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Commit ea1dd125 authored by Park Ju Hyung's avatar Park Ju Hyung Committed by KakatkarAkshay
Browse files

dma_buf: try to use kmem_cache pool for dmabuf allocations 



These get allocated and freed millions of times on this kernel tree.
Use a dedicated kmem_cache pool and avoid costly dynamic memory allocations.

Most allocations' size is:
(sizeof(struct dma_buf) + sizeof(struct reservation_object)).

Put those under kmem_cache pool and distinguish them with dmabuf->from_kmem
flag.

Signed-off-by: default avatarPark Ju Hyung <qkrwngud825@gmail.com>
[@0ctobot: Adapted for 4.19]
Signed-off-by: default avatarAdam W. Willis <return.of.octobot@gmail.com>
Signed-off-by: default avatarLibXZR <xzr467706992@163.com>
parent eccb867f

drivers/dma-buf/dma-buf.c

+24 −3
Original line number Diff line number Diff line
@@ -49,10 +49,15 @@ 
static atomic_long_t name_counter;



static struct kmem_cache *kmem_attach_pool;

static struct kmem_cache *kmem_dma_buf_pool;



void __init init_dma_buf_kmem_pool(void)

{

	kmem_attach_pool = KMEM_CACHE(dma_buf_attachment, SLAB_HWCACHE_ALIGN | SLAB_PANIC);

	kmem_dma_buf_pool = kmem_cache_create("dma_buf",

		(sizeof(struct dma_buf) + sizeof(struct reservation_object)),

		(sizeof(struct dma_buf) + sizeof(struct reservation_object)),

		SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL);

}



static inline int is_dma_buf_file(struct file *);
@@ -81,6 +86,9 @@ static void dmabuf_dent_put(struct dma_buf *dmabuf) 
{

	if (atomic_dec_and_test(&dmabuf->dent_count)) {

		kfree(dmabuf->name);

		if (dmabuf->from_kmem)

			kmem_cache_free(kmem_dma_buf_pool, dmabuf);

		else

			kfree(dmabuf);

	}

}
@@ -597,6 +605,7 @@ struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info) 
	char *bufname;

	int ret;

	long cnt;

	bool from_kmem;



	if (!exp_info->resv)

		alloc_size += sizeof(struct reservation_object);
@@ -624,7 +633,16 @@ struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info) 
		goto err_module;

	}



	from_kmem = (alloc_size ==

		     (sizeof(struct dma_buf) + sizeof(struct reservation_object)));



	if (from_kmem) {

		dmabuf = kmem_cache_zalloc(kmem_dma_buf_pool, GFP_KERNEL);

		dmabuf->from_kmem = true;

	} else {

		dmabuf = kzalloc(alloc_size, GFP_KERNEL);

	}



	if (!dmabuf) {

		ret = -ENOMEM;

		goto err_name;
@@ -672,6 +690,9 @@ struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info) 
	return dmabuf;



err_dmabuf:

	if (from_kmem)

		kmem_cache_free(kmem_dma_buf_pool, dmabuf);

	else

		kfree(dmabuf);

err_name:

	kfree(bufname);

include/linux/dma-buf.h

+2 −0
Original line number Diff line number Diff line
@@ -448,6 +448,8 @@ struct dma_buf { 
	dma_buf_destructor dtor;

	void *dtor_data;

	atomic_t dent_count;



	bool from_kmem;

};



/**