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=-5.5 required=3.0 tests=BAYES_00, 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 A4B9DC433F8 for ; Tue, 28 Jul 2020 11:52:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 88DEB206D7 for ; Tue, 28 Jul 2020 11:52:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729173AbgG1Lwh (ORCPT ); Tue, 28 Jul 2020 07:52:37 -0400 Received: from verein.lst.de ([213.95.11.211]:47964 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728504AbgG1Lwg (ORCPT ); Tue, 28 Jul 2020 07:52:36 -0400 Received: by verein.lst.de (Postfix, from userid 2407) id 0344268B05; Tue, 28 Jul 2020 13:52:32 +0200 (CEST) Date: Tue, 28 Jul 2020 13:52:31 +0200 From: Christoph Hellwig To: Barry Song Cc: hch@lst.de, m.szyprowski@samsung.com, robin.murphy@arm.com, will@kernel.org, ganapatrao.kulkarni@cavium.com, catalin.marinas@arm.com, iommu@lists.linux-foundation.org, linuxarm@huawei.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, prime.zeng@hisilicon.com, huangdaode@huawei.com, Jonathan Cameron , Nicolas Saenz Julienne , Steve Capper , Andrew Morton , Mike Rapoport Subject: Re: [PATCH v4 1/2] dma-direct: provide the ability to reserve per-numa CMA Message-ID: <20200728115231.GA793@lst.de> References: <20200723131344.41472-1-song.bao.hua@hisilicon.com> <20200723131344.41472-2-song.bao.hua@hisilicon.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200723131344.41472-2-song.bao.hua@hisilicon.com> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jul 24, 2020 at 01:13:43AM +1200, Barry Song wrote: > +config CMA_PERNUMA_SIZE_MBYTES > + int "Size in Mega Bytes for per-numa CMA areas" > + depends on NUMA > + default 16 if ARM64 > + default 0 > + help > + Defines the size (in MiB) of the per-numa memory area for Contiguous > + Memory Allocator. Every numa node will get a separate CMA with this > + size. If the size of 0 is selected, per-numa CMA is disabled. I'm still not a fan of the config option. You can just hardcode the value in CONFIG_CMDLINE based on the kernel parameter. Also I wonder if a way to expose this in the device tree might be useful, but people more familiar with the device tree and the arm code will have to chime in on that. > struct cma *dma_contiguous_default_area; > +static struct cma *dma_contiguous_pernuma_area[MAX_NUMNODES]; > > /* > * Default global CMA area size can be defined in kernel's .config. > @@ -44,6 +51,8 @@ struct cma *dma_contiguous_default_area; > */ > static const phys_addr_t size_bytes __initconst = > (phys_addr_t)CMA_SIZE_MBYTES * SZ_1M; > +static phys_addr_t pernuma_size_bytes __initdata = > + (phys_addr_t)CMA_SIZE_PERNUMA_MBYTES * SZ_1M; > static phys_addr_t size_cmdline __initdata = -1; > static phys_addr_t base_cmdline __initdata; > static phys_addr_t limit_cmdline __initdata; > @@ -69,6 +78,13 @@ static int __init early_cma(char *p) > } > early_param("cma", early_cma); > > +static int __init early_pernuma_cma(char *p) > +{ > + pernuma_size_bytes = memparse(p, &p); > + return 0; > +} > +early_param("pernuma_cma", early_pernuma_cma); > + > #ifdef CONFIG_CMA_SIZE_PERCENTAGE > > static phys_addr_t __init __maybe_unused cma_early_percent_memory(void) > @@ -96,6 +112,33 @@ static inline __maybe_unused phys_addr_t cma_early_percent_memory(void) > > #endif > > +void __init dma_pernuma_cma_reserve(void) > +{ > + int nid; > + > + if (!pernuma_size_bytes) > + return; > + > + for_each_node_state(nid, N_MEMORY) { > + int ret; > + char name[20]; > + > + snprintf(name, sizeof(name), "pernuma%d", nid); > + ret = cma_declare_contiguous_nid(0, pernuma_size_bytes, 0, 0, > + 0, false, name, > + &dma_contiguous_pernuma_area[nid], > + nid); This adds a > 80 char line. > struct page *dma_alloc_contiguous(struct device *dev, size_t size, gfp_t gfp) > { > + int nid = dev_to_node(dev); > + > /* CMA can be used only in the context which permits sleeping */ > if (!gfpflags_allow_blocking(gfp)) > return NULL; > if (dev->cma_area) > return cma_alloc_aligned(dev->cma_area, size, gfp); > - if (size <= PAGE_SIZE || !dma_contiguous_default_area) > + if (size <= PAGE_SIZE) > return NULL; > + > + if ((nid != NUMA_NO_NODE) && !(gfp & (GFP_DMA | GFP_DMA32))) { No need for the braces around the nid check. > + struct cma *cma = dma_contiguous_pernuma_area[nid]; > + struct page *page; > + > + if (cma) { > + page = cma_alloc_aligned(cma, size, gfp); > + if (page) > + return page; > + } > + } > + > return cma_alloc_aligned(dma_contiguous_default_area, size, gfp); This seems to have lost the dma_contiguous_default_area NULL check. > + /* if dev has its own cma, free page from there */ > + if (dev->cma_area) { > + if (cma_release(dev->cma_area, page, PAGE_ALIGN(size) >> PAGE_SHIFT)) > + return; Another overly long line. > + } else { > + /* > + * otherwise, page is from either per-numa cma or default cma > + */ > + if (cma_release(dma_contiguous_pernuma_area[page_to_nid(page)], > + page, PAGE_ALIGN(size) >> PAGE_SHIFT)) > + return; > + > + if (cma_release(dma_contiguous_default_area, page, > + PAGE_ALIGN(size) >> PAGE_SHIFT)) > + return; > + } I'd introduce a count variable for the value of "PAGE_ALIGN(size) >> PAGE_SHIFT" to clean al lthis up a bit. Also please add a CONFIG_PERCPU_DMA_CMA config variable so that we don't build this code for the vast majority of users that don't need it.