Messages in this thread Patch in this message | | | Date | Tue, 25 Apr 2006 14:27:06 +0200 | From | Heiko Carstens <> | Subject | [patch] RCU: introduce rcu_needs_cpu() interface |
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From: Heiko Carstens <heiko.carstens@de.ibm.com> From: "Paul E. McKenney" <paulmck@us.ibm.com>
Introduce rcu_needs_cpu() interface. This can be used to tell if there will be a new rcu batch on a cpu soon by looking at the curlist pointer. This can be used to avoid to enter a tickless idle state where the cpu would miss that a new batch is ready when rcu_start_batch would be called on a different cpu.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> ---
This one replaces rcu-introduce-rcu_soon_pending-interface.patch .
include/linux/rcupdate.h | 1 + kernel/rcupdate.c | 8 ++++++++ 2 files changed, 9 insertions(+)
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 5673008..970284f 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -132,6 +132,7 @@ static inline void rcu_bh_qsctr_inc(int } extern int rcu_pending(int cpu); +extern int rcu_needs_cpu(int cpu); /** * rcu_read_lock - mark the beginning of an RCU read-side critical section. diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c index 13458bb..651ac14 100644 --- a/kernel/rcupdate.c +++ b/kernel/rcupdate.c @@ -485,6 +485,14 @@ int rcu_pending(int cpu) __rcu_pending(&rcu_bh_ctrlblk, &per_cpu(rcu_bh_data, cpu)); } +int rcu_needs_cpu(int cpu) +{ + struct rcu_data *rdp = &per_cpu(rcu_data, cpu); + struct rcu_data *rdp_bh = &per_cpu(rcu_bh_data, cpu); + + return (!!rdp->curlist || !!rdp_bh->curlist || rcu_pending(cpu)); +} + void rcu_check_callbacks(int cpu, int user) { if (user || - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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