Commit c4d0ac1c authored by Pavel Begunkov's avatar Pavel Begunkov Committed by Jens Axboe
Browse files

io_uring/memmap: optimise single folio regions 



We don't need to vmap if memory is already physically contiguous. There
are two important cases it covers: PAGE_SIZE regions and huge pages.
Use io_check_coalesce_buffer() to get the number of contiguous folios.

Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/d5240af23064a824c29d14d2406f1ae764bf4505.1732886067.git.asml.silence@gmail.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 226ae1b4

io_uring/memmap.c

+22 −7
Original line number Diff line number Diff line
@@ -226,12 +226,31 @@ void io_free_region(struct io_ring_ctx *ctx, struct io_mapped_region *mr) 
	memset(mr, 0, sizeof(*mr));

}



static int io_region_init_ptr(struct io_mapped_region *mr)

{

	struct io_imu_folio_data ifd;

	void *ptr;



	if (io_check_coalesce_buffer(mr->pages, mr->nr_pages, &ifd)) {

		if (ifd.nr_folios == 1) {

			mr->ptr = page_address(mr->pages[0]);

			return 0;

		}

	}

	ptr = vmap(mr->pages, mr->nr_pages, VM_MAP, PAGE_KERNEL);

	if (!ptr)

		return -ENOMEM;



	mr->ptr = ptr;

	mr->flags |= IO_REGION_F_VMAP;

	return 0;

}



int io_create_region(struct io_ring_ctx *ctx, struct io_mapped_region *mr,

		     struct io_uring_region_desc *reg)

{

	struct page **pages;

	int nr_pages, ret;

	void *vptr;

	u64 end;



	if (WARN_ON_ONCE(mr->pages || mr->ptr || mr->nr_pages))
@@ -267,13 +286,9 @@ int io_create_region(struct io_ring_ctx *ctx, struct io_mapped_region *mr, 
	mr->pages = pages;

	mr->flags |= IO_REGION_F_USER_PROVIDED;



	vptr = vmap(pages, nr_pages, VM_MAP, PAGE_KERNEL);

	if (!vptr) {

		ret = -ENOMEM;

	ret = io_region_init_ptr(mr);

	if (ret)

		goto out_free;

	}

	mr->ptr = vptr;

	mr->flags |= IO_REGION_F_VMAP;

	return 0;

out_free:

	io_free_region(ctx, mr);