diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c index 9e7742f0a102..c704eed63c5d 100644 --- a/arch/arm/mm/dma-mapping.c +++ b/arch/arm/mm/dma-mapping.c @@ -183,6 +183,8 @@ static void * __dma_alloc_remap(struct page *page, size_t size, gfp_t gfp, pgprot_t prot) { struct arm_vmregion *c; + size_t align; + int bit; if (!consistent_pte[0]) { printk(KERN_ERR "%s: not initialised\n", __func__); @@ -190,10 +192,21 @@ __dma_alloc_remap(struct page *page, size_t size, gfp_t gfp, pgprot_t prot) return NULL; } + /* + * Align the virtual region allocation - maximum alignment is + * a section size, minimum is a page size. This helps reduce + * fragmentation of the DMA space, and also prevents allocations + * smaller than a section from crossing a section boundary. + */ + bit = fls(size - 1) + 1; + if (bit > SECTION_SHIFT) + bit = SECTION_SHIFT; + align = 1 << bit; + /* * Allocate a virtual address in the consistent mapping region. */ - c = arm_vmregion_alloc(&consistent_head, size, + c = arm_vmregion_alloc(&consistent_head, align, size, gfp & ~(__GFP_DMA | __GFP_HIGHMEM)); if (c) { pte_t *pte; diff --git a/arch/arm/mm/vmregion.c b/arch/arm/mm/vmregion.c index 19e09bdb1b8a..935993e1b1ef 100644 --- a/arch/arm/mm/vmregion.c +++ b/arch/arm/mm/vmregion.c @@ -35,7 +35,8 @@ */ struct arm_vmregion * -arm_vmregion_alloc(struct arm_vmregion_head *head, size_t size, gfp_t gfp) +arm_vmregion_alloc(struct arm_vmregion_head *head, size_t align, + size_t size, gfp_t gfp) { unsigned long addr = head->vm_start, end = head->vm_end - size; unsigned long flags; @@ -58,7 +59,7 @@ arm_vmregion_alloc(struct arm_vmregion_head *head, size_t size, gfp_t gfp) goto nospc; if ((addr + size) <= c->vm_start) goto found; - addr = c->vm_end; + addr = ALIGN(c->vm_end, align); if (addr > end) goto nospc; } diff --git a/arch/arm/mm/vmregion.h b/arch/arm/mm/vmregion.h index 6b2cdbdf3a85..15e9f044db9f 100644 --- a/arch/arm/mm/vmregion.h +++ b/arch/arm/mm/vmregion.h @@ -21,7 +21,7 @@ struct arm_vmregion { int vm_active; }; -struct arm_vmregion *arm_vmregion_alloc(struct arm_vmregion_head *, size_t, gfp_t); +struct arm_vmregion *arm_vmregion_alloc(struct arm_vmregion_head *, size_t, size_t, gfp_t); struct arm_vmregion *arm_vmregion_find(struct arm_vmregion_head *, unsigned long); struct arm_vmregion *arm_vmregion_find_remove(struct arm_vmregion_head *, unsigned long); void arm_vmregion_free(struct arm_vmregion_head *, struct arm_vmregion *);