On Thu, Jul 25, 2019 at 07:31:05PM +0200, Dafna Hirschfeld wrote: > 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 This probably should be a fix: https://lkml.org/lkml/2019/7/25/1432 I also sent it to you. Would it be possible for you to test it? Thanks Nicolin > > Dafna > > > > > > > > > > > On Fri, 24 May 2019 at 01:08, Nicolin Chen <nicoleotsuka@xxxxxxxxx> 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 <hch@xxxxxx> > > > > > > > Signed-off-by: Nicolin Chen <nicoleotsuka@xxxxxxxxx> > > > > --- > > > > 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 > > > >
