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[PATCH] lockdep: irqtrace subsystem, core

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Accurate hard-IRQ-flags and softirq-flags state tracing.

This allows us to attach extra functionality to IRQ flags on/off
events (such as trace-on/off).

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Ingo Molnar
2006-07-03 00:24:42 -07:00
committed by Linus Torvalds
parent 5bdc9b447c
commit de30a2b355
10 changed files with 313 additions and 30 deletions
Download Patch File Download Diff File Expand all files Collapse all files

19
kernel/fork.c
View File

@@ -968,6 +968,10 @@ static task_t *copy_process(unsigned long clone_flags,
if (!p)
goto fork_out;
#ifdef CONFIG_TRACE_IRQFLAGS
DEBUG_LOCKS_WARN_ON(!p->hardirqs_enabled);
DEBUG_LOCKS_WARN_ON(!p->softirqs_enabled);
#endif
retval = -EAGAIN;
if (atomic_read(&p->user->processes) >=
p->signal->rlim[RLIMIT_NPROC].rlim_cur) {
@@ -1042,6 +1046,21 @@ static task_t *copy_process(unsigned long clone_flags,
}
mpol_fix_fork_child_flag(p);
#endif
#ifdef CONFIG_TRACE_IRQFLAGS
p->irq_events = 0;
p->hardirqs_enabled = 0;
p->hardirq_enable_ip = 0;
p->hardirq_enable_event = 0;
p->hardirq_disable_ip = _THIS_IP_;
p->hardirq_disable_event = 0;
p->softirqs_enabled = 1;
p->softirq_enable_ip = _THIS_IP_;
p->softirq_enable_event = 0;
p->softirq_disable_ip = 0;
p->softirq_disable_event = 0;
p->hardirq_context = 0;
p->softirq_context = 0;
#endif
rt_mutex_init_task(p);

4
kernel/sched.c
View File

@@ -4462,7 +4462,9 @@ int __sched cond_resched_softirq(void)
BUG_ON(!in_softirq());
if (need_resched() && __resched_legal()) {
__local_bh_enable();
raw_local_irq_disable();
_local_bh_enable();
raw_local_irq_enable();
__cond_resched();
local_bh_disable();
return 1;

137
kernel/softirq.c
View File

@@ -61,6 +61,119 @@ static inline void wakeup_softirqd(void)
wake_up_process(tsk);
}
/*
* This one is for softirq.c-internal use,
* where hardirqs are disabled legitimately:
*/
static void __local_bh_disable(unsigned long ip)
{
unsigned long flags;
WARN_ON_ONCE(in_irq());
raw_local_irq_save(flags);
add_preempt_count(SOFTIRQ_OFFSET);
/*
* Were softirqs turned off above:
*/
if (softirq_count() == SOFTIRQ_OFFSET)
trace_softirqs_off(ip);
raw_local_irq_restore(flags);
}
void local_bh_disable(void)
{
__local_bh_disable((unsigned long)__builtin_return_address(0));
}
EXPORT_SYMBOL(local_bh_disable);
void __local_bh_enable(void)
{
WARN_ON_ONCE(in_irq());
/*
* softirqs should never be enabled by __local_bh_enable(),
* it always nests inside local_bh_enable() sections:
*/
WARN_ON_ONCE(softirq_count() == SOFTIRQ_OFFSET);
sub_preempt_count(SOFTIRQ_OFFSET);
}
EXPORT_SYMBOL_GPL(__local_bh_enable);
/*
* Special-case - softirqs can safely be enabled in
* cond_resched_softirq(), or by __do_softirq(),
* without processing still-pending softirqs:
*/
void _local_bh_enable(void)
{
WARN_ON_ONCE(in_irq());
WARN_ON_ONCE(!irqs_disabled());
if (softirq_count() == SOFTIRQ_OFFSET)
trace_softirqs_on((unsigned long)__builtin_return_address(0));
sub_preempt_count(SOFTIRQ_OFFSET);
}
EXPORT_SYMBOL(_local_bh_enable);
void local_bh_enable(void)
{
unsigned long flags;
WARN_ON_ONCE(in_irq());
WARN_ON_ONCE(irqs_disabled());
local_irq_save(flags);
/*
* 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();
local_irq_restore(flags);
preempt_check_resched();
}
EXPORT_SYMBOL(local_bh_enable);
void local_bh_enable_ip(unsigned long ip)
{
unsigned long flags;
WARN_ON_ONCE(in_irq());
local_irq_save(flags);
/*
* Are softirqs going to be turned on now:
*/
if (softirq_count() == SOFTIRQ_OFFSET)
trace_softirqs_on(ip);
/*
* 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();
local_irq_restore(flags);
preempt_check_resched();
}
EXPORT_SYMBOL(local_bh_enable_ip);
/*
* We restart softirq processing MAX_SOFTIRQ_RESTART times,
* and we fall back to softirqd after that.
@@ -80,8 +193,9 @@ asmlinkage void __do_softirq(void)
int cpu;
pending = local_softirq_pending();
__local_bh_disable((unsigned long)__builtin_return_address(0));
trace_softirq_enter();
local_bh_disable();
cpu = smp_processor_id();
restart:
/* Reset the pending bitmask before enabling irqs */
@@ -109,7 +223,8 @@ restart:
if (pending)
wakeup_softirqd();
__local_bh_enable();
trace_softirq_exit();
_local_bh_enable();
}
#ifndef __ARCH_HAS_DO_SOFTIRQ
@@ -136,23 +251,6 @@ EXPORT_SYMBOL(do_softirq);
#endif
void local_bh_enable(void)
{
WARN_ON(irqs_disabled());
/*
* 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();
preempt_check_resched();
}
EXPORT_SYMBOL(local_bh_enable);
#ifdef __ARCH_IRQ_EXIT_IRQS_DISABLED
# define invoke_softirq() __do_softirq()
#else
@@ -165,6 +263,7 @@ EXPORT_SYMBOL(local_bh_enable);
void irq_exit(void)
{
account_system_vtime(current);
trace_hardirq_exit();
sub_preempt_count(IRQ_EXIT_OFFSET);
if (!in_interrupt() && local_softirq_pending())
invoke_softirq();