kernel/rcu/rcu_segcblist.h

Source file repositories/reference/linux-study-clean/kernel/rcu/rcu_segcblist.h

File Facts

System
Linux kernel
Corpus path
kernel/rcu/rcu_segcblist.h
Extension
.h
Size
4878 bytes
Lines
146
Domain
Core OS
Bucket
Scheduler, Processes, Timers, Sync, And Syscalls
Inferred role
Core OS: implementation source
Status
source implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

Dependency Surface

Detected Declarations

Annotated Snippet

#include <linux/rcu_segcblist.h>

/* Return number of callbacks in the specified callback list. */
static inline long rcu_cblist_n_cbs(struct rcu_cblist *rclp)
{
	return READ_ONCE(rclp->len);
}

long rcu_segcblist_get_seglen(struct rcu_segcblist *rsclp, int seg);

/* Return number of callbacks in segmented callback list by summing seglen. */
long rcu_segcblist_n_segment_cbs(struct rcu_segcblist *rsclp);

void rcu_cblist_init(struct rcu_cblist *rclp);
void rcu_cblist_enqueue(struct rcu_cblist *rclp, struct rcu_head *rhp);
void rcu_cblist_flush_enqueue(struct rcu_cblist *drclp,
			      struct rcu_cblist *srclp,
			      struct rcu_head *rhp);
struct rcu_head *rcu_cblist_dequeue(struct rcu_cblist *rclp);

/*
 * Is the specified rcu_segcblist structure empty?
 *
 * But careful!  The fact that the ->head field is NULL does not
 * necessarily imply that there are no callbacks associated with
 * this structure.  When callbacks are being invoked, they are
 * removed as a group.  If callback invocation must be preempted,
 * the remaining callbacks will be added back to the list.  Either
 * way, the counts are updated later.
 *
 * So it is often the case that rcu_segcblist_n_cbs() should be used
 * instead.
 */
static inline bool rcu_segcblist_empty(struct rcu_segcblist *rsclp)
{
	return !READ_ONCE(rsclp->head);
}

/* Return number of callbacks in segmented callback list. */
static inline long rcu_segcblist_n_cbs(struct rcu_segcblist *rsclp)
{
#ifdef CONFIG_RCU_NOCB_CPU
	return atomic_long_read(&rsclp->len);
#else
	return READ_ONCE(rsclp->len);
#endif
}

static inline void rcu_segcblist_set_flags(struct rcu_segcblist *rsclp,
					   int flags)
{
	WRITE_ONCE(rsclp->flags, rsclp->flags | flags);
}

static inline void rcu_segcblist_clear_flags(struct rcu_segcblist *rsclp,
					     int flags)
{
	WRITE_ONCE(rsclp->flags, rsclp->flags & ~flags);
}

static inline bool rcu_segcblist_test_flags(struct rcu_segcblist *rsclp,
					    int flags)
{
	return READ_ONCE(rsclp->flags) & flags;
}

/*
 * Is the specified rcu_segcblist enabled, for example, not corresponding
 * to an offline CPU?
 */
static inline bool rcu_segcblist_is_enabled(struct rcu_segcblist *rsclp)
{
	return rcu_segcblist_test_flags(rsclp, SEGCBLIST_ENABLED);
}

/*
 * Is the specified rcu_segcblist NOCB offloaded (or in the middle of the
 * [de]offloading process)?
 */
static inline bool rcu_segcblist_is_offloaded(struct rcu_segcblist *rsclp)
{
	if (IS_ENABLED(CONFIG_RCU_NOCB_CPU) &&
	    rcu_segcblist_test_flags(rsclp, SEGCBLIST_OFFLOADED))
		return true;

	return false;
}

/*
 * Are all segments following the specified segment of the specified

Annotation

Implementation Notes