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=-7.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,URIBL_SBL,URIBL_SBL_A,USER_AGENT_SANE_2 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 13F78C76190 for ; Thu, 25 Jul 2019 17:31:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D1C4721951 for ; Thu, 25 Jul 2019 17:31:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729934AbfGYRbM (ORCPT ); Thu, 25 Jul 2019 13:31:12 -0400 Received: from bhuna.collabora.co.uk ([46.235.227.227]:46532 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726547AbfGYRbM (ORCPT ); Thu, 25 Jul 2019 13:31:12 -0400 Received: from [IPv6:2a02:810a:113f:a6c2::355a] (unknown [IPv6:2a02:810a:113f:a6c2::355a]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: dafna) by bhuna.collabora.co.uk (Postfix) with ESMTPSA id CF5E128BC07; Thu, 25 Jul 2019 18:31:07 +0100 (BST) Message-ID: <1564075865.2339.6.camel@collabora.com> Subject: Re: [PATCH v3 1/2] dma-contiguous: Abstract dma_{alloc,free}_contiguous() From: Dafna Hirschfeld To: Nicolin Chen , Ezequiel Garcia Cc: hch@lst.de, robin.murphy@arm.com, Marek Szyprowski , vdumpa@nvidia.com, Russell King , Catalin Marinas , Will Deacon , chris@zankel.net, jcmvbkbc@gmail.com, joro@8bytes.org, David Woodhouse , Tony Lindgren , Andrew Morton , sfr@canb.auug.org.au, treding@nvidia.com, keescook@chromium.org, iamjoonsoo.kim@lge.com, wsa+renesas@sang-engineering.com, linux-arm-kernel , Linux Kernel Mailing List , linux-xtensa@linux-xtensa.org, iommu@lists.linux-foundation.org, dann.frazier@canonical.com, linux-media@vger.kernel.org, hans.verkuil@cisco.com Date: Thu, 25 Jul 2019 19:31:05 +0200 In-Reply-To: <20190725165015.GA31961@Asurada-Nvidia.nvidia.com> References: <20190524040633.16854-1-nicoleotsuka@gmail.com> <20190524040633.16854-2-nicoleotsuka@gmail.com> <20190725165015.GA31961@Asurada-Nvidia.nvidia.com> Organization: Collabora Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.22.6-1+deb9u2 Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2019-07-25 at 09:50 -0700, Nicolin Chen wrote: > On Thu, Jul 25, 2019 at 01:06:42PM -0300, Ezequiel Garcia wrote: > > I can't find a way to forward-redirect from Gmail, so I'm Ccing Dafna > > who found a regression caused by this commit. Dafna, can you give all > > the details, including the log and how you are reproducing it? > > I saw the conversation there. Sorry for not replying yet. > May we discuss there since there are full logs available? > > Thanks > Nicolin > Hi, I compiled vivid as built-in into the kernel (not as a separate module) for nitrogen8m device (imx8) and set it to use contig dma for mem_ops by adding the kernel param vivid.allocators=1,1,... I use this devicetree patch for the dtb file: https://lkml.org/lkml/2019/7/24/789. Although it should be the same on any Aarch64 platform. Then, on the board I run the command: v4l2-ctl -d3 -v width=2592,height=1944,pixelformat=UYVY,bytesperline=5184 --stream-mmap --stream-to video.UYVY In every run there is a different crash. Here is one of them: https://pastebin.com/xXgbXMAN Dafna > > > > > > > > On Fri, 24 May 2019 at 01:08, Nicolin Chen wrote: > > > > > > Both dma_alloc_from_contiguous() and dma_release_from_contiguous() > > > are very simply implemented, but requiring callers to pass certain > > > parameters like count and align, and taking a boolean parameter to > > > check __GFP_NOWARN in the allocation flags. So every function call > > > duplicates similar work: > > >   /* A piece of example */ > > >   unsigned long order = get_order(size); > > >   size_t count = size >> PAGE_SHIFT; > > >   page = dma_alloc_from_contiguous(dev, count, order, gfp & __GFP_NOWARN); > > >   [...] > > >   dma_release_from_contiguous(dev, page, size >> PAGE_SHIFT); > > > > > > Additionally, as CMA can be used only in the context which permits > > > sleeping, most of callers do a gfpflags_allow_blocking() check and > > > a corresponding fallback allocation of normal pages upon any false > > > result: > > >   /* A piece of example */ > > >   if (gfpflags_allow_blocking(flag)) > > >       