On Sun, Jun 28, 2020 at 11:12:50PM +1200, Barry Song wrote:
> struct page *dma_alloc_contiguous(struct device *dev, size_t size, gfp_t gfp)
> {
> size_t count = size >> PAGE_SHIFT;
> struct page *page = NULL;
> struct cma *cma = NULL;
> + int nid = dev ? dev_to_node(dev) : NUMA_NO_NODE;
> + bool alloc_from_pernuma = false;
> +
> + if ((count <= 1) && !(dev && dev->cma_area))
> + return NULL;
>
> if (dev && dev->cma_area)
> cma = dev->cma_area;
> - else if (count > 1)
> + else if ((nid != NUMA_NO_NODE) && dma_contiguous_pernuma_area[nid]
> + && !(gfp & (GFP_DMA | GFP_DMA32))) {
> + cma = dma_contiguous_pernuma_area[nid];
> + alloc_from_pernuma = true;
> + } else {
> cma = dma_contiguous_default_area;
> + }
I find the function rather confusing now. What about something
like (this relies on the fact that dev should never be NULL in the
DMA API)
struct page *dma_alloc_contiguous(struct device *dev, size_t size, gfp_t gfp)
{
size_t cma_align = min_t(size_t, get_order(size), CONFIG_CMA_ALIGNMENT);
size_t count = size >> PAGE_SHIFT;
if (gfpflags_allow_blocking(gfp))
return NULL;
gfp &= __GFP_NOWARN;
if (dev->cma_area)
return cma_alloc(dev->cma_area, count, cma_align, gfp);
if (count <= 1)
return NULL;
if (IS_ENABLED(CONFIG_PERNODE_CMA) && !(gfp & (GFP_DMA | GFP_DMA32)) {
int nid = dev_to_node(dev);
struct cma *cma = dma_contiguous_pernuma_area[nid];
struct page *page;
if (cma) {
page = cma_alloc(cma, count, cma_align, gfp);
if (page)
return page;
}
}
return cma_alloc(dma_contiguous_default_area, count, cma_align, gfp);
}
> + /*
> + * otherwise, page is from either per-numa cma or default cma
> + */
> + int nid = page_to_nid(page);
> +
> + if (nid != NUMA_NO_NODE) {
> + if (cma_release(dma_contiguous_pernuma_area[nid], page,
> + PAGE_ALIGN(size) >> PAGE_SHIFT))
> + return;
> + }
> +
> + if (cma_release(dma_contiguous_default_area, page,
How can page_to_nid ever return NUMA_NO_NODE?
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu
