From d963ab0f15fb0797ddd65b2653f3d65c2d7a08ec Mon Sep 17 00:00:00 2001 From: John Stultz Date: Sat, 21 Nov 2020 23:50:02 +0000 Subject: dma-buf: system_heap: Allocate higher order pages if available MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit While the system heap can return non-contiguous pages, try to allocate larger order pages if possible. This will allow slight performance gains and make implementing page pooling easier. Cc: Sumit Semwal Cc: Liam Mark Cc: Laura Abbott Cc: Brian Starkey Cc: Hridya Valsaraju Cc: Suren Baghdasaryan Cc: Sandeep Patil Cc: Daniel Mentz Cc: Chris Goldsworthy Cc: Ørjan Eide Cc: Robin Murphy Cc: Ezequiel Garcia Cc: Simon Ser Cc: James Jones Cc: linux-media@vger.kernel.org Cc: dri-devel@lists.freedesktop.org Reviewed-by: Brian Starkey Signed-off-by: John Stultz Signed-off-by: Sumit Semwal Link: https://patchwork.freedesktop.org/patch/msgid/20201121235002.69945-6-john.stultz@linaro.org --- drivers/dma-buf/heaps/system_heap.c | 89 +++++++++++++++++++++++++++++-------- 1 file changed, 71 insertions(+), 18 deletions(-) (limited to 'drivers/dma-buf') diff --git a/drivers/dma-buf/heaps/system_heap.c b/drivers/dma-buf/heaps/system_heap.c index 32b17a5c8079..17e0e9a68baf 100644 --- a/drivers/dma-buf/heaps/system_heap.c +++ b/drivers/dma-buf/heaps/system_heap.c @@ -40,6 +40,20 @@ struct dma_heap_attachment { bool mapped; }; +#define HIGH_ORDER_GFP (((GFP_HIGHUSER | __GFP_ZERO | __GFP_NOWARN \ + | __GFP_NORETRY) & ~__GFP_RECLAIM) \ + | __GFP_COMP) +#define LOW_ORDER_GFP (GFP_HIGHUSER | __GFP_ZERO | __GFP_COMP) +static gfp_t order_flags[] = {HIGH_ORDER_GFP, LOW_ORDER_GFP, LOW_ORDER_GFP}; +/* + * The selection of the orders used for allocation (1MB, 64K, 4K) is designed + * to match with the sizes often found in IOMMUs. Using order 4 pages instead + * of order 0 pages can significantly improve the performance of many IOMMUs + * by reducing TLB pressure and time spent updating page tables. + */ +static const unsigned int orders[] = {8, 4, 0}; +#define NUM_ORDERS ARRAY_SIZE(orders) + static struct sg_table *dup_sg_table(struct sg_table *table) { struct sg_table *new_table; @@ -275,8 +289,11 @@ static void system_heap_dma_buf_release(struct dma_buf *dmabuf) int i; table = &buffer->sg_table; - for_each_sgtable_sg(table, sg, i) - __free_page(sg_page(sg)); + for_each_sg(table->sgl, sg, table->nents, i) { + struct page *page = sg_page(sg); + + __free_pages(page, compound_order(page)); + } sg_free_table(table); kfree(buffer); } @@ -294,6 +311,26 @@ static const struct dma_buf_ops system_heap_buf_ops = { .release = system_heap_dma_buf_release, }; +static struct page *alloc_largest_available(unsigned long size, + unsigned int max_order) +{ + struct page *page; + int i; + + for (i = 0; i < NUM_ORDERS; i++) { + if (size < (PAGE_SIZE << orders[i])) + continue; + if (max_order < orders[i]) + continue; + + page = alloc_pages(order_flags[i], orders[i]); + if (!page) + continue; + return page; + } + return NULL; +} + static int system_heap_allocate(struct dma_heap *heap, unsigned long len, unsigned long fd_flags, @@ -301,11 +338,13 @@ static int system_heap_allocate(struct dma_heap *heap, { struct system_heap_buffer *buffer; DEFINE_DMA_BUF_EXPORT_INFO(exp_info); + unsigned long size_remaining = len; + unsigned int max_order = orders[0]; struct dma_buf *dmabuf; struct sg_table *table; struct scatterlist *sg; - pgoff_t pagecount; - pgoff_t pg; + struct list_head pages; + struct page *page, *tmp_page; int i, ret = -ENOMEM; buffer = kzalloc(sizeof(*buffer), GFP_KERNEL); @@ -317,25 +356,35 @@ static int system_heap_allocate(struct dma_heap *heap, buffer->heap = heap; buffer->len = len; - table = &buffer->sg_table; - pagecount = len / PAGE_SIZE; - if (sg_alloc_table(table, pagecount, GFP_KERNEL)) - goto free_buffer; - - sg = table->sgl; - for (pg = 0; pg < pagecount; pg++) { - struct page *page; + INIT_LIST_HEAD(&pages); + i = 0; + while (size_remaining > 0) { /* * Avoid trying to allocate memory if the process * has been killed by SIGKILL */ if (fatal_signal_pending(current)) - goto free_pages; - page = alloc_page(GFP_KERNEL | __GFP_ZERO); + goto free_buffer; + + page = alloc_largest_available(size_remaining, max_order); if (!page) - goto free_pages; + goto free_buffer; + + list_add_tail(&page->lru, &pages); + size_remaining -= page_size(page); + max_order = compound_order(page); + i++; + } + + table = &buffer->sg_table; + if (sg_alloc_table(table, i, GFP_KERNEL)) + goto free_buffer; + + sg = table->sgl; + list_for_each_entry_safe(page, tmp_page, &pages, lru) { sg_set_page(sg, page, page_size(page), 0); sg = sg_next(sg); + list_del(&page->lru); } /* create the dmabuf */ @@ -355,14 +404,18 @@ static int system_heap_allocate(struct dma_heap *heap, /* just return, as put will call release and that will free */ return ret; } - return ret; free_pages: - for_each_sgtable_sg(table, sg, i) - __free_page(sg_page(sg)); + for_each_sgtable_sg(table, sg, i) { + struct page *p = sg_page(sg); + + __free_pages(p, compound_order(p)); + } sg_free_table(table); free_buffer: + list_for_each_entry_safe(page, tmp_page, &pages, lru) + __free_pages(page, compound_order(page)); kfree(buffer); return ret; -- cgit v1.2.3