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b4e6039e8a
This commit adds debug checks near the end of rcu_do_batch() that emit warnings if an empty rcu_segcblist structure has non-zero segment counts, or, conversely, if a non-empty structure has all-zero segment counts. Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> [ paulmck: Fix queue/segment-length checks. ] Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
109 lines
3.9 KiB
C
109 lines
3.9 KiB
C
/* SPDX-License-Identifier: GPL-2.0+ */
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/*
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* RCU segmented callback lists, internal-to-rcu header file
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*
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* Copyright IBM Corporation, 2017
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*
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* Authors: Paul E. McKenney <paulmck@linux.ibm.com>
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*/
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#include <linux/rcu_segcblist.h>
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/* Return number of callbacks in the specified callback list. */
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static inline long rcu_cblist_n_cbs(struct rcu_cblist *rclp)
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{
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return READ_ONCE(rclp->len);
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}
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/* Return number of callbacks in segmented callback list by summing seglen. */
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long rcu_segcblist_n_segment_cbs(struct rcu_segcblist *rsclp);
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void rcu_cblist_init(struct rcu_cblist *rclp);
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void rcu_cblist_enqueue(struct rcu_cblist *rclp, struct rcu_head *rhp);
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void rcu_cblist_flush_enqueue(struct rcu_cblist *drclp,
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struct rcu_cblist *srclp,
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struct rcu_head *rhp);
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struct rcu_head *rcu_cblist_dequeue(struct rcu_cblist *rclp);
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/*
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* Is the specified rcu_segcblist structure empty?
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*
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* But careful! The fact that the ->head field is NULL does not
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* necessarily imply that there are no callbacks associated with
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* this structure. When callbacks are being invoked, they are
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* removed as a group. If callback invocation must be preempted,
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* the remaining callbacks will be added back to the list. Either
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* way, the counts are updated later.
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*
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* So it is often the case that rcu_segcblist_n_cbs() should be used
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* instead.
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*/
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static inline bool rcu_segcblist_empty(struct rcu_segcblist *rsclp)
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{
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return !READ_ONCE(rsclp->head);
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}
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/* Return number of callbacks in segmented callback list. */
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static inline long rcu_segcblist_n_cbs(struct rcu_segcblist *rsclp)
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{
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#ifdef CONFIG_RCU_NOCB_CPU
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return atomic_long_read(&rsclp->len);
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#else
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return READ_ONCE(rsclp->len);
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#endif
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}
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/*
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* Is the specified rcu_segcblist enabled, for example, not corresponding
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* to an offline CPU?
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*/
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static inline bool rcu_segcblist_is_enabled(struct rcu_segcblist *rsclp)
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{
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return rsclp->enabled;
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}
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/* Is the specified rcu_segcblist offloaded? */
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static inline bool rcu_segcblist_is_offloaded(struct rcu_segcblist *rsclp)
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{
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return IS_ENABLED(CONFIG_RCU_NOCB_CPU) && rsclp->offloaded;
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}
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/*
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* Are all segments following the specified segment of the specified
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* rcu_segcblist structure empty of callbacks? (The specified
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* segment might well contain callbacks.)
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*/
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static inline bool rcu_segcblist_restempty(struct rcu_segcblist *rsclp, int seg)
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{
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return !READ_ONCE(*READ_ONCE(rsclp->tails[seg]));
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}
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void rcu_segcblist_inc_len(struct rcu_segcblist *rsclp);
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void rcu_segcblist_add_len(struct rcu_segcblist *rsclp, long v);
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void rcu_segcblist_init(struct rcu_segcblist *rsclp);
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void rcu_segcblist_disable(struct rcu_segcblist *rsclp);
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void rcu_segcblist_offload(struct rcu_segcblist *rsclp);
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bool rcu_segcblist_ready_cbs(struct rcu_segcblist *rsclp);
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bool rcu_segcblist_pend_cbs(struct rcu_segcblist *rsclp);
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struct rcu_head *rcu_segcblist_first_cb(struct rcu_segcblist *rsclp);
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struct rcu_head *rcu_segcblist_first_pend_cb(struct rcu_segcblist *rsclp);
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bool rcu_segcblist_nextgp(struct rcu_segcblist *rsclp, unsigned long *lp);
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void rcu_segcblist_enqueue(struct rcu_segcblist *rsclp,
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struct rcu_head *rhp);
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bool rcu_segcblist_entrain(struct rcu_segcblist *rsclp,
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struct rcu_head *rhp);
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void rcu_segcblist_extract_done_cbs(struct rcu_segcblist *rsclp,
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struct rcu_cblist *rclp);
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void rcu_segcblist_extract_pend_cbs(struct rcu_segcblist *rsclp,
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struct rcu_cblist *rclp);
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void rcu_segcblist_insert_count(struct rcu_segcblist *rsclp,
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struct rcu_cblist *rclp);
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void rcu_segcblist_insert_done_cbs(struct rcu_segcblist *rsclp,
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struct rcu_cblist *rclp);
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void rcu_segcblist_insert_pend_cbs(struct rcu_segcblist *rsclp,
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struct rcu_cblist *rclp);
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void rcu_segcblist_advance(struct rcu_segcblist *rsclp, unsigned long seq);
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bool rcu_segcblist_accelerate(struct rcu_segcblist *rsclp, unsigned long seq);
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void rcu_segcblist_merge(struct rcu_segcblist *dst_rsclp,
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struct rcu_segcblist *src_rsclp);
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