Ingo Molnar wrote:
>
> On Wed, 24 Jul 2002, Christoph Hellwig wrote:
>
> > > - move the irqs-off check into preempt_schedule() and remove
> > > CONFIG_DEBUG_IRQ_SCHEDULE.
> >
> > the config.in entry is still present..
>
> indeed. Fix is in -H5:
We need to verify correct usage of the
irq_enable/irq_restore() least we miss a preemption. The
attached patch allows one to enable a test on the these
macros to verify that they are being correctly used.
Ingo, I am not sure about the change in fork.c. Don't we
always want to check for preemption at the end of this
irq_disable?
Patch is against Ingo's H6.
-- George Anzinger george@mvista.com High-res-timers: http://sourceforge.net/projects/high-res-timers/ Real time sched: http://sourceforge.net/projects/rtsched/ Preemption patch: http://www.kernel.org/pub/linux/kernel/people/rml
diff -urP -I \$Id:.*Exp \$ -X /usr/src/patch.exclude linux-2.5.27-ingo-H6-org/arch/i386/config.in linux/arch/i386/config.in --- linux-2.5.27-ingo-H6-org/arch/i386/config.in Mon Jul 22 14:19:20 2002 +++ linux/arch/i386/config.in Wed Jul 24 12:13:56 2002 @@ -412,6 +412,7 @@ bool 'Kernel debugging' CONFIG_DEBUG_KERNEL if [ "$CONFIG_DEBUG_KERNEL" != "n" ]; then + bool ' Debug IRQ preempt interaction' CONFIG_DEBUG_IRQ bool ' Debug memory allocations' CONFIG_DEBUG_SLAB bool ' Memory mapped I/O debugging' CONFIG_DEBUG_IOVIRT bool ' Magic SysRq key' CONFIG_MAGIC_SYSRQ diff -urP -I \$Id:.*Exp \$ -X /usr/src/patch.exclude linux-2.5.27-ingo-H6-org/include/asm-i386/system.h linux/include/asm-i386/system.h --- linux-2.5.27-ingo-H6-org/include/asm-i386/system.h Wed Jul 24 12:50:03 2002 +++ linux/include/asm-i386/system.h Wed Jul 24 12:36:08 2002 @@ -312,9 +312,26 @@ /* interrupt control.. */ #define local_save_flags(x) __asm__ __volatile__("pushfl ; popl %0":"=g" (x): /* no input */) -#define local_irq_restore(x) __asm__ __volatile__("pushl %0 ; popfl": /* no output */ :"g" (x):"memory", "cc") +#define _local_irq_restore(x) __asm__ __volatile__("pushl %0 ; popfl": /* no output */ :"g" (x):"memory", "cc") #define local_irq_disable() __asm__ __volatile__("cli": : :"memory") -#define local_irq_enable() __asm__ __volatile__("sti": : :"memory") +#define _local_irq_enable() __asm__ __volatile__("sti": : :"memory") +#ifdef CONFIG_DEBUG_IRQ +#define test_preempt() if (unlikely(! current_thread_info()->preempt_count)){ \ + printk("bad: irq_restore() with preemption_enabled!\n");\ + show_stack(NULL); } +#else +#define test_preempt() +#endif +#define local_irq_enable() \ + do { _local_irq_enable(); test_preempt(); } while(0) +#define local_irq_restore(x) \ + do { _local_irq_restore(x); test_preempt(); } while(0) +#define local_irq_enable_preempt() \ + do { _local_irq_enable(); preempt_check_resched() ; } while(0) +#define local_irq_restore_preempt(x) \ + do { _local_irq_restore(x); preempt_check_resched(); } while(0) + + /* used in the idle loop; sti takes one instruction cycle to complete */ #define safe_halt() __asm__ __volatile__("sti; hlt": : :"memory") diff -urP -I \$Id:.