2021-01-28 06:24:55

by John Stultz

[permalink] [raw]
Subject: [PATCH v3 3/3] dma-buf: system_heap: Add deferred freeing to the system heap

Utilize the deferred free helper library in the system heap.

This provides a nice performance bump and puts the
system heap performance on par with ION.

Cc: Daniel Vetter <[email protected]>
Cc: Sumit Semwal <[email protected]>
Cc: Liam Mark <[email protected]>
Cc: Chris Goldsworthy <[email protected]>
Cc: Laura Abbott <[email protected]>
Cc: Brian Starkey <[email protected]>
Cc: Hridya Valsaraju <[email protected]>
Cc: Suren Baghdasaryan <[email protected]>
Cc: Sandeep Patil <[email protected]>
Cc: Daniel Mentz <[email protected]>
Cc: Ørjan Eide <[email protected]>
Cc: Robin Murphy <[email protected]>
Cc: Ezequiel Garcia <[email protected]>
Cc: Simon Ser <[email protected]>
Cc: James Jones <[email protected]>
Cc: [email protected]
Cc: [email protected]
Signed-off-by: John Stultz <[email protected]>
---
v2:
* Rework deferred-free api to use reason enum as suggested by
Suren Baghdasaryan
---
drivers/dma-buf/heaps/Kconfig | 1 +
drivers/dma-buf/heaps/system_heap.c | 32 ++++++++++++++++++++++-------
2 files changed, 26 insertions(+), 7 deletions(-)

diff --git a/drivers/dma-buf/heaps/Kconfig b/drivers/dma-buf/heaps/Kconfig
index 45c7d277448b..2276420ae905 100644
--- a/drivers/dma-buf/heaps/Kconfig
+++ b/drivers/dma-buf/heaps/Kconfig
@@ -6,6 +6,7 @@ config DMABUF_HEAPS_SYSTEM
depends on DMABUF_HEAPS
select NET
select PAGE_POOL
+ select DMABUF_HEAPS_DEFERRED_FREE
help
Choose this option to enable the system dmabuf heap. The system heap
is backed by pages from the buddy allocator. If in doubt, say Y.
diff --git a/drivers/dma-buf/heaps/system_heap.c b/drivers/dma-buf/heaps/system_heap.c
index 2addb6d832e0..fe122b5eff10 100644
--- a/drivers/dma-buf/heaps/system_heap.c
+++ b/drivers/dma-buf/heaps/system_heap.c
@@ -22,6 +22,8 @@
#include <linux/vmalloc.h>
#include <net/page_pool.h>

+#include "deferred-free-helper.h"
+
static struct dma_heap *sys_heap;

struct system_heap_buffer {
@@ -32,6 +34,7 @@ struct system_heap_buffer {
struct sg_table sg_table;
int vmap_cnt;
void *vaddr;
+ struct deferred_freelist_item deferred_free;
};

struct dma_heap_attachment {
@@ -301,30 +304,45 @@ static int system_heap_zero_buffer(struct system_heap_buffer *buffer)
return ret;
}

-static void system_heap_dma_buf_release(struct dma_buf *dmabuf)
+static void system_heap_buf_free(struct deferred_freelist_item *item,
+ enum df_reason reason)
{
- struct system_heap_buffer *buffer = dmabuf->priv;
+ struct system_heap_buffer *buffer;
struct sg_table *table;
struct scatterlist *sg;
int i, j;

+ buffer = container_of(item, struct system_heap_buffer, deferred_free);
/* Zero the buffer pages before adding back to the pool */
- system_heap_zero_buffer(buffer);
+ if (reason == DF_NORMAL)
+ if (system_heap_zero_buffer(buffer))
+ reason = DF_UNDER_PRESSURE; // On failure, just free

table = &buffer->sg_table;
for_each_sg(table->sgl, sg, table->nents, i) {
struct page *page = sg_page(sg);

- for (j = 0; j < NUM_ORDERS; j++) {
- if (compound_order(page) == orders[j])
- break;
+ if (reason == DF_UNDER_PRESSURE) {
+ __free_pages(page, compound_order(page));
+ } else {
+ for (j = 0; j < NUM_ORDERS; j++) {
+ if (compound_order(page) == orders[j])
+ break;
+ }
+ page_pool_put_full_page(pools[j], page, false);
}
- page_pool_put_full_page(pools[j], page, false);
}
sg_free_table(table);
kfree(buffer);
}

+static void system_heap_dma_buf_release(struct dma_buf *dmabuf)
+{
+ struct system_heap_buffer *buffer = dmabuf->priv;
+
+ deferred_free(&buffer->deferred_free, system_heap_buf_free, buffer->len);
+}
+
static const struct dma_buf_ops system_heap_buf_ops = {
.attach = system_heap_attach,
.detach = system_heap_detach,
--
2.25.1