The patch titled
RCU: introduce rcu_needs_cpu() interface
has been removed from the -mm tree. Its filename is
rcu-introduce-rcu_needs_cpu-interface.patch
This patch was probably dropped from -mm because
it has now been merged into a subsystem tree or
into Linus's tree, or because it was folded into
its parent patch in the -mm tree.
From: Heiko Carstens <heiko.carstens@xxxxxxxxxx>,
"Paul E. McKenney" <paulmck@xxxxxxxxxx>
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@xxxxxxxxxx>
Cc: "Paul E. McKenney" <paulmck@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
include/linux/rcupdate.h | 1 +
kernel/rcupdate.c | 19 +++++++++++++++++++
2 files changed, 20 insertions(+)
diff -puN include/linux/rcupdate.h~rcu-introduce-rcu_needs_cpu-interface include/linux/rcupdate.h
--- devel/include/linux/rcupdate.h~rcu-introduce-rcu_needs_cpu-interface 2006-05-15 09:43:25.000000000 -0700
+++ devel-akpm/include/linux/rcupdate.h 2006-05-15 09:43:25.000000000 -0700
@@ -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 -puN kernel/rcupdate.c~rcu-introduce-rcu_needs_cpu-interface kernel/rcupdate.c
--- devel/kernel/rcupdate.c~rcu-introduce-rcu_needs_cpu-interface 2006-05-15 09:43:25.000000000 -0700
+++ devel-akpm/kernel/rcupdate.c 2006-05-15 09:43:25.000000000 -0700
@@ -479,12 +479,31 @@ static int __rcu_pending(struct rcu_ctrl
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 ||
_
Patches currently in -mm which might be from heiko.carstens@xxxxxxxxxx are
origin.patch
git-klibc.patch
adjust-handle_irr_event-return-type.patch
-
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