commit 04c7adb5871a ("dma-buf: system_heap: use larger contiguous mappings instead of per-page mmap") facilitates the use of PTE_CONT. The system_heap allocates pages of order 4 and 8 that meet the alignment requirements for PTE_CONT. enabling PTE_CONT for larger contiguous mappings.
After applying this patch, TLB misses are reduced by approximately 5% when opening the camera on Android systems.
Signed-off-by: gao xu gaoxu2@honor.com --- drivers/dma-buf/heaps/system_heap.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/dma-buf/heaps/system_heap.c b/drivers/dma-buf/heaps/system_heap.c index 4c782fe33..103b06f89 100644 --- a/drivers/dma-buf/heaps/system_heap.c +++ b/drivers/dma-buf/heaps/system_heap.c @@ -202,12 +202,16 @@ static int system_heap_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma) unsigned long n = (sg->length >> PAGE_SHIFT) - pgoff; struct page *page = sg_page(sg) + pgoff; unsigned long size = n << PAGE_SHIFT; + pgprot_t prot = vma->vm_page_prot;
if (addr + size > vma->vm_end) size = vma->vm_end - addr;
+ if (((addr | size) & ~CONT_PTE_MASK) == 0) + prot = __pgprot(pgprot_val(prot) | PTE_CONT); + ret = remap_pfn_range(vma, addr, page_to_pfn(page), - size, vma->vm_page_prot); + size, prot); if (ret) return ret;