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=-8.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, 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=unavailable 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 7823CC43461 for ; Wed, 16 Sep 2020 20:16:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2812120936 for ; Wed, 16 Sep 2020 20:16:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="Oh9ULta1" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727958AbgIPUQA (ORCPT ); Wed, 16 Sep 2020 16:16:00 -0400 Received: from userp2120.oracle.com ([156.151.31.85]:42066 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726921AbgIPRb3 (ORCPT ); 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Wed, 16 Sep 2020 17:31:05 +0000 Received: from pps.filterd (userp3020.oracle.com [127.0.0.1]) by userp3020.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 08GHTs5J134351; Wed, 16 Sep 2020 17:31:04 GMT Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by userp3020.oracle.com with ESMTP id 33hm337mvg-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 16 Sep 2020 17:31:04 +0000 Received: from abhmp0006.oracle.com (abhmp0006.oracle.com [141.146.116.12]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id 08GHV0OP017867; Wed, 16 Sep 2020 17:31:00 GMT Received: from [192.168.2.112] (/50.38.35.18) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 16 Sep 2020 17:31:00 +0000 Subject: Re: [RFC PATCH] cma: make number of CMA areas dynamic, remove CONFIG_CMA_AREAS To: Christoph Hellwig Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mips@vger.kernel.org, Roman Gushchin , Barry Song , Joonsoo Kim , Rik van Riel , Aslan Bakirov , Michal Hocko , Andrew Morton References: <20200903030204.253433-1-mike.kravetz@oracle.com> <20200916043207.GA713@infradead.org> From: Mike Kravetz Message-ID: <7e730a74-3a9d-a18c-3f6a-f7bb206298d5@oracle.com> Date: Wed, 16 Sep 2020 10:30:57 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 MIME-Version: 1.0 In-Reply-To: <20200916043207.GA713@infradead.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9746 signatures=668679 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 bulkscore=0 mlxlogscore=999 malwarescore=0 mlxscore=0 phishscore=0 adultscore=0 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2009160122 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9746 signatures=668679 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 phishscore=0 impostorscore=0 priorityscore=1501 malwarescore=0 suspectscore=0 mlxlogscore=999 clxscore=1011 adultscore=0 lowpriorityscore=0 spamscore=0 mlxscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2009160122 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 9/15/20 9:32 PM, Christoph Hellwig wrote: > On Wed, Sep 02, 2020 at 08:02:04PM -0700, Mike Kravetz wrote: >> --- a/arch/arm/mm/dma-mapping.c >> +++ b/arch/arm/mm/dma-mapping.c >> @@ -383,25 +383,34 @@ postcore_initcall(atomic_pool_init); >> struct dma_contig_early_reserve { >> phys_addr_t base; >> unsigned long size; >> + struct list_head areas; >> }; >> >> +static __initdata LIST_HEAD(dma_mmu_remap_areas); >> >> void __init dma_contiguous_early_fixup(phys_addr_t base, unsigned long size) >> { >> + struct dma_contig_early_reserve *d; >> + >> + d = memblock_alloc(sizeof(struct dma_contig_early_reserve), >> + sizeof(void *)); >> + if (!d) { >> + pr_err("Unable to allocate dma_contig_early_reserve struct!\n"); >> + return; >> + } >> + >> + d->base = base; >> + d->size = size; >> + list_add_tail(&d->areas, &dma_mmu_remap_areas); >> } > > I wonder if struct cma should grow a flags or type field, so that the > arm code can simply use cma_for_each_area to iterate the CMA areas for > the DMA fixup, and we can remove the extra list and the magic hook. I will look into a way of doing that. > >> +/* modify here */ >> +LIST_HEAD(cma_areas); > > What does this comment mean? Sorry, that might have been a note to myself that was accidentally left. > >> +static unsigned int cma_area_count; > > It seems this is only used to provide a default name for the CMA > areas, but all areas actually provide a name, so I think we can drop > the default naming and the cma_area_count variable entirely. > Seems reasonable. We can change behavior to require a name. >> if (!size || !memblock_is_region_reserved(base, size)) >> return -EINVAL; >> >> + >> /* ensure minimal alignment required by mm core */ > > This adds a spurious empty line. yes, my bad. >> static int __init cma_debugfs_init(void) >> { >> struct dentry *cma_debugfs_root; >> - int i; >> + struct cma *c; >> >> cma_debugfs_root = debugfs_create_dir("cma", NULL); >> >> - for (i = 0; i < cma_area_count; i++) >> - cma_debugfs_add_one(&cma_areas[i], cma_debugfs_root); >> + list_for_each_entry(c, &cma_areas, areas) >> + cma_debugfs_add_one(c, cma_debugfs_root); > > I think this should use cma_for_each_area, that way cma_areas can be > keep static in cma.c. Yes, will provide a cma_for_each_area routine. -- Mike Kravetz