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-rw-r--r--kernel/dma/contiguous.c142
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;