On Mon, Aug 12, 2019 at 6:03 PM Jens Axboe <axboe@xxxxxxxxx> wrote:
>
> On 8/12/19 7:55 AM, Bart Van Assche wrote:
> > On 8/12/19 5:39 AM, Julia Suvorova wrote:
> >> -#define mb() asm volatile("mfence" ::: "memory")
> >> -#define rmb() asm volatile("lfence" ::: "memory")
> >> -#define wmb() asm volatile("sfence" ::: "memory")
> >> -#define smp_rmb() barrier()
> >> -#define smp_wmb() barrier()
> >> +#define io_uring_mb() asm volatile("mfence" ::: "memory")
> >> +#define io_uring_rmb() asm volatile("lfence" ::: "memory")
> >> +#define io_uring_wmb() asm volatile("sfence" ::: "memory")
> >> +#define io_uring_smp_rmb() io_uring_barrier()
> >> +#define io_uring_smp_wmb() io_uring_barrier()
> >
> > Do users of liburing need these macros? If not, have you considered to
> > move these macros to a new header file that is only used inside liburing
> > and such that these macros are no longer visible to liburing users?
>
> The exposed API should not need any explicit barriers from the user,
> so this suggestion makes a lot of sense to me.
How about moving the definition of io_uring_cqe_seen() with whole
io_uring_cq_advance() and io_uring_for_each_cqe() from liburing.h to
queue.c? This way we can cover all barriers, and leave barrier.h local.
Do you need io_uring_cq_advance and io_uring_for_each_cqe in the
library?
Best regards, Julia Suvorova.