page = dma_alloc_from_contiguous(); > > >   if (!page) > > >       page = alloc_pages(); > > >   [...] > > >   if (!dma_release_from_contiguous(dev, page, count)) > > >       __free_pages(page, get_order(size)); > > > > > > So this patch simplifies those function calls by abstracting these > > > operations into the two new functions: dma_{alloc,free}_contiguous. > > > > > > As some callers of dma_{alloc,release}_from_contiguous() might be > > > complicated, this patch just implements these two new functions to > > > kernel/dma/direct.c only as an initial step. > > > > > > > > > Suggested-by: Christoph Hellwig > > > > > > Signed-off-by: Nicolin Chen > > > --- > > > Changelog > > > v2->v3: > > >  * Added missing "static inline" in header file to fix build error. > > > v1->v2: > > >  * Added new functions beside the old ones so we can replace callers > > >    one by one later. > > >  * Applied new functions to dma/direct.c only, because it's the best > > >    example caller to apply and should be safe with the new functions. > > > > > >  include/linux/dma-contiguous.h | 11 ++++++++ > > >  kernel/dma/contiguous.c        | 48 ++++++++++++++++++++++++++++++++++ > > >  kernel/dma/direct.c            | 24 +++-------------- > > >  3 files changed, 63 insertions(+), 20 deletions(-) > > > > > > diff --git a/include/linux/dma-contiguous.h b/include/linux/dma-contiguous.h > > > index f247e8aa5e3d..00a370c1c140 100644 > > > --- a/include/linux/dma-contiguous.h > > > +++ b/include/linux/dma-contiguous.h > > > @@ -115,6 +115,8 @@ struct page *dma_alloc_from_contiguous(struct device *dev, size_t count, > > >                                        unsigned int order, bool no_warn); > > >  bool dma_release_from_contiguous(struct device *dev, struct page *pages, > > >                                  int count); > > > +struct page *dma_alloc_contiguous(struct device *dev, size_t size, gfp_t gfp); > > > +void dma_free_contiguous(struct device *dev, struct page *page, size_t size); > > > > > >  #else > > > > > > @@ -157,6 +159,15 @@ bool dma_release_from_contiguous(struct device *dev, struct page *pages, > > >         return false; > > >  } > > > > > > +static inline > > > +struct page *dma_alloc_contiguous(struct device *dev, size_t size, gfp_t gfp) > > > +{ > > > +       return NULL; > > > +} > > > + > > > +static inline > > > +void dma_free_contiguous(struct device *dev, struct page *page, size_t size) { } > > > + > > >  #endif > > > > > >  #endif > > > diff --git a/kernel/dma/contiguous.c b/kernel/dma/contiguous.c > > > index b2a87905846d..21f39a6cb04f 100644 > > > --- a/kernel/dma/contiguous.c > > > +++ b/kernel/dma/contiguous.c > > > @@ -214,6 +214,54 @@ bool dma_release_from_contiguous(struct device *dev, struct page *pages, > > >         return cma_release(dev_get_cma_area(dev), pages, count); > > >  } > > > > > > +/** > > > + * dma_alloc_contiguous() - allocate contiguous pages > > > + * @dev:   Pointer to device for which the allocation is performed. > > > + * @size:  Requested allocation size. > > > + * @gfp:   Allocation flags. > > > + * > > > + * This function allocates contiguous memory buffer for specified device. It > > > + * first tries to use device specific contiguous memory area if available or > > > + * the default global one, then tries a fallback allocation of normal pages. > > > + */ > > > +struct page *dma_alloc_contiguous(struct device *dev, size_t size, gfp_t gfp) > > > +{ > > > +       int node = dev ? dev_to_node(dev) : NUMA_NO_NODE; > > > +       size_t count = PAGE_ALIGN(size) >> PAGE_SHIFT; > > > +       size_t align = get_order(PAGE_ALIGN(size)); > > > +       struct cma *cma = dev_get_cma_area(dev); > > > +       struct page *page = NULL; > > > + > > > +       /* CMA can be used only in the context which permits sleeping */ > > > +       if (cma && gfpflags_allow_blocking(gfp)) { > > > +               align = min_t(size_t, align, CONFIG_CMA_ALIGNMENT); > > > +               page = cma_alloc(cma, count, align, gfp & __GFP_NOWARN); > > > +       } > > > + > > > +       /* Fallback allocation of normal pages */ > > > +       if (!page) > > > +               page = alloc_pages_node(node, gfp, align); > > > + > > > +       return page; > > > +} > > > + > > > +/** > > > + * dma_free_contiguous() - release allocated pages > > > + * @dev:   Pointer to device for which the pages were allocated. > > > + * @page:  Pointer to the allocated pages. > > > + * @size:  Size of allocated pages. > > > + * > > > + * This function releases memory allocated by dma_alloc_contiguous(). As the > > > + * cma_release returns false when provided pages do not belong to contiguous > > > + * area and true otherwise, this function then does a fallback __free_pages() > > > + * upon a false-return. > > > + */ > > > +void dma_free_contiguous(struct device *dev, struct page *page, size_t size) > > > +{ > > > +       if (!cma_release(dev_get_cma_area(dev), page, size >> PAGE_SHIFT)) > > > +               __free_pages(page, get_order(size)); > > > +} > > > + > > >  /* > > >   * Support for reserved memory regions defined in device tree > > >   */ > > > diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c > > > index 2c2772e9702a..0816c1e8b05a 100644 > > > --- a/kernel/dma/direct.c > > > +++ b/kernel/dma/direct.c > > > @@ -96,8 +96,6 @@ static bool dma_coherent_ok(struct device *dev, phys_addr_t phys, size_t size) > > >  struct page *__dma_direct_alloc_pages(struct device *dev, size_t size, > > >                 dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs) > > >  { > > > -       unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT; > > > -       int page_order = get_order(size); > > >         struct page *page = NULL; > > >         u64 phys_mask; > > > > > > @@ -109,20 +107,9 @@ struct page *__dma_direct_alloc_pages(struct device *dev, size_t size, > > >         gfp |= __dma_direct_optimal_gfp_mask(dev, dev->coherent_dma_mask, > > >                         &phys_mask); > > >  again: > > > -       /* CMA can be used only in the context which permits sleeping */ > > > -       if (gfpflags_allow_blocking(gfp)) { > > > -               page = dma_alloc_from_contiguous(dev, count, page_order, > > > -                                                gfp & __GFP_NOWARN); > > > -               if (page && !dma_coherent_ok(dev, page_to_phys(page), size)) { > > > -                       dma_release_from_contiguous(dev, page, count); > > > -                       page = NULL; > > > -               } > > > -       } > > > -       if (!page) > > > -               page = alloc_pages_node(dev_to_node(dev), gfp, page_order); > > > - > > > +       page = dma_alloc_contiguous(dev, size, gfp); > > >         if (page && !dma_coherent_ok(dev, page_to_phys(page), size)) { > > > -               __free_pages(page, page_order); > > > +               dma_free_contiguous(dev, page, size); > > >                 page = NULL; > > > > > >                 if (IS_ENABLED(CONFIG_ZONE_DMA32) && > > > @@ -154,7 +141,7 @@ void *dma_direct_alloc_pages(struct device *dev, size_t size, > > >         if (PageHighMem(page)) { > > >                 /* > > >                  * Depending on the cma= arguments and per-arch setup > > > -                * dma_alloc_from_contiguous could return highmem pages. > > > +                * dma_alloc_contiguous could return highmem pages. > > >                  * Without remapping there is no way to return them here, > > >                  * so log an error and fail. > > >                  */ > > > @@ -176,10 +163,7 @@ void *dma_direct_alloc_pages(struct device *dev, size_t size, > > > > > >  void __dma_direct_free_pages(struct device *dev, size_t size, struct page *page) > > >  { > > > -       unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT; > > > - > > > -       if (!dma_release_from_contiguous(dev, page, count)) > > > -               __free_pages(page, get_order(size)); > > > +       dma_free_contiguous(dev, page, size); > > >  } > > > > > >  void dma_direct_free_pages(struct device *dev, size_t size, void *cpu_addr, > > > -- > > > 2.17.1 > > >