From 962cf36c5bf6d2840b8d66ee9a606fae2f540bbd Mon Sep 17 00:00:00 2001
From: "Carlos R. Mafra" <crmafra2@gmail.com>
Date: Thu, 15 May 2008 11:15:37 -0300
Subject: [PATCH 1/3] Remove argument from open_softirq which is always NULL
As git-grep shows, open_softirq() is always called with the last argument
being NULL
block/blk-core.c: open_softirq(BLOCK_SOFTIRQ, blk_done_softirq, NULL);
kernel/hrtimer.c: open_softirq(HRTIMER_SOFTIRQ, run_hrtimer_softirq, NULL);
kernel/rcuclassic.c: open_softirq(RCU_SOFTIRQ, rcu_process_callbacks, NULL);
kernel/rcupreempt.c: open_softirq(RCU_SOFTIRQ, rcu_process_callbacks, NULL);
kernel/sched.c: open_softirq(SCHED_SOFTIRQ, run_rebalance_domains, NULL);
kernel/softirq.c: open_softirq(TASKLET_SOFTIRQ, tasklet_action, NULL);
kernel/softirq.c: open_softirq(HI_SOFTIRQ, tasklet_hi_action, NULL);
kernel/timer.c: open_softirq(TIMER_SOFTIRQ, run_timer_softirq, NULL);
net/core/dev.c: open_softirq(NET_TX_SOFTIRQ, net_tx_action, NULL);
net/core/dev.c: open_softirq(NET_RX_SOFTIRQ, net_rx_action, NULL);
This observation has already been made by Matthew Wilcox in June 2002
(http://www.cs.helsinki.fi/linux/linux-kernel/2002-25/0687.html)
"I notice that none of the current softirq routines use the data element
passed to them."
and the situation hasn't changed since them. So it appears we can safely
remove that extra argument to save 128 (54) bytes of kernel data (text).
Signed-off-by: Carlos R. Mafra <crmafra@ift.unesp.br>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
block/blk-core.c | 2 +-
include/linux/interrupt.h | 3 +--
kernel/hrtimer.c | 2 +-
kernel/rcuclassic.c | 2 +-
kernel/rcupreempt.c | 2 +-
kernel/sched.c | 2 +-
kernel/softirq.c | 7 +++----
kernel/timer.c | 2 +-
net/core/dev.c | 4 ++--
9 files changed, 12 insertions(+), 14 deletions(-)
diff --git a/block/blk-core.c b/block/blk-core.c
index 6a9cc0d22a61..75fdc65136e8 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -2048,7 +2048,7 @@ int __init blk_dev_init(void)
for_each_possible_cpu(i)
INIT_LIST_HEAD(&per_cpu(blk_cpu_done, i));
- open_softirq(BLOCK_SOFTIRQ, blk_done_softirq, NULL);
+ open_softirq(BLOCK_SOFTIRQ, blk_done_softirq);
register_hotcpu_notifier(&blk_cpu_notifier);
return 0;
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index f1fc7470d26c..a86186dd0474 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -285,12 +285,11 @@ enum
struct softirq_action
{
void (*action)(struct softirq_action *);
- void *data;
};
asmlinkage void do_softirq(void);
asmlinkage void __do_softirq(void);
-extern void open_softirq(int nr, void (*action)(struct softirq_action*), void *data);
+extern void open_softirq(int nr, void (*action)(struct softirq_action *));
extern void softirq_init(void);
#define __raise_softirq_irqoff(nr) do { or_softirq_pending(1UL << (nr)); } while (0)
extern void raise_softirq_irqoff(unsigned int nr);
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index 421be5fe5cc7..861b4088092a 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -1669,7 +1669,7 @@ void __init hrtimers_init(void)
(void *)(long)smp_processor_id());
register_cpu_notifier(&hrtimers_nb);
#ifdef CONFIG_HIGH_RES_TIMERS
- open_softirq(HRTIMER_SOFTIRQ, run_hrtimer_softirq, NULL);
+ open_softirq(HRTIMER_SOFTIRQ, run_hrtimer_softirq);
