Commit b16da6ca authored by John Levon's avatar John Levon Committed by Jim Harris
Browse files

nvmf/vfio-user: avoid division in sq_head_advance() 



Avoid using the modulus operator in the hot-path sq_head_advance(),
by aping how cq_tail_advance() is written.

Suggested-by: default avatarJim Harris <james.r.harris@intel.com>
Signed-off-by: default avatarJohn Levon <john.levon@nutanix.com>
Change-Id: Id1e9d63a08e470344fdeb549d78ea505088b1a62
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/11436


Tested-by: default avatarSPDK CI Jenkins <sys_sgci@intel.com>
Community-CI: Broadcom CI <spdk-ci.pdl@broadcom.com>
Community-CI: Mellanox Build Bot
Reviewed-by: default avatarJim Harris <james.r.harris@intel.com>
Reviewed-by: default avatarChangpeng Liu <changpeng.liu@intel.com>
parent 8fd0e680

lib/nvmf/vfio_user.c

+7 −1
Original line number Diff line number Diff line
@@ -446,7 +446,13 @@ static inline void 
sq_head_advance(struct nvmf_vfio_user_sq *sq)

{

	assert(sq != NULL);

	*sq_headp(sq) = (*sq_headp(sq) + 1) % sq->size;



	assert(*sq_headp(sq) < sq->size);

	(*sq_headp(sq))++;



	if (spdk_unlikely(*sq_headp(sq) == sq->size)) {

		*sq_headp(sq) = 0;

	}

}



static inline void