Attachment 291064 Details for Bug 427998 – Git 986733e01d258c26107f1da9d8d47c718349ad2f backported to 2.6.9-67.EL

[patch] Git 986733e01d258c26107f1da9d8d47c718349ad2f backported to 2.6.9-67.EL

git-986733e01d258c26107f1da9d8d47c718349ad2f (text/plain), 2.29 KB, created by Ian Campbell on 2008-01-08 16:21:55 UTC

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Creator: Ian Campbell

Created: 2008-01-08 16:21:55 UTC

Size: 2.29 KB

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obsolete

>commit 986733e01d258c26107f1da9d8d47c718349ad2f
>Author: Heiko Carstens <heiko.carstens@de.ibm.com>
>Date:   Mon May 15 09:43:58 2006 -0700
>
>    [PATCH] RCU: introduce rcu_needs_cpu() interface
>    
>    With "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>
>    Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
>    Signed-off-by: Andrew Morton <akpm@osdl.org>
>    Signed-off-by: Linus Torvalds <torvalds@osdl.org>
>
>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 cpu)
> }
> 
> 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 6d32ff2..2058f88 100644
>--- a/kernel/rcupdate.c
>+++ b/kernel/rcupdate.c
>@@ -479,12 +479,31 @@ static int __rcu_pending(struct rcu_ctrlblk *rcp, struct rcu_data *rdp)
> 	return 0;
> }
> 
>+/*
>+ * Check to see if there is any immediate RCU-related work to be done
>+ * by the current CPU, returning 1 if so.  This function is part of the
>+ * RCU implementation; it is -not- an exported member of the RCU API.
>+ */
> 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));
> }
> 
>+/*
>+ * Check to see if any future RCU-related work will need to be done
>+ * by the current CPU, even if none need be done immediately, returning
>+ * 1 if so.  This function is part of the RCU implementation; it is -not-
>+ * an exported member of the RCU API.
>+ */
>+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 ||

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Attachments on bug 427998: 291063 | 291064 | 291065 | 291066