#endif
}
diff --git a/kernel/rcuclassic.c b/kernel/rcuclassic.c
index f4ffbd0f306f..f6e01f3ae9c6 100644
--- a/kernel/rcuclassic.c
+++ b/kernel/rcuclassic.c
@@ -529,7 +529,7 @@ static void __cpuinit rcu_online_cpu(int cpu)
rcu_init_percpu_data(cpu, &rcu_ctrlblk, rdp);
rcu_init_percpu_data(cpu, &rcu_bh_ctrlblk, bh_rdp);
- open_softirq(RCU_SOFTIRQ, rcu_process_callbacks, NULL);
+ open_softirq(RCU_SOFTIRQ, rcu_process_callbacks);
}
static int __cpuinit rcu_cpu_notify(struct notifier_block *self,
diff --git a/kernel/rcupreempt.c b/kernel/rcupreempt.c
index e1cdf196a515..9dd827db359f 100644
--- a/kernel/rcupreempt.c
+++ b/kernel/rcupreempt.c
@@ -1125,7 +1125,7 @@ void __init __rcu_init(void)
for_each_online_cpu(cpu)
rcu_cpu_notify(&rcu_nb, CPU_UP_PREPARE, (void *)(long) cpu);
- open_softirq(RCU_SOFTIRQ, rcu_process_callbacks, NULL);
+ open_softirq(RCU_SOFTIRQ, rcu_process_callbacks);
}
/*
diff --git a/kernel/sched.c b/kernel/sched.c
index cfa222a91539..56ea3a203a5a 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -8154,7 +8154,7 @@ void __init sched_init(void)
#endif
#ifdef CONFIG_SMP
- open_softirq(SCHED_SOFTIRQ, run_rebalance_domains, NULL);
+ open_softirq(SCHED_SOFTIRQ, run_rebalance_domains);
#endif
#ifdef CONFIG_RT_MUTEXES
diff --git a/kernel/softirq.c b/kernel/softirq.c
index 36e061740047..059256874e9b 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -347,9 +347,8 @@ void raise_softirq(unsigned int nr)
local_irq_restore(flags);
}
-void open_softirq(int nr, void (*action)(struct softirq_action*), void *data)
+void open_softirq(int nr, void (*action)(struct softirq_action *))
{
- softirq_vec[nr].data = data;
softirq_vec[nr].action = action;
}
@@ -503,8 +502,8 @@ void __init softirq_init(void)
&per_cpu(tasklet_hi_vec, cpu).head;
}
- open_softirq(TASKLET_SOFTIRQ, tasklet_action, NULL);
- open_softirq(HI_SOFTIRQ, tasklet_hi_action, NULL);
+ open_softirq(TASKLET_SOFTIRQ, tasklet_action);
+ open_softirq(HI_SOFTIRQ, tasklet_hi_action);
}
static int ksoftirqd(void * __bind_cpu)
diff --git a/kernel/timer.c b/kernel/timer.c
index ceacc6626572..b4da888497fa 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -1502,7 +1502,7 @@ void __init init_timers(void)
BUG_ON(err == NOTIFY_BAD);
register_cpu_notifier(&timers_nb);
- open_softirq(TIMER_SOFTIRQ, run_timer_softirq, NULL);
+ open_softirq(TIMER_SOFTIRQ, run_timer_softirq);
}
/**
diff --git a/net/core/dev.c b/net/core/dev.c
index 582963077877..cf0e16731dc7 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4563,8 +4563,8 @@ static int __init net_dev_init(void)
dev_boot_phase = 0;
- open_softirq(NET_TX_SOFTIRQ, net_tx_action, NULL);
- open_softirq(NET_RX_SOFTIRQ, net_rx_action, NULL);
+ open_softirq(NET_TX_SOFTIRQ, net_tx_action);
+ open_softirq(NET_RX_SOFTIRQ, net_rx_action);
hotcpu_notifier(dev_cpu_callback, 0);
dst_init();
From 4620b49f76096fa5183eecad7d689faa898a4c82 Mon Sep 17 00:00:00 2001
From: Vegard Nossum <vegard.nossum@gmail.com>
Date: Thu, 12 Jun 2008 23:21:53 +0200
Subject: [PATCH 2/3] softirq: remove initialization of static per-cpu variable
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
kernel/softirq.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/kernel/softirq.c b/kernel/softirq.c
