Because the rcu_cblist_empty() just samples the ->head pointer, and because the rcu_cblist structure is quite straightforward, it makes sense to open-code rcu_cblist_empty(p) as !p->head, cutting out a level of indirection. This commit makes this change.
Reported-by: Ingo Molnar <[email protected]> Signed-off-by: Paul E. McKenney <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Linus Torvalds <[email protected]> --- kernel/rcu/rcu_segcblist.h | 8 +------- kernel/rcu/tree.c | 9 ++++----- kernel/rcu/tree_plugin.h | 4 ++-- 3 files changed, 7 insertions(+), 14 deletions(-) diff --git a/kernel/rcu/rcu_segcblist.h b/kernel/rcu/rcu_segcblist.h index 86bc1101b806..7d18d41f0116 100644 --- a/kernel/rcu/rcu_segcblist.h +++ b/kernel/rcu/rcu_segcblist.h @@ -22,12 +22,6 @@ #include <linux/rcu_segcblist.h> -/* Is simple callback list empty? */ -static inline bool rcu_cblist_empty(struct rcu_cblist *rclp) -{ - return !rclp->head; -} - /* Return number of callbacks in simple callback list. */ static inline long rcu_cblist_n_cbs(struct rcu_cblist *rclp) { @@ -66,7 +60,7 @@ static inline struct rcu_head *rcu_cblist_head(struct rcu_cblist *rclp) */ static inline struct rcu_head **rcu_cblist_tail(struct rcu_cblist *rclp) { - WARN_ON_ONCE(rcu_cblist_empty(rclp)); + WARN_ON_ONCE(!rclp->head); return rclp->tail; } diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 91fff49d5869..35152414760d 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -2647,9 +2647,9 @@ static void rcu_adopt_orphan_cbs(struct rcu_state *rsp, unsigned long flags) /* First adopt the ready-to-invoke callbacks, then the done ones. */ rcu_segcblist_insert_done_cbs(&rdp->cblist, &rsp->orphan_done); - WARN_ON_ONCE(!rcu_cblist_empty(&rsp->orphan_done)); + WARN_ON_ONCE(rsp->orphan_done.head); rcu_segcblist_insert_pend_cbs(&rdp->cblist, &rsp->orphan_pend); - WARN_ON_ONCE(!rcu_cblist_empty(&rsp->orphan_pend)); + WARN_ON_ONCE(rsp->orphan_pend.head); WARN_ON_ONCE(rcu_segcblist_empty(&rdp->cblist) != !rcu_segcblist_n_cbs(&rdp->cblist)); } @@ -2800,9 +2800,8 @@ static void rcu_do_batch(struct rcu_state *rsp, struct rcu_data *rdp) local_irq_save(flags); count = -rcu_cblist_n_cbs(&rcl); - trace_rcu_batch_end(rsp->name, count, !rcu_cblist_empty(&rcl), - need_resched(), is_idle_task(current), - rcu_is_callbacks_kthread()); + trace_rcu_batch_end(rsp->name, count, !!rcl.head, need_resched(), + is_idle_task(current), rcu_is_callbacks_kthread()); /* Update counts and requeue any remaining callbacks. */ rcu_segcblist_insert_done_cbs(&rdp->cblist, &rcl); diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index 7f1d677a2a25..6b4b1f8a272d 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -1942,12 +1942,12 @@ static bool __maybe_unused rcu_nocb_adopt_orphan_cbs(struct rcu_state *rsp, return false; /* First, enqueue the donelist, if any. This preserves CB ordering. */ - if (!rcu_cblist_empty(&rsp->orphan_done)) { + if (rsp->orphan_done.head) { __call_rcu_nocb_enqueue(rdp, rcu_cblist_head(&rsp->orphan_done), rcu_cblist_tail(&rsp->orphan_done), ql, qll, flags); } - if (!rcu_cblist_empty(&rsp->orphan_pend)) { + if (rsp->orphan_pend.head) { __call_rcu_nocb_enqueue(rdp, rcu_cblist_head(&rsp->orphan_pend), rcu_cblist_tail(&rsp->orphan_pend), ql, qll, flags); -- 2.5.2
