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From 3c9cbcdc1be978c0504991831def0bcec7634146 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Tue, 28 Jun 2011 15:46:49 +0200
Subject: [PATCH 049/270] softirq-split-out-code.patch
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
kernel/softirq.c | 94 ++++++++++++++++++++++++++++++------------------------
1 file changed, 52 insertions(+), 42 deletions(-)
diff --git a/kernel/softirq.c b/kernel/softirq.c
index 671f959..6ec3a78 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -76,6 +76,34 @@ static void wakeup_softirqd(void)
wake_up_process(tsk);
}
+static void handle_pending_softirqs(u32 pending, int cpu)
+{
+ struct softirq_action *h = softirq_vec;
+ unsigned int prev_count = preempt_count();
+
+ local_irq_enable();
+ for ( ; pending; h++, pending >>= 1) {
+ unsigned int vec_nr = h - softirq_vec;
+
+ if (!(pending & 1))
+ continue;
+
+ kstat_incr_softirqs_this_cpu(vec_nr);
+ trace_softirq_entry(vec_nr);
+ h->action(h);
+ trace_softirq_exit(vec_nr);
+ if (unlikely(prev_count != preempt_count())) {
+ printk(KERN_ERR
+ "huh, entered softirq %u %s %p with preempt_count %08x exited with %08x?\n",
+ vec_nr, softirq_to_name[vec_nr], h->action,
+ prev_count, (unsigned int) preempt_count());
+ preempt_count() = prev_count;
+ }
+ rcu_bh_qs(cpu);
+ }
+ local_irq_disable();
+}
+
/*
* preempt_count and SOFTIRQ_OFFSET usage:
* - preempt_count is changed by SOFTIRQ_OFFSET on entering or leaving
@@ -206,7 +234,6 @@ EXPORT_SYMBOL(local_bh_enable_ip);
asmlinkage void __do_softirq(void)
{
- struct softirq_action *h;
__u32 pending;
int max_restart = MAX_SOFTIRQ_RESTART;
int cpu;
@@ -215,7 +242,7 @@ asmlinkage void __do_softirq(void)
account_system_vtime(current);
__local_bh_disable((unsigned long)__builtin_return_address(0),
- SOFTIRQ_OFFSET);
+ SOFTIRQ_OFFSET);
lockdep_softirq_enter();
cpu = smp_processor_id();
@@ -223,36 +250,7 @@ restart:
/* Reset the pending bitmask before enabling irqs */
set_softirq_pending(0);
- local_irq_enable();
-
- h = softirq_vec;
-
- do {
- if (pending & 1) {
- unsigned int vec_nr = h - softirq_vec;
- int prev_count = preempt_count();
-
- kstat_incr_softirqs_this_cpu(vec_nr);
-
- trace_softirq_entry(vec_nr);
- h->action(h);
- trace_softirq_exit(vec_nr);
- if (unlikely(prev_count != preempt_count())) {
- printk(KERN_ERR "huh, entered softirq %u %s %p"
- "with preempt_count %08x,"
- " exited with %08x?\n", vec_nr,
- softirq_to_name[vec_nr], h->action,
- prev_count, preempt_count());
- preempt_count() = prev_count;
- }
-
- rcu_bh_qs(cpu);
- }
- h++;
- pending >>= 1;
- } while (pending);
-
- local_irq_disable();
+ handle_pending_softirqs(pending, cpu);
pending = local_softirq_pending();
if (pending && --max_restart)
@@ -267,6 +265,26 @@ restart:
__local_bh_enable(SOFTIRQ_OFFSET);
}
+/*
+ * Called with preemption disabled from run_ksoftirqd()
+ */
+static int ksoftirqd_do_softirq(int cpu)
+{
+ /*
+ * Preempt disable stops cpu going offline.
+ * If already offline, we'll be on wrong CPU:
+ * don't process.
+ */
+ if (cpu_is_offline(cpu))
+ return -1;
+
+ local_irq_disable();
+ if (local_softirq_pending())
+ __do_softirq();
+ local_irq_enable();
+ return 0;
+}
+
#ifndef __ARCH_HAS_DO_SOFTIRQ
asmlinkage void do_softirq(void)
@@ -739,22 +757,14 @@ static int run_ksoftirqd(void * __bind_cpu)
while (!kthread_should_stop()) {
preempt_disable();
- if (!local_softirq_pending()) {
+ if (!local_softirq_pending())
schedule_preempt_disabled();
- }
__set_current_state(TASK_RUNNING);
while (local_softirq_pending()) {
- /* Preempt disable stops cpu going offline.
- If already offline, we'll be on wrong CPU:
- don't process */
- if (cpu_is_offline((long)__bind_cpu))
+ if (ksoftirqd_do_softirq((long) __bind_cpu))
goto wait_to_die;
- local_irq_disable();
- if (local_softirq_pending())
- __do_softirq();
- local_irq_enable();
sched_preempt_enable_no_resched();
cond_resched();
preempt_disable();
--
1.7.10.4
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