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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 712A4C432C3 for ; Fri, 22 Nov 2019 04:38:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4FF5B2068D for ; Fri, 22 Nov 2019 04:38:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726714AbfKVEiP (ORCPT ); Thu, 21 Nov 2019 23:38:15 -0500 Received: from smtprelay0208.hostedemail.com ([216.40.44.208]:57017 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726529AbfKVEiO (ORCPT ); Thu, 21 Nov 2019 23:38:14 -0500 Received: from filter.hostedemail.com (clb03-v110.bra.tucows.net [216.40.38.60]) by smtprelay02.hostedemail.com (Postfix) with ESMTP id 4ADBF5854; Fri, 22 Nov 2019 04:38:13 +0000 (UTC) X-Session-Marker: 6A6F6540706572636865732E636F6D X-HE-Tag: veil65_47a046490b214 X-Filterd-Recvd-Size: 2305 Received: from XPS-9350.home (unknown [47.151.135.224]) (Authenticated sender: joe@perches.com) by omf05.hostedemail.com (Postfix) with ESMTPA; Fri, 22 Nov 2019 04:38:12 +0000 (UTC) Message-ID: <7fd08d481a372ea0b600f95c12166ab54ed5e267.camel@perches.com> Subject: Re: [PATCH v2] iommu/iova: silence warnings under memory pressure From: Joe Perches To: Qian Cai , jroedel@suse.de Cc: baolu.lu@linux.intel.com, dwmw2@infradead.org, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org Date: Thu, 21 Nov 2019 20:37:48 -0800 In-Reply-To: <20191122025510.4319-1-cai@lca.pw> References: <20191122025510.4319-1-cai@lca.pw> Content-Type: text/plain; charset="ISO-8859-1" User-Agent: Evolution 3.34.1-2 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2019-11-21 at 21:55 -0500, Qian Cai wrote: > When running heavy memory pressure workloads, this 5+ old system is > throwing endless warnings below because disk IO is too slow to recover > from swapping. Since the volume from alloc_iova_fast() could be large, > once it calls printk(), it will trigger disk IO (writing to the log > files) and pending softirqs which could cause an infinite loop and make > no progress for days by the ongoimng memory reclaim. This is the counter > part for Intel where the AMD part has already been merged. See the > commit 3d708895325b ("iommu/amd: Silence warnings under memory > pressure"). Since the allocation failure will be reported in > intel_alloc_iova(), so just call printk_ratelimted() there and silence > the one in alloc_iova_mem() to avoid the expensive warn_alloc(). [] > v2: use dev_err_ratelimited() and improve the commit messages. [] > diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c [] > @@ -3401,7 +3401,8 @@ static unsigned long intel_alloc_iova(struct device *dev, > iova_pfn = alloc_iova_fast(&domain->iovad, nrpages, > IOVA_PFN(dma_mask), true); > if (unlikely(!iova_pfn)) { > - dev_err(dev, "Allocating %ld-page iova failed", nrpages); > + dev_err_ratelimited(dev, "Allocating %ld-page iova failed", > + nrpages); Trivia: This should really have a \n termination on the format string dev_err_ratelimited(dev, "Allocating %ld-page iova failed\n",