Messages in this thread Patch in this message | | | Date | Thu, 27 Apr 2006 10:11:56 +0200 | From | Heiko Carstens <> | Subject | [patch] RCU: add comments to rcu_pending/rcu_needs_cpu |
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From: Heiko Carstens <heiko.carstens@de.ibm.com>
Add some comments to rcu_pending() and rcu_needs_cpu().
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> ---
Wording might be poor, but probably better than no comments at all.
kernel/rcupdate.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+)
diff -purN a/kernel/rcupdate.c b/kernel/rcupdate.c --- a/kernel/rcupdate.c 2006-04-27 09:30:23.000000000 +0200 +++ b/kernel/rcupdate.c 2006-04-27 09:56:51.000000000 +0200 @@ -479,12 +479,30 @@ static int __rcu_pending(struct rcu_ctrl return 0; } +/** + * rcu_pending - Check for pending RCU work on cpu. + * @cpu: cpu to check. + * + * Does RCU have some work pending on the specified cpu, so that there is a + * need to invoke rcu_check_callbacks() on the cpu? + */ int rcu_pending(int cpu) { return __rcu_pending(&rcu_ctrlblk, &per_cpu(rcu_data, cpu)) || __rcu_pending(&rcu_bh_ctrlblk, &per_cpu(rcu_bh_data, cpu)); } +/** + * rcu_needs_cpu - Determine if cpu will still be needed by RCU. + * @cpu: cpu to check. + * + * Determine whether the specified cpu will still be needed by RCU, or whether + * it can be turned off (e.g. by entering a tickless idle state). + * Note the difference to rcu_pending() which checks if there is some work to + * do that can be done immediately. While this function in addition checks if + * there would be some work to do if e.g. a different cpu finished working on + * the current batch. + */ int rcu_needs_cpu(int cpu) { struct rcu_data *rdp = &per_cpu(rcu_data, cpu); - 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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