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=-7.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS 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 E2ABFC04EB8 for ; Mon, 10 Dec 2018 17:10:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9E81920821 for ; Mon, 10 Dec 2018 17:10:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="4/1PNNkG" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9E81920821 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=oracle.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728286AbeLJRKt (ORCPT ); Mon, 10 Dec 2018 12:10:49 -0500 Received: from userp2130.oracle.com ([156.151.31.86]:52524 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727356AbeLJRKt (ORCPT ); Mon, 10 Dec 2018 12:10:49 -0500 Received: from pps.filterd (userp2130.oracle.com [127.0.0.1]) by userp2130.oracle.com (8.16.0.22/8.16.0.22) with SMTP id wBAH9OXJ056158; Mon, 10 Dec 2018 17:10:40 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=subject : to : cc : references : from : message-id : date : mime-version : in-reply-to : content-type : content-transfer-encoding; s=corp-2018-07-02; bh=bCcpAt2b0eyjJyWOq9/ML48cnvhQGumT1i6+Jv47mpY=; b=4/1PNNkGfH4PqgfdalDNAmiKE1wQ0H8SD8wvbAXtx+3GmsCeeIeObFqiVuoSRigT62Bq /B6b0th+ltDxmJu4PEed99Oca1UXfeSRwlPCivPKWxtBZL64b1ogOGkyt68cI5I5JH2U hvgijEo6bzu6rGyhNA8ntriSYn+mpg2+toPlP3pvokxastqXYufs2TEOxBl58QGkHUOq J824p9wcaauZfil+FFqtDQUy/PTFt0CVklleKVVgWQVtR7BQe2qOAjrK59vW/NBx8OP9 IGD4u+OJkhzTUSn6XNjJwllTe6sVmtny09zEDZgeXbZ6Vze+Sgvar+k+RdFiHFHLaP3j mg== Received: from aserv0022.oracle.com (aserv0022.oracle.com [141.146.126.234]) by userp2130.oracle.com with ESMTP id 2p85cty8wt-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 10 Dec 2018 17:10:39 +0000 Received: from aserv0121.oracle.com (aserv0121.oracle.com [141.146.126.235]) by aserv0022.oracle.com (8.14.4/8.14.4) with ESMTP id wBAHAc8G029413 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 10 Dec 2018 17:10:39 GMT Received: from abhmp0017.oracle.com (abhmp0017.oracle.com [141.146.116.23]) by aserv0121.oracle.com (8.14.4/8.13.8) with ESMTP id wBAHAcu6015195; Mon, 10 Dec 2018 17:10:38 GMT Received: from [10.211.47.70] (/10.211.47.70) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Mon, 10 Dec 2018 09:10:38 -0800 Subject: Re: [PATCH v2 1/2] swiotlb: add debugfs to track swiotlb buffer usage To: Dongli Zhang , iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org Cc: konrad.wilk@oracle.com, hch@lst.de, m.szyprowski@samsung.com, robin.murphy@arm.com References: <1544402278-8175-1-git-send-email-dongli.zhang@oracle.com> From: Joe Jin Message-ID: <86d48f6d-76d1-0e94-5c61-9b289dcedc5d@oracle.com> Date: Mon, 10 Dec 2018 09:10:37 -0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <1544402278-8175-1-git-send-email-dongli.zhang@oracle.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9103 signatures=668679 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=2 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1812100154 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/9/18 4:37 PM, Dongli Zhang wrote: > The device driver will not be able to do dma operations once swiotlb buffer > is full, either because the driver is using so many IO TLB blocks inflight, > or because there is memory leak issue in device driver. To export the > swiotlb buffer usage via debugfs would help the user estimate the size of > swiotlb buffer to pre-allocate or analyze device driver memory leak issue. > > Signed-off-by: Dongli Zhang Reviewed-by: Joe Jin > --- > Changed since v1: > * init debugfs with late_initcall (suggested by Robin Murphy) > * create debugfs entries with debugfs_create_ulong(suggested by Robin Murphy) > > kernel/dma/swiotlb.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 50 insertions(+) > > diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c > index 045930e..3979c2c 100644 > --- a/kernel/dma/swiotlb.c > +++ b/kernel/dma/swiotlb.c > @@ -35,6 +35,9 @@ > #include > #include > #include > +#ifdef CONFIG_DEBUG_FS > +#include > +#endif > > #include > #include > @@ -73,6 +76,13 @@ static phys_addr_t io_tlb_start, io_tlb_end; > */ > static unsigned long io_tlb_nslabs; > > +#ifdef CONFIG_DEBUG_FS > +/* > + * The number of used IO TLB block > + */ > +static unsigned long io_tlb_used; > +#endif > + > /* > * This is a free list describing the number of free entries available from > * each index > @@ -528,6 +538,9 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, > dev_warn(hwdev, "swiotlb buffer is full (sz: %zd bytes)\n", size); > return SWIOTLB_MAP_ERROR; > found: > +#ifdef CONFIG_DEBUG_FS > + io_tlb_used += nslots; > +#endif > spin_unlock_irqrestore(&io_tlb_lock, flags); > > /* > @@ -588,6 +601,10 @@ void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr, > */ > for (i = index - 1; (OFFSET(i, IO_TLB_SEGSIZE) != IO_TLB_SEGSIZE -1) && io_tlb_list[i]; i--) > io_tlb_list[i] = ++count; > + > +#ifdef CONFIG_DEBUG_FS > + io_tlb_used -= nslots; > +#endif > } > spin_unlock_irqrestore(&io_tlb_lock, flags); > } > @@ -883,3 +900,36 @@ const struct dma_map_ops swiotlb_dma_ops = { > .dma_supported = dma_direct_supported, > }; > EXPORT_SYMBOL(swiotlb_dma_ops); > + > +#ifdef CONFIG_DEBUG_FS > + > +static int __init swiotlb_create_debugfs(void) > +{ > + static struct dentry *d_swiotlb_usage; > + struct dentry *ent; > + > + d_swiotlb_usage = debugfs_create_dir("swiotlb", NULL); > + > + if (!d_swiotlb_usage) > + return -ENOMEM; > + > + ent = debugfs_create_ulong("io_tlb_nslabs", 0400, > + d_swiotlb_usage, &io_tlb_nslabs); > + if (!ent) > + goto fail; > + > + ent = debugfs_create_ulong("io_tlb_used", 0400, > + d_swiotlb_usage, &io_tlb_used); > + if (!ent) > + goto fail; > + > + return 0; > + > +fail: > + debugfs_remove_recursive(d_swiotlb_usage); > + return -ENOMEM; > +} > + > +late_initcall(swiotlb_create_debugfs); > + > +#endif > -- Oracle Joe Jin | Software Development Director ORACLE | Linux and Virtualization 500 Oracle Parkway Redwood City, CA US 94065