diff options
| author | Paul E. McKenney <paulmck@linux.ibm.com> | 2019-07-02 03:36:53 +0300 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.ibm.com> | 2019-08-14 00:35:49 +0300 |
| commit | eda669a6a2c517fd6db41d0fe3c95c1b749c60bd (patch) | |
| tree | 00d46158f1c02fff813a6d874f2ab0bef81078af /kernel/rcu/rcu_segcblist.h | |
| parent | faca5c250935262f026cac1bb951a0f7672474b8 (diff) | |
| download | linux-eda669a6a2c517fd6db41d0fe3c95c1b749c60bd.tar.xz | |
rcu/nocb: Atomic ->len field in rcu_segcblist structure
Upcoming ->nocb_lock contention-reduction work requires that the
rcu_segcblist structure's ->len field be concurrently manipulated,
but only if there are no-CBs CPUs in the kernel. This commit
therefore makes this ->len field be an atomic_long_t, but only
in CONFIG_RCU_NOCB_CPU=y kernels.
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
Diffstat (limited to 'kernel/rcu/rcu_segcblist.h')
| -rw-r--r-- | kernel/rcu/rcu_segcblist.h | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/kernel/rcu/rcu_segcblist.h b/kernel/rcu/rcu_segcblist.h index db38f0a512c4..1ff996647d3c 100644 --- a/kernel/rcu/rcu_segcblist.h +++ b/kernel/rcu/rcu_segcblist.h @@ -9,6 +9,12 @@ #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); +} + /* * Account for the fact that a previously dequeued callback turned out * to be marked as lazy. @@ -42,7 +48,11 @@ static inline bool rcu_segcblist_empty(struct rcu_segcblist *rsclp) /* 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 } /* Return number of lazy callbacks in segmented callback list. */ @@ -54,7 +64,7 @@ static inline long rcu_segcblist_n_lazy_cbs(struct rcu_segcblist *rsclp) /* Return number of lazy callbacks in segmented callback list. */ static inline long rcu_segcblist_n_nonlazy_cbs(struct rcu_segcblist *rsclp) { - return rsclp->len - rsclp->len_lazy; + return rcu_segcblist_n_cbs(rsclp) - rsclp->len_lazy; } /* |