gpu: ion: Modify the system heap to try to allocate large/huge pages

On some systems there is a performance benefit to reducing tlb pressure
by minimizing the number of chunks in an allocation.

Signed-off-by: Rebecca Schultz Zavin <rebecca@android.com>
[jstultz: modified patch to apply to staging directory]
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/android/ion/ion_system_heap.c b/drivers/staging/android/ion/ion_system_heap.c
index dceed5b791cfeb3accb5dfcf19048eacde45dba6..98711ce03753e7c44c50ffffd5c87c8f0c4064fd 100644 (file)
--- a/drivers/staging/android/ion/ion_system_heap.c
+++ b/drivers/staging/android/ion/ion_system_heap.c
@@ -14,7 +14,10 @@
  *
  */
 
+#include <asm/page.h>
+#include <linux/dma-mapping.h>
 #include <linux/err.h>
+#include <linux/highmem.h>
 #include <linux/mm.h>
 #include <linux/scatterlist.h>
 #include <linux/slab.h>
@@ -22,6 +25,35 @@
 #include "ion.h"
 #include "ion_priv.h"
 
+struct page_info {
+       struct page *page;
+       unsigned long order;
+       struct list_head list;
+};
+
+static struct page_info *alloc_largest_available(unsigned long size)
+{
+       static unsigned int orders[] = {8, 4, 0};
+       struct page *page;
+       struct page_info *info;
+       int i;
+
+       for (i = 0; i < ARRAY_SIZE(orders); i++) {
+               if (size < (1 << orders[i]) * PAGE_SIZE)
+                       continue;
+               page = alloc_pages(GFP_HIGHUSER | __GFP_ZERO | __GFP_COMP |
+                                  __GFP_NOWARN | __GFP_NORETRY, orders[i]);
+               if (!page)
+                       continue;
+               split_page(page, orders[i]);
+               info = kmap(page);
+               info->page = page;
+               info->order = orders[i];
+               return info;
+       }
+       return NULL;
+}
+
 static int ion_system_heap_allocate(struct ion_heap *heap,
                                     struct ion_buffer *buffer,
                                     unsigned long size, unsigned long align,
@@ -29,30 +61,54 @@ static int ion_system_heap_allocate(struct ion_heap *heap,
 {
        struct sg_table *table;
        struct scatterlist *sg;
-       int i, j;
-       int npages = PAGE_ALIGN(size) / PAGE_SIZE;
+       int ret;
+       struct list_head pages;
+       struct page_info *info, *tmp_info;
+       int i;
+       long size_remaining = PAGE_ALIGN(size);
+
+       INIT_LIST_HEAD(&pages);
+       while (size_remaining > 0) {
+               info = alloc_largest_available(size_remaining);
+               if (!info)
+                       goto err;
+               list_add_tail(&info->list, &pages);
+               size_remaining -= (1 << info->order) * PAGE_SIZE;
+       }
 
        table = kmalloc(sizeof(struct sg_table), GFP_KERNEL);
        if (!table)
-               return -ENOMEM;
-       i = sg_alloc_table(table, npages, GFP_KERNEL);
-       if (i)
-               goto err0;
-       for_each_sg(table->sgl, sg, table->nents, i) {
-               struct page *page;
-               page = alloc_page(GFP_HIGHUSER | __GFP_ZERO);
-               if (!page)
-                       goto err1;
-               sg_set_page(sg, page, PAGE_SIZE, 0);
+               goto err;
+
+       ret = sg_alloc_table(table, PAGE_ALIGN(size) / PAGE_SIZE, GFP_KERNEL);
+       if (ret)
+               goto err1;
+
+       sg = table->sgl;
+       list_for_each_entry_safe(info, tmp_info, &pages, list) {
+               struct page *page = info->page;
+               for (i = 0; i < (1 << info->order); i++) {
+                       sg_set_page(sg, page + i, PAGE_SIZE, 0);
+                       sg = sg_next(sg);
+               }
+               list_del(&info->list);
+               memset(info, 0, sizeof(struct page_info));
+               kunmap(page);
        }
+
+       dma_sync_sg_for_device(NULL, table->sgl, table->nents,
+                              DMA_BIDIRECTIONAL);
+
        buffer->priv_virt = table;
        return 0;
 err1:
-       for_each_sg(table->sgl, sg, i, j)
-               __free_page(sg_page(sg));
-       sg_free_table(table);
-err0:
        kfree(table);
+err:
+       list_for_each_entry(info, &pages, list) {
+               for (i = 0; i < (1 << info->order); i++)
+                       __free_page(info->page + i);
+               kunmap(info->page);
+       }
        return -ENOMEM;
 }
 
@@ -63,7 +119,7 @@ void ion_system_heap_free(struct ion_buffer *buffer)
        struct sg_table *table = buffer->priv_virt;
 
        for_each_sg(table->sgl, sg, table->nents, i)
-               __free_page(sg_page(sg));
+               __free_pages(sg_page(sg), get_order(sg_dma_len(sg)));
        if (buffer->sg_table)
                sg_free_table(buffer->sg_table);
        kfree(buffer->sg_table);
@@ -85,22 +141,29 @@ void *ion_system_heap_map_kernel(struct ion_heap *heap,
                                 struct ion_buffer *buffer)
 {
        struct scatterlist *sg;
-       int i;
+       int i, j;
        void *vaddr;
        pgprot_t pgprot;
        struct sg_table *table = buffer->priv_virt;
-       struct page **pages = kmalloc(sizeof(struct page *) * table->nents,
-                                     GFP_KERNEL);
-
-       for_each_sg(table->sgl, sg, table->nents, i)
-               pages[i] = sg_page(sg);
+       int npages = PAGE_ALIGN(buffer->size) / PAGE_SIZE;
+       struct page **pages = kzalloc(sizeof(struct page *) * npages,
+                                    GFP_KERNEL);
+       struct page **tmp = pages;
 
        if (buffer->flags & ION_FLAG_CACHED)
                pgprot = PAGE_KERNEL;
        else
                pgprot = pgprot_writecombine(PAGE_KERNEL);
 
-       vaddr = vmap(pages, table->nents, VM_MAP, pgprot);
+       for_each_sg(table->sgl, sg, table->nents, i) {
+               int npages_this_entry = PAGE_ALIGN(sg_dma_len(sg)) / PAGE_SIZE;
+               struct page *page = sg_page(sg);
+               BUG_ON(i >= npages);
+               for (j = 0; j < npages_this_entry; j++) {
+                       *(tmp++) = page++;
+               }
+       }
+       vaddr = vmap(pages, npages, VM_MAP, pgprot);
        kfree(pages);
 
        return vaddr;
@@ -126,8 +189,9 @@ int ion_system_heap_map_user(struct ion_heap *heap, struct ion_buffer *buffer,
                        offset--;
                        continue;
                }
-               vm_insert_page(vma, addr, sg_page(sg));
-               addr += PAGE_SIZE;
+               remap_pfn_range(vma, addr, page_to_pfn(sg_page(sg)),
+                               sg_dma_len(sg), vma->vm_page_prot);
+               addr += sg_dma_len(sg);
        }
        return 0;
 }