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Subject[PATCH 017/115] gpu: ion: Modify the system heap to try to allocate large/huge pages
Date
From: Rebecca Schultz Zavin <rebecca@android.com>

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>
---
drivers/staging/android/ion/ion_system_heap.c | 116 ++++++++++++++++++++------
1 file changed, 90 insertions(+), 26 deletions(-)

diff --git a/drivers/staging/android/ion/ion_system_heap.c b/drivers/staging/android/ion/ion_system_heap.c
index dceed5b..98711ce 100644
--- 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;
}
--
1.8.3.2


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