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dma-buf: system_heap: Allocate higher order pages if available

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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 <sumit.semwal@linaro.org>
Cc: Liam Mark <lmark@codeaurora.org>
Cc: Laura Abbott <labbott@kernel.org>
Cc: Brian Starkey <Brian.Starkey@arm.com>
Cc: Hridya Valsaraju <hridya@google.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Sandeep Patil <sspatil@google.com>
Cc: Daniel Mentz <danielmentz@google.com>
Cc: Chris Goldsworthy <cgoldswo@codeaurora.org>
Cc: Ørjan Eide <orjan.eide@arm.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Ezequiel Garcia <ezequiel@collabora.com>
Cc: Simon Ser <contact@emersion.fr>
Cc: James Jones <jajones@nvidia.com>
Cc: linux-media@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: Brian Starkey <brian.starkey@arm.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20201121235002.69945-6-john.stultz@linaro.org
This commit is contained in:
John Stultz 2020-11-21 23:50:02 +00:00 committed by Sumit Semwal
parent 4c68e499bb
commit d963ab0f15
1 changed files with 71 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

89
drivers/dma-buf/heaps/system_heap.c
View File

@ -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;