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 X-Spam-Level: X-Spam-Status: No, score=-11.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, NICE_REPLY_A,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id ECE3DC4363A for ; Tue, 20 Oct 2020 19:59:48 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 1591A22200 for ; Tue, 20 Oct 2020 19:59:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Eb5gbbFT" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1591A22200 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:35782 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kUxnO-0001o4-QX for qemu-devel@archiver.kernel.org; Tue, 20 Oct 2020 15:59:46 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:47438) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kUxmm-0001Os-TR for qemu-devel@nongnu.org; Tue, 20 Oct 2020 15:59:10 -0400 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:22105) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kUxmh-0003gW-NP for qemu-devel@nongnu.org; Tue, 20 Oct 2020 15:59:06 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1603223941; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=M1Upd50WXE8WYFEKHelvRB1UW3wtZcDDITW23fb8myc=; b=Eb5gbbFTDzbiDGh+elCBOzdU68ZAGdzdmyjv/K4S4byoBJUPv+kkYxddq7BFv//ZCoCTRC cwc1d7ZAdGJOHAxnfrxwDUv7gSahM79GiUWNnmklyFj9wqMQTc11ZAh/Yp4prKtq4Qvon5 dgfvnQRwB27I2Zl1B5d94EfIspZo1f4= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-352-SJ8hzu4wOH2QMPyEMJNcIw-1; Tue, 20 Oct 2020 15:58:57 -0400 X-MC-Unique: SJ8hzu4wOH2QMPyEMJNcIw-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 3D7631084C8A; Tue, 20 Oct 2020 19:58:56 +0000 (UTC) Received: from [10.36.114.141] (ovpn-114-141.ams2.redhat.com [10.36.114.141]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9CC295D9EF; Tue, 20 Oct 2020 19:58:35 +0000 (UTC) Subject: Re: [PATCH PROTOTYPE 4/6] memory: Extend ram_block_discard_(require|disable) by two discard types To: Peter Xu References: <20200924160423.106747-1-david@redhat.com> <20200924160423.106747-5-david@redhat.com> <20201020191706.GB200400@xz-x1> From: David Hildenbrand Organization: Red Hat GmbH Message-ID: Date: Tue, 20 Oct 2020 21:58:34 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.3.1 MIME-Version: 1.0 In-Reply-To: <20201020191706.GB200400@xz-x1> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=david@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=63.128.21.124; envelope-from=david@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/10/20 01:15:43 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=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: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Pankaj Gupta , "Michael S. Tsirkin" , qemu-devel@nongnu.org, Luiz Capitulino , Auger Eric , Alex Williamson , Wei Yang , Igor Mammedov , Paolo Bonzini , "Dr . David Alan Gilbert" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 20.10.20 21:17, Peter Xu wrote: > On Thu, Sep 24, 2020 at 06:04:21PM +0200, David Hildenbrand wrote: >> We want to separate the two cases whereby >> - balloning drivers do random discards on random guest memory (e.g., >> virtio-balloon) - uncoordinated discards >> - paravirtualized memory devices do discards in well-known granularity, >> and always know which block is currently accessible or inaccessible by >> a guest. - coordinated discards >> >> This will be required to get virtio_mem + vfio running - vfio still >> wants to block random memory ballooning. >> >> Cc: Paolo Bonzini >> Cc: "Michael S. Tsirkin" >> Cc: Alex Williamson >> Cc: Wei Yang >> Cc: Dr. David Alan Gilbert >> Cc: Igor Mammedov >> Cc: Pankaj Gupta >> Cc: Peter Xu >> Signed-off-by: David Hildenbrand >> --- >> exec.c | 109 ++++++++++++++++++++++++++++++++++-------- >> include/exec/memory.h | 36 ++++++++++++-- >> 2 files changed, 121 insertions(+), 24 deletions(-) >> >> diff --git a/exec.c b/exec.c >> index e34b602bdf..83098e9230 100644 >> --- a/exec.c >> +++ b/exec.c >> @@ -4098,52 +4098,121 @@ void mtree_print_dispatch(AddressSpaceDispatch *d, MemoryRegion *root) >> * If positive, discarding RAM is disabled. If negative, discarding RAM is >> * required to work and cannot be disabled. >> */ >> -static int ram_block_discard_disabled; >> +static int uncoordinated_discard_disabled; >> +static int coordinated_discard_disabled; > > Instead of duplicating the codes, how about start to make it an array? > > Btw, iiuc these flags do not need atomic operations at all, because all callers > should be with BQL and called majorly during machine start/reset. Even not, I > think we can also use a mutex, maybe it could make things simpler. No strong > opinion, though. > I remember there were some !BQL users (but I might be confusing it with postcopy code that once used to inhibit the balloon without BQL). Will double-check. Simplifying it is certainly a good idea. (we want to be able to check from virtio-balloon code repeatedly without taking a mutex over and over again :) ) Thanks! -- Thanks, David / dhildenb