diff options
Diffstat (limited to 'kernel/dma/contiguous.c')
| -rw-r--r-- | kernel/dma/contiguous.c | 142 |
1 files changed, 127 insertions, 15 deletions
diff --git a/kernel/dma/contiguous.c b/kernel/dma/contiguous.c index 0369fd5fda8f..16b95ff12e4d 100644 --- a/kernel/dma/contiguous.c +++ b/kernel/dma/contiguous.c @@ -5,6 +5,34 @@ * Written by: * Marek Szyprowski <m.szyprowski@samsung.com> * Michal Nazarewicz <mina86@mina86.com> + * + * Contiguous Memory Allocator + * + * The Contiguous Memory Allocator (CMA) makes it possible to + * allocate big contiguous chunks of memory after the system has + * booted. + * + * Why is it needed? + * + * Various devices on embedded systems have no scatter-getter and/or + * IO map support and require contiguous blocks of memory to + * operate. They include devices such as cameras, hardware video + * coders, etc. + * + * Such devices often require big memory buffers (a full HD frame + * is, for instance, more then 2 mega pixels large, i.e. more than 6 + * MB of memory), which makes mechanisms such as kmalloc() or + * alloc_page() ineffective. + * + * At the same time, a solution where a big memory region is + * reserved for a device is suboptimal since often more memory is + * reserved then strictly required and, moreover, the memory is + * inaccessible to page system even if device drivers don't use it. + * + * CMA tries to solve this issue by operating on memory regions + * where only movable pages can be allocated from. This way, kernel + * can use the memory for pagecache and when device driver requests + * it, allocated pages can be migrated. */ #define pr_fmt(fmt) "cma: " fmt @@ -16,12 +44,11 @@ #endif #include <asm/page.h> -#include <asm/dma-contiguous.h> #include <linux/memblock.h> #include <linux/err.h> #include <linux/sizes.h> -#include <linux/dma-contiguous.h> +#include <linux/dma-map-ops.h> #include <linux/cma.h> #ifdef CONFIG_CMA_SIZE_MBYTES @@ -69,6 +96,19 @@ static int __init early_cma(char *p) } early_param("cma", early_cma); +#ifdef CONFIG_DMA_PERNUMA_CMA + +static struct cma *dma_contiguous_pernuma_area[MAX_NUMNODES]; +static phys_addr_t pernuma_size_bytes __initdata; + +static int __init early_cma_pernuma(char *p) +{ + pernuma_size_bytes = memparse(p, &p); + return 0; +} +early_param("cma_pernuma", early_cma_pernuma); +#endif + #ifdef CONFIG_CMA_SIZE_PERCENTAGE static phys_addr_t __init __maybe_unused cma_early_percent_memory(void) @@ -87,6 +127,34 @@ static inline __maybe_unused phys_addr_t cma_early_percent_memory(void) #endif +#ifdef CONFIG_DMA_PERNUMA_CMA +void __init dma_pernuma_cma_reserve(void) +{ + int nid; + + if (!pernuma_size_bytes) + return; + + for_each_online_node(nid) { + int ret; + char name[CMA_MAX_NAME]; + struct cma **cma = &dma_contiguous_pernuma_area[nid]; + + snprintf(name, sizeof(name), "pernuma%d", nid); + ret = cma_declare_contiguous_nid(0, pernuma_size_bytes, 0, 0, + 0, false, name, cma, nid); + if (ret) { + pr_warn("%s: reservation failed: err %d, node %d", __func__, + ret, nid); + continue; + } + + pr_debug("%s: reserved %llu MiB on node %d\n", __func__, + (unsigned long long)pernuma_size_bytes / SZ_1M, nid); + } +} +#endif + /** * dma_contiguous_reserve() - reserve area(s) for contiguous memory handling * @limit: End address of the reserved memory (optional, 0 for any). @@ -134,6 +202,11 @@ void __init dma_contiguous_reserve(phys_addr_t limit) } } +void __weak +dma_contiguous_early_fixup(phys_addr_t base, unsigned long size) +{ +} + /** * dma_contiguous_reserve_area() - reserve custom contiguous area * @size: Size of the reserved area (in bytes), @@ -219,23 +292,44 @@ static struct page *cma_alloc_aligned(struct cma *cma, size_t size, gfp_t gfp) * @size: Requested allocation size. * @gfp: Allocation flags. * - * This function allocates contiguous memory buffer for specified device. It - * tries to use device specific contiguous memory area if available, or the - * default global one. + * tries to use device specific contiguous memory area if available, or it + * tries to use per-numa cma, if the allocation fails, it will fallback to + * try default global one. * - * Note that it byapss one-page size of allocations from the global area as - * the addresses within one page are always contiguous, so there is no need - * to waste CMA pages for that kind; it also helps reduce fragmentations. + * Note that it bypass one-page size of allocations from the per-numa and + * global area as the addresses within one page are always contiguous, so + * there is no need to waste CMA pages for that kind; it also helps reduce + * fragmentations. */ struct page *dma_alloc_contiguous(struct device *dev, size_t size, gfp_t gfp) { +#ifdef CONFIG_DMA_PERNUMA_CMA + int nid = dev_to_node(dev); +#endif + /* 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; + +#ifdef CONFIG_DMA_PERNUMA_CMA + if (nid != NUMA_NO_NODE && !(gfp & (GFP_DMA | GFP_DMA32))) { + struct cma *cma = dma_contiguous_pernuma_area[nid]; + struct page *page; + + if (cma) { + page = cma_alloc_aligned(cma, size, gfp); + if (page) + return page; + } + } +#endif + if (!dma_contiguous_default_area) + return NULL; + return cma_alloc_aligned(dma_contiguous_default_area, size, gfp); } @@ -252,9 +346,27 @@ 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) { - if (!cma_release(dev_get_cma_area(dev), page, - PAGE_ALIGN(size) >> PAGE_SHIFT)) - __free_pages(page, get_order(size)); + unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT; + + /* if dev has its own cma, free page from there */ + if (dev->cma_area) { + if (cma_release(dev->cma_area, page, count)) + return; + } else { + /* + * otherwise, page is from either per-numa cma or default cma + */ +#ifdef CONFIG_DMA_PERNUMA_CMA + if (cma_release(dma_contiguous_pernuma_area[page_to_nid(page)], + page, count)) + return; +#endif + if (cma_release(dma_contiguous_default_area, page, count)) + return; + } + + /* not in any cma, free from buddy */ + __free_pages(page, get_order(size)); } /* @@ -270,14 +382,14 @@ void dma_free_contiguous(struct device *dev, struct page *page, size_t size) static int rmem_cma_device_init(struct reserved_mem *rmem, struct device *dev) { - dev_set_cma_area(dev, rmem->priv); + dev->cma_area = rmem->priv; return 0; } static void rmem_cma_device_release(struct reserved_mem *rmem, struct device *dev) { - dev_set_cma_area(dev, NULL); + dev->cma_area = NULL; } static const struct reserved_mem_ops rmem_cma_ops = { @@ -318,7 +430,7 @@ static int __init rmem_cma_setup(struct reserved_mem *rmem) dma_contiguous_early_fixup(rmem->base, rmem->size); if (default_cma) - dma_contiguous_set_default(cma); + dma_contiguous_default_area = cma; rmem->ops = &rmem_cma_ops; rmem->priv = cma; |