*Exp \$ -X /usr/src/patch.exclude linux-2.5.27-ingo-H6-org/include/linux/spinlock.h linux/include/linux/spinlock.h --- linux-2.5.27-ingo-H6-org/include/linux/spinlock.h Wed Jul 24 12:50:03 2002 +++ linux/include/linux/spinlock.h Wed Jul 24 12:39:39 2002 @@ -26,17 +26,17 @@ #define write_lock_irq(lock) do { local_irq_disable(); write_lock(lock); } while (0) #define write_lock_bh(lock) do { local_bh_disable(); write_lock(lock); } while (0) -#define spin_unlock_irqrestore(lock, flags) do { _raw_spin_unlock(lock); local_irq_restore(flags); preempt_enable(); } while (0) +#define spin_unlock_irqrestore(lock, flags) do { _raw_spin_unlock(lock); local_irq_restore_preempt(flags); } while (0) #define _raw_spin_unlock_irqrestore(lock, flags) do { _raw_spin_unlock(lock); local_irq_restore(flags); } while (0) -#define spin_unlock_irq(lock) do { _raw_spin_unlock(lock); local_irq_enable(); preempt_enable(); } while (0) +#define spin_unlock_irq(lock) do { _raw_spin_unlock(lock); local_irq_enable_preempt(); } while (0) #define spin_unlock_bh(lock) do { spin_unlock(lock); local_bh_enable(); } while (0) -#define read_unlock_irqrestore(lock, flags) do { _raw_read_unlock(lock); local_irq_restore(flags); preempt_enable(); } while (0) -#define read_unlock_irq(lock) do { _raw_read_unlock(lock); local_irq_enable(); preempt_enable(); } while (0) +#define read_unlock_irqrestore(lock, flags) do { _raw_read_unlock(lock); local_irq_restore_preempt(flags); } while (0) +#define read_unlock_irq(lock) do { _raw_read_unlock(lock); local_irq_enable_preempt(); } while (0) #define read_unlock_bh(lock) do { read_unlock(lock); local_bh_enable(); } while (0) -#define write_unlock_irqrestore(lock, flags) do { _raw_write_unlock(lock); local_irq_restore(flags); preempt_enable(); } while (0) -#define write_unlock_irq(lock) do { _raw_write_unlock(lock); local_irq_enable(); preempt_enable(); } while (0) +#define write_unlock_irqrestore(lock, flags) do { _raw_write_unlock(lock); local_irq_restore_preempt(flags); } while (0) +#define write_unlock_irq(lock) do { _raw_write_unlock(lock); local_irq_enable_preempt(); } while (0) #define write_unlock_bh(lock) do { write_unlock(lock); local_bh_enable(); } while (0) #define spin_trylock_bh(lock) ({ int __r; local_bh_disable();\ __r = spin_trylock(lock); \ diff -urP -I \$Id:.*Exp \$ -X /usr/src/patch.exclude linux-2.5.27-ingo-H6-org/kernel/fork.c linux/kernel/fork.c --- linux-2.5.27-ingo-H6-org/kernel/fork.c Wed Jul 24 12:50:03 2002 +++ linux/kernel/fork.c Wed Jul 24 12:46:52 2002 @@ -753,10 +753,8 @@ current->time_slice = 1; preempt_disable(); scheduler_tick(0, 0); - local_irq_restore(flags); - preempt_enable(); - } else - local_irq_restore(flags); + } + local_irq_restore_preempt(flags); /* * Ok, add it to the run-queues and make it diff -urP -I \$Id:.*Exp \$ -X /usr/src/patch.exclude linux-2.5.27-ingo-H6-org/kernel/sched.c linux/kernel/sched.c --- linux-2.5.27-ingo-H6-org/kernel/sched.c Wed Jul 24 12:50:03 2002 +++ linux/kernel/sched.c Wed Jul 24 12:12:02 2002 @@ -907,6 +907,7 @@ printk("bad: schedule() with irqs disabled!\n"); show_stack(NULL); preempt_enable_no_resched(); + return; } need_resched: diff -urP -I \$Id:.*Exp \$ -X /usr/src/patch.exclude linux-2.5.27-ingo-H6-org/mm/slab.c linux/mm/slab.c --- linux-2.5.27-ingo-H6-org/mm/slab.c Wed Jul 24 12:50:03 2002 +++ linux/mm/slab.c Wed Jul 24 12:38:27 2002 @@ -1386,9 +1386,8 @@ } else { STATS_INC_ALLOCMISS(cachep); objp = kmem_cache_alloc_batch(cachep,flags); - local_irq_restore(save_flags); /* end of non-preemptible region */ - preempt_enable(); + local_irq_restore_preempt(save_flags); if (!objp) goto alloc_new_slab_nolock; return objp;
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Tue Jul 30 2002 - 14:00:17 EST