Commit 7919292a authored by Pavel Begunkov's avatar Pavel Begunkov Committed by Jens Axboe
Browse files

io_uring/kbuf: remove legacy kbuf bulk allocation 



Legacy provided buffers are slow and discouraged in favour of the ring
variant. Remove the bulk allocation to keep it simpler as we don't care
about performance.

Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/a064d70370e590efed8076e9501ae4cfc20fe0ca.1738724373.git.asml.silence@gmail.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 92a3bac9

io_uring/kbuf.c

+5 −25
Original line number Diff line number Diff line
@@ -501,12 +501,9 @@ int io_provide_buffers_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe 
	return 0;

}



#define IO_BUFFER_ALLOC_BATCH 64



static int io_refill_buffer_cache(struct io_ring_ctx *ctx)

{

	struct io_buffer *bufs[IO_BUFFER_ALLOC_BATCH];

	int allocated;

	struct io_buffer *buf;



	/*

	 * Completions that don't happen inline (eg not under uring_lock) will
@@ -524,27 +521,10 @@ static int io_refill_buffer_cache(struct io_ring_ctx *ctx) 
		spin_unlock(&ctx->completion_lock);

	}



	/*

	 * No free buffers and no completion entries either. Allocate a new

	 * batch of buffer entries and add those to our freelist.

	 */



	allocated = kmem_cache_alloc_bulk(io_buf_cachep, GFP_KERNEL_ACCOUNT,

					  ARRAY_SIZE(bufs), (void **) bufs);

	if (unlikely(!allocated)) {

		/*

		 * Bulk alloc is all-or-nothing. If we fail to get a batch,

		 * retry single alloc to be on the safe side.

		 */

		bufs[0] = kmem_cache_alloc(io_buf_cachep, GFP_KERNEL);

		if (!bufs[0])

	buf = kmem_cache_alloc(io_buf_cachep, GFP_KERNEL);

	if (!buf)

		return -ENOMEM;

		allocated = 1;

	}



	while (allocated)

		list_add_tail(&bufs[--allocated]->list, &ctx->io_buffers_cache);



	list_add_tail(&buf->list, &ctx->io_buffers_cache);

	return 0;

}