTfIB ylsRbBfbwObGS34aFFvOVRCSwvmGjhR3J3bSZ8AY0yJLiRceAVyonzkda X-Gm-Gg: ASbGncurITV5kOoeMkROJBwSrB77buAzk6A/DvJlw1BUw9jQFUfRlKRUzfZjaHCnn5y cuBanP1IUSKK8Zo8lFUvqDC4wgTv3fLB43QvMND6YgMVdbjwWqJzuf2qSFS8tx8+5Y772kyf1ee Ry51aHqtl7CVIoQHIJGEEXUaWQ/utlF/mxVb13UOggH/s/TMg0Wj2kzGXCKA3GLXuBl1ZDAWoRs ciBhG6n7m5/yOxRYT+otSf0/3n3uqhjdkRfU+hn+9YgOSx+OrfawXREec0XMavrRP5bga9fQ2yh JsYBvcmkwhLNuw== X-Received: by 2002:a05:6214:4a06:b0:6fb:f10:60e with SMTP id 6a1803df08f44-6fb4779a23dmr188133786d6.40.1750108684643; Mon, 16 Jun 2025 14:18:04 -0700 (PDT) X-Google-Smtp-Source: AGHT+IE+7jv0HQYzV3711aI6P/V275dMFO3cJtzMATkmktGjjbfK9w1gUlxgSRFnlJv062lyLQAEOA== X-Received: by 2002:a05:6214:4a06:b0:6fb:f10:60e with SMTP id 6a1803df08f44-6fb4779a23dmr188133346d6.40.1750108684324; Mon, 16 Jun 2025 14:18:04 -0700 (PDT) Received: from x1.local ([85.131.185.92]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-6fb35b20f08sm56156146d6.22.2025.06.16.14.18.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 16 Jun 2025 14:18:03 -0700 (PDT) Date: Mon, 16 Jun 2025 17:18:00 -0400 From: Peter Xu To: "Chaney, Ben" Cc: David Hildenbrand , "Michael S. Tsirkin" , "yury-kotov@yandex-team.ru" , "dgilbert@redhat.com" , "beata.michalska@linaro.org" , "richard.henderson@linaro.org" , "alex.bennee@linaro.org" , "peter.maydell@linaro.org" , "junyan.he@intel.com" , "imammedo@redhat.com" , "qemu-devel@nongnu.org" , "pbonzini@redhat.com" , "philmd@linaro.org" , "xiaoguangrong.eric@gmail.com" , "Tottenham, Max" , "Hunt, Joshua" , "Glasgall, Anna" , "qemu-stable@nongnu.org" Subject: Re: [Patch v2] Don't sync volatile memory Message-ID: References: <1CC43F59-336F-4A12-84AD-DB89E0A17A95@akamai.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <1CC43F59-336F-4A12-84AD-DB89E0A17A95@akamai.com> Received-SPF: pass client-ip=170.10.133.124; envelope-from=peterx@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -39 X-Spam_score: -4.0 X-Spam_bar: ---- X-Spam_report: (-4.0 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1.892, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Mon, Jun 16, 2025 at 08:56:50PM +0000, Chaney, Ben wrote: > Not all pmem regions are backed by non-volatile memory. Syncing volatile > memory provides no benefit, but can cause performance issues is some > cases. Only sync memory that is marked as non-volatile. > > Signed-off-by: Ben Chaney > Fixes: bd108a44bc29 (migration: ram: Switch to ram block writeback) I've queued it with an update on the subject and commit message, as following: migration: Don't sync volatile memory after migration completes Syncing volatile memory provides no benefit, instead it can cause performance issues in some cases. Only sync memory that is marked as non-volatile after migration completes on destination. Thanks, > --- > migration/ram.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/migration/ram.c b/migration/ram.c > index d26dbd37c4..e857b579d6 100644 > --- a/migration/ram.c > +++ b/migration/ram.c > @@ -3672,7 +3672,9 @@ static int ram_load_cleanup(void *opaque) > RAMBlock *rb; > > RAMBLOCK_FOREACH_NOT_IGNORED(rb) { > - qemu_ram_block_writeback(rb); > + if (memory_region_is_nonvolatile(rb->mr)) { > + qemu_ram_block_writeback(rb); > + } > } > > xbzrle_load_cleanup(); > -- > 2.40.1 > -- Peter Xu