index 059256874e9b..86775340ef1d 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -359,10 +359,8 @@ struct tasklet_head
struct tasklet_struct **tail;
};
-/* Some compilers disobey section attribute on statics when not
- initialized -- RR */
-static DEFINE_PER_CPU(struct tasklet_head, tasklet_vec) = { NULL };
-static DEFINE_PER_CPU(struct tasklet_head, tasklet_hi_vec) = { NULL };
+static DEFINE_PER_CPU(struct tasklet_head, tasklet_vec);
+static DEFINE_PER_CPU(struct tasklet_head, tasklet_hi_vec);
void __tasklet_schedule(struct tasklet_struct *t)
{
From 0f476b6d91a1395bda6464e653ce66ea9bea7167 Mon Sep 17 00:00:00 2001
From: Johannes Berg <johannes@sipsolutions.net>
Date: Wed, 18 Jun 2008 09:29:37 +0200
Subject: [PATCH 3/3] softirq: remove irqs_disabled warning from
local_bh_enable
There's no need to use local_irq_save() over local_irq_disable() in the
local_bh_enable code since it is a bug to call it with irqs disabled and
do_softirq will enable irqs if there is any pending work.
Consolidate the code from local_bh_enable and ..._ip to avoid having a
disconnect between them in the warnings they trigger that is currently
there.
Also always trigger the warning on in_irq(), not just in the
trace-irqflags case.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Cc: Michael Buesch <mb@bu3sch.de>
Cc: David Ellingsworth <david@identd.dyndns.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
kernel/softirq.c | 56 +++++++++++++-----------------------------------
1 file changed, 15 insertions(+), 41 deletions(-)
diff --git a/kernel/softirq.c b/kernel/softirq.c
index 86775340ef1d..2cf2502b7c73 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -131,48 +131,11 @@ void _local_bh_enable(void)
EXPORT_SYMBOL(_local_bh_enable);
-void local_bh_enable(void)
+static inline void _local_bh_enable_ip(unsigned long ip)
{
+ WARN_ON_ONCE(in_irq() || irqs_disabled());
#ifdef CONFIG_TRACE_IRQFLAGS
- unsigned long flags;
-
- WARN_ON_ONCE(in_irq());
-#endif
- WARN_ON_ONCE(irqs_disabled());
-
-#ifdef CONFIG_TRACE_IRQFLAGS
- local_irq_save(flags);
-#endif
- /*
- * Are softirqs going to be turned on now:
- */
- if (softirq_count() == SOFTIRQ_OFFSET)
- trace_softirqs_on((unsigned long)__builtin_return_address(0));
- /*
- * Keep preemption disabled until we are done with
- * softirq processing:
- */
- sub_preempt_count(SOFTIRQ_OFFSET - 1);
-
- if (unlikely(!in_interrupt() && local_softirq_pending()))
- do_softirq();
-
- dec_preempt_count();
-#ifdef CONFIG_TRACE_IRQFLAGS
- local_irq_restore(flags);
-#endif
- preempt_check_resched();
-}
-EXPORT_SYMBOL(local_bh_enable);
-
-void local_bh_enable_ip(unsigned long ip)
-{
-#ifdef CONFIG_TRACE_IRQFLAGS
- unsigned long flags;
-
- WARN_ON_ONCE(in_irq());
-
- local_irq_save(flags);
+ local_irq_disable();
#endif
/*
* Are softirqs going to be turned on now:
@@ -190,10 +153,21 @@ void local_bh_enable_ip(unsigned long ip)
dec_preempt_count();
#ifdef CONFIG_TRACE_IRQFLAGS
- local_irq_restore(flags);
+ local_irq_enable();
#endif
preempt_check_resched();
}
+
+void local_bh_enable(void)
+{
+ _local_bh_enable_ip((unsigned long)__builtin_return_address(0));
+}
+EXPORT_SYMBOL(local_bh_enable);
+
+void local_bh_enable_ip(unsigned long ip)
+{
+ _local_bh_enable_ip(ip);
+}
EXPORT_SYMBOL(local_bh_enable_ip);
/*