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=-9.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,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 2D1F6C433E0 for ; Wed, 23 Dec 2020 13:41:59 +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 D790F20715 for ; Wed, 23 Dec 2020 13:41:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D790F20715 Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from list by lists.xenproject.org with outflank-mailman.58365.102545 (Exim 4.92) (envelope-from ) id 1ks4Og-0007Gg-1w; Wed, 23 Dec 2020 13:41:46 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 58365.102545; Wed, 23 Dec 2020 13:41:46 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1ks4Of-0007GZ-VL; Wed, 23 Dec 2020 13:41:45 +0000 Received: by outflank-mailman (input) for mailman id 58365; Wed, 23 Dec 2020 13:41:44 +0000 Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1ks4Oe-0007GU-Ft for xen-devel@lists.xenproject.org; Wed, 23 Dec 2020 13:41:44 +0000 Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id 7ffadb67-6490-4775-bd1d-e3bd3c64279b; Wed, 23 Dec 2020 13:41:43 +0000 (UTC) Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id A5606AD45; Wed, 23 Dec 2020 13:41:42 +0000 (UTC) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 7ffadb67-6490-4775-bd1d-e3bd3c64279b X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1608730902; h=from:from:reply-to: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=JyMtVEp3gj3hiB5cHZ50ugknG+GdM6y8lldwRx7V01Q=; b=XvCj9/2FPtTy18Ar2ruseDsjBaT2ulvmIKXN2AheOQK5cAsEBqg4Prhnm30EFhubk+VP5V DHIBBhLIqXqZumoNTYhmNm8TecyjH2oHUjtJdsQcJSz7KR88tetj4IdYWzo9hyX7baeFvS /B5sXpTkH9gaN0OJtV9AXnffLJ4w+ks= Subject: Re: [PATCH v3 5/5] evtchn: don't call Xen consumer callback with per-channel lock held To: Julien Grall , Tamas K Lengyel Cc: Andrew Cooper , George Dunlap , Ian Jackson , Wei Liu , Stefano Stabellini , Tamas K Lengyel , Petre Ovidiu PIRCALABU , Alexandru Isaila , "xen-devel@lists.xenproject.org" References: <9d7a052a-6222-80ff-cbf1-612d4ca50c2a@suse.com> <17c90493-b438-fbc1-ca10-3bc4d89c4e5e@xen.org> <7a768bcd-80c1-d193-8796-7fb6720fa22a@suse.com> <1a8250f5-ea49-ac3a-e992-be7ec40deba9@xen.org> <5862eb24-d894-455a-13ac-61af54f949e7@xen.org> <9ee6016a-d3b3-c847-4775-0e05c8578110@xen.org> From: Jan Beulich Message-ID: <3b339f30-57db-caf6-fd7e-84199f98546f@suse.com> Date: Wed, 23 Dec 2020 14:41:42 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit On 23.12.2020 14:33, Julien Grall wrote: > On 23/12/2020 13:12, Jan Beulich wrote: >> From the input by both of you I still can't >> conclude whether this patch should remain as is in v4, or revert >> back to its v2 version. Please can we get this settled so I can get >> v4 out? > > I haven't had time to investigate the rest of the VM event code to find > other cases where this may happen. I still think there is a bigger > problem in the VM event code, but the maintainer disagrees here. > > At which point, I see limited reason to try to paper over in the common > code. So I would rather ack/merge v2 rather than v3. Since I expect Tamas and/or the Bitdefender folks to be of the opposite opinion, there's still no way out, at least if "rather ack" implies a nak for v3. Personally, if this expectation of mine is correct, I'd prefer to keep the accounting but make it optional (as suggested in a post-commit-message remark). That'll eliminate the overhead you appear to be concerned of, but of course it'll further complicate the logic (albeit just slightly). Jan