The patch titled
rcu: softirq for RCU
has been added to the -mm tree. Its filename is
rcu-softirq-for-rcu.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: rcu: softirq for RCU
From: Dipankar Sarma <dipankar@xxxxxxxxxx>
Finally, RCU gets its own softirq. With it being used extensively, the
per-cpu tasklet used earlier was just a softirq with overheads. This makes
things more efficient.
Signed-off-by: Dipankar Sarma <dipankar@xxxxxxxxxx>
Acked-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
include/linux/interrupt.h | 1 +
kernel/rcuclassic.c | 12 +++++-------
2 files changed, 6 insertions(+), 7 deletions(-)
diff -puN include/linux/interrupt.h~rcu-softirq-for-rcu include/linux/interrupt.h
--- a/include/linux/interrupt.h~rcu-softirq-for-rcu
+++ a/include/linux/interrupt.h
@@ -236,6 +236,7 @@ enum
#ifdef CONFIG_HIGH_RES_TIMERS
HRTIMER_SOFTIRQ,
#endif
+ RCU_SOFTIRQ,
};
/* softirq mask and active fields moved to irq_cpustat_t in
diff -puN kernel/rcuclassic.c~rcu-softirq-for-rcu kernel/rcuclassic.c
--- a/kernel/rcuclassic.c~rcu-softirq-for-rcu
+++ a/kernel/rcuclassic.c
@@ -69,7 +69,6 @@ DEFINE_PER_CPU(struct rcu_data, rcu_data
DEFINE_PER_CPU(struct rcu_data, rcu_bh_data) = { 0L };
/* Fake initialization required by compiler */
-static DEFINE_PER_CPU(struct tasklet_struct, rcu_tasklet) = {NULL};
static int blimit = 10;
static int qhimark = 10000;
static int qlowmark = 100;
@@ -215,7 +214,7 @@ static void rcu_do_batch(struct rcu_data
if (!rdp->donelist)
rdp->donetail = &rdp->donelist;
else
- tasklet_schedule(&per_cpu(rcu_tasklet, rdp->cpu));
+ raise_softirq(RCU_SOFTIRQ);
}
/*
@@ -367,7 +366,6 @@ static void rcu_offline_cpu(int cpu)
&per_cpu(rcu_bh_data, cpu));
put_cpu_var(rcu_data);
put_cpu_var(rcu_bh_data);
- tasklet_kill_immediate(&per_cpu(rcu_tasklet, cpu), cpu);
}
#else
@@ -379,7 +377,7 @@ static void rcu_offline_cpu(int cpu)
#endif
/*
- * This does the RCU processing work from tasklet context.
+ * This does the RCU processing work from softirq context.
*/
static void __rcu_process_callbacks(struct rcu_ctrlblk *rcp,
struct rcu_data *rdp)
@@ -424,7 +422,7 @@ static void __rcu_process_callbacks(stru
rcu_do_batch(rdp);
}
-static void rcu_process_callbacks(unsigned long unused)
+static void rcu_process_callbacks(struct softirq_action *unused)
{
__rcu_process_callbacks(&rcu_ctrlblk, &__get_cpu_var(rcu_data));
__rcu_process_callbacks(&rcu_bh_ctrlblk, &__get_cpu_var(rcu_bh_data));
@@ -488,7 +486,7 @@ void rcu_check_callbacks(int cpu, int us
rcu_bh_qsctr_inc(cpu);
} else if (!in_softirq())
rcu_bh_qsctr_inc(cpu);
- tasklet_schedule(&per_cpu(rcu_tasklet, cpu));
+ raise_softirq(RCU_SOFTIRQ);
}
static void rcu_init_percpu_data(int cpu, struct rcu_ctrlblk *rcp,
@@ -511,7 +509,7 @@ static void __devinit rcu_online_cpu(int
rcu_init_percpu_data(cpu, &rcu_ctrlblk, rdp);
rcu_init_percpu_data(cpu, &rcu_bh_ctrlblk, bh_rdp);
- tasklet_init(&per_cpu(rcu_tasklet, cpu), rcu_process_callbacks, 0UL);
+ open_softirq(RCU_SOFTIRQ, rcu_process_callbacks, NULL);
}
static int __cpuinit rcu_cpu_notify(struct notifier_block *self,
_
Patches currently in -mm which might be from dipankar@xxxxxxxxxx are
rcu-split-classic-rcu.patch
rcu-softirq-for-rcu.patch
rcu-fix-barriers.patch
rcu-preemptible-rcu.patch
rcu-debug-trace-for-rcu.patch
rcu-trivial-fixes.patch
-
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