Differential D47450 Diff 146068 sys/sys/refcount.h

Changeset View

Standalone View

sys/sys/refcount.h

	Show All 22 Lines
	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY			* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF			* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	* SUCH DAMAGE.			* SUCH DAMAGE.
	*/			*/

	#ifndef __SYS_REFCOUNT_H__			#ifndef __SYS_REFCOUNT_H__
	#define __SYS_REFCOUNT_H__			#define __SYS_REFCOUNT_H__

	#include <machine/atomic.h>			#include <sys/types.h>
				#include <sys/kassert.h>
	#include <sys/systm.h>
	#if !defined(_KERNEL) && !defined(_STANDALONE)			#if !defined(_KERNEL) && !defined(_STANDALONE)
	#include <stdbool.h>			#include <stdbool.h>
	#endif			#endif

				#include <machine/atomic.h>

	#define REFCOUNT_SATURATED(val) (((val) & (1U << 31)) != 0)			#define REFCOUNT_SATURATED(val) (((val) & (1U << 31)) != 0)
	#define REFCOUNT_SATURATION_VALUE (3U << 30)			#define REFCOUNT_SATURATION_VALUE (3U << 30)

	/*			/*
	* Attempt to handle reference count overflow and underflow. Force the counter			* Attempt to handle reference count overflow and underflow. Force the counter
	* to stay at the saturation value so that a counter overflow cannot trigger			* to stay at the saturation value so that a counter overflow cannot trigger
	* destruction of the containing object and instead leads to a less harmful			* destruction of the containing object and instead leads to a less harmful
	* memory leak.			* memory leak.
	*/			*/
	static __inline void			static __inline void
	_refcount_update_saturated(volatile u_int *count)			_refcount_update_saturated(volatile u_int *count)
				kibUnsubmitted Done Inline Actions u_int comes from machine/atomic.h->sys/atomic_common.h->sys/types.h. Do we want to rely on this, or should sys/types.h included there directly? kib: u_int comes from machine/atomic.h->sys/atomic_common.h->sys/types.h. Do we want to rely on this…
				markjAuthorUnsubmitted Done Inline Actions I'd rather replace u_int with unsigned int, but it's a lot of churn. markj: I'd rather replace u_int with unsigned int, but it's a lot of churn.
				impUnsubmitted Not Done Inline Actions That might be only marginally better. You'd avoid the namespace pollution of types.h, since u_int isn't defined in _types.h.. But it would be a lot more churn... So either choice is fine. imp: That might be only marginally better. You'd avoid the namespace pollution of types.h, since…
	{			{
	#ifdef INVARIANTS			#ifdef INVARIANTS
	panic("refcount %p wraparound", count);			panic("refcount %p wraparound", count);
	#else			#else
	atomic_store_int(count, REFCOUNT_SATURATION_VALUE);			atomic_store_int(count, REFCOUNT_SATURATION_VALUE);
	#endif			#endif
	}			}

	▲ Show 20 Lines • Show All 163 Lines • Show Last 20 Lines