From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3rlCsf4XX1zDr35 for ; Thu, 7 Jul 2016 07:03:50 +1000 (AEST) Received: from pps.filterd (m0098419.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.11/8.16.0.11) with SMTP id u66KrphQ077266 for ; Wed, 6 Jul 2016 17:03:47 -0400 Received: from e24smtp03.br.ibm.com (e24smtp03.br.ibm.com [32.104.18.24]) by mx0b-001b2d01.pphosted.com with ESMTP id 2415xm827d-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Wed, 06 Jul 2016 17:03:47 -0400 Received: from localhost by e24smtp03.br.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 6 Jul 2016 18:03:45 -0300 Received: from d24relay02.br.ibm.com (d24relay02.br.ibm.com [9.13.184.26]) by d24dlp02.br.ibm.com (Postfix) with ESMTP id 12CF11DC006D for ; Wed, 6 Jul 2016 17:03:34 -0400 (EDT) Received: from d24av01.br.ibm.com (d24av01.br.ibm.com [9.8.31.91]) by d24relay02.br.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id u66L3f9g26411336 for ; Wed, 6 Jul 2016 18:03:41 -0300 Received: from d24av01.br.ibm.com (localhost [127.0.0.1]) by d24av01.br.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id u66L3eqC017284 for ; Wed, 6 Jul 2016 18:03:41 -0300 From: Mauricio Faria de Oliveira To: linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, linuxppc-dev@lists.ozlabs.org Cc: Jonathan Corbet , Andrew Morton , Russell King , Keith Busch , Jens Axboe , Benjamin Herrenschmidt , Michael Ellerman Subject: [PATCH 0/3] dma, nvme, powerpc: introduce and implement DMA_ATTR_NO_WARN Date: Wed, 6 Jul 2016 18:03:30 -0300 Message-Id: <1467839013-22481-1-git-send-email-mauricfo@linux.vnet.ibm.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , This patchset introduces dma_attr DMA_ATTR_NO_WARN (just like __GFP_NOWARN), which tells the DMA-mapping subsystem to supress allocation failure reports. On some architectures allocation failures are reported with error messages to the system logs. Although this can help to identify and debug problems, drivers which handle failures (eg, retry later) have no problems with them, and can actually flood the system logs with error messages that aren't any problem at all, depending on the implementation of the retry mechanism. So, this provides a way for drivers to avoid those error messages on calls where allocation failures are not a problem, and shouldn't bother the logs. - Patch 1/3 introduces and documents the new dma_attr. - Patch 2/3 implements it on the nvme driver (which might repeatedly trip on allocation failures due to high load, flooding system logs with error messages at least on powerpc: "iommu_alloc failed") - Patch 3/3 implements support for it on powerpc arch (where this problem was observed. It's possible to extend support for more archs if the patchset is welcome). Mauricio Faria de Oliveira (3): dma: introduce DMA_ATTR_NO_WARN nvme: implement DMA_ATTR_NO_WARN powerpc: implement DMA_ATTR_NO_WARN Documentation/DMA-attributes.txt | 17 +++++++++++++++++ arch/powerpc/kernel/iommu.c | 4 ++-- drivers/nvme/host/pci.c | 10 ++++++++-- include/linux/dma-attrs.h | 1 + 4 files changed, 28 insertions(+), 4 deletions(-) -- 1.8.3.1