提交 ac90f249 编写于 作者: J Jens Axboe

io_uring: expose single mmap capability

After commit 75b28aff we can get by with just a single mmap to
map both the sq and cq ring. However, userspace doesn't know that.

Add a features variable to io_uring_params, and notify userspace
that the kernel has this ability. This can then be used in liburing
(or in applications directly) to avoid the second mmap.
Signed-off-by: NJens Axboe <axboe@kernel.dk>
上级 75b28aff
......@@ -3391,6 +3391,8 @@ static int io_uring_create(unsigned entries, struct io_uring_params *p)
p->cq_off.ring_entries = offsetof(struct io_rings, cq_ring_entries);
p->cq_off.overflow = offsetof(struct io_rings, cq_overflow);
p->cq_off.cqes = offsetof(struct io_rings, cqes);
p->features = IORING_FEAT_SINGLE_MMAP;
return ret;
err:
io_ring_ctx_wait_and_kill(ctx);
......
......@@ -128,11 +128,17 @@ struct io_uring_params {
__u32 flags;
__u32 sq_thread_cpu;
__u32 sq_thread_idle;
__u32 resv[5];
__u32 features;
__u32 resv[4];
struct io_sqring_offsets sq_off;
struct io_cqring_offsets cq_off;
};
/*
* io_uring_params->features flags
*/
#define IORING_FEAT_SINGLE_MMAP (1U << 0)
/*
* io_uring_register(2) opcodes and arguments
*/
......
Markdown is supported
0% .
You are about to add 0 people to the discussion. Proceed with caution.
先完成此消息的编辑!
想要评论请 注册