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=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 2AAB9C3A5A7 for ; Wed, 4 Sep 2019 13:16:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 03E332339D for ; Wed, 4 Sep 2019 13:16:40 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="EPgCnv3/" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730377AbfIDNQj (ORCPT ); Wed, 4 Sep 2019 09:16:39 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:43778 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730188AbfIDNQj (ORCPT ); Wed, 4 Sep 2019 09:16:39 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Transfer-Encoding :Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Sender:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help: List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=Ngepyp17twGTeYQ8Cw2V78KUkItUxdkjHkfPYs5tJiE=; b=EPgCnv3/3HMoDmVsbpFjvbyTDM 0neIHRURrGJEadkGkuEjNUD1pZiPkf4j+wRMTw/4qqa9FCC0XT9d8K1r9moXgys751vncLs835TX4 okmT3e8VY548HAPx1xrCQz/lrTC5V1mAmkfOTGQGOfbqhQvJHmm6t8YFCyRyqgDOdfticjqyeKmgn aprsSCdziDmx/xCEXAIEo1LvYpFjlvJs7xLtZ/FuYxgMBrNCnsIVi2KcbG8dsXBlcgc0Fm5N2Uvmm sf7DBwSRYPg0yaXJ0GPXLkTaNRd3qXnHAsE9h0BSjZmA2UVws5dm6VaOKye6MBJ5Gr8Gc1SMmr+IR xaC9yM/Q==; Received: from hch by bombadil.infradead.org with local (Exim 4.92 #3 (Red Hat Linux)) id 1i5V9K-0000oJ-GN; Wed, 04 Sep 2019 13:16:38 +0000 Date: Wed, 4 Sep 2019 06:16:38 -0700 From: Christoph Hellwig To: Thomas =?iso-8859-1?Q?Hellstr=F6m_=28VMware=29?= Cc: Christoph Hellwig , "linux-kernel@vger.kernel.org" Subject: Re: dma api errors with swiotlb Message-ID: <20190904131638.GA29164@infradead.org> References: <20190904121722.GA15601@infradead.org> <4e21951d-025a-2b3d-14c8-878c6f237525@shipmail.org> <20190904125538.GA30177@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.11.4 (2019-03-13) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Sep 04, 2019 at 03:02:14PM +0200, Thomas Hellström (VMware) wrote: > It looks like it does that, although when we send it, the SWIOTLB error has > already occured and been printed out, and then the sequence starts again. Well, the only way to really find out is to try. We also have a backoff algorithm in the SCSI midlayer, so it should not be much of an inpact. If you care about the warnings they can be disabled using DMA_ATTR_NO_WARN. I have to admit that I'm not even sure the warnings are all that useful, but that's something you need to take up with the swiotlb maintainer.