Re: [patch] Real-Time Preemption, -RT-2.6.12-rc6-V0.7.47-29

[Daniel Walker]

On Tue, 2005-06-07 at 21:41 +0200, Ingo Molnar wrote:
> ere are more microoptimizations to the spin_lock/unlock hotpath:
> 
>  - the caching of mutex_getprio() priority in p->normal_prio
> 
>  - the mutex lock/unlock paths are now all fall-through. (Found a gcc
>    bug, it mishandles __builtin_expect() in certain cases and produces 
>    correct but suboptimal code - we are working it around now.)
> 
>  - reduced the amount of recursive preemption-counter bumps via the use 
>    of raw spinlocks
> 
>  - rely on the preemption-counter instead of IRQs-off sections

There is a local_irq_enable missing someplace in UP ..

BUG: scheduling with irqs disabled: khelper/0x00000000/5
caller is __down_mutex+0x276/0x440
 [<c03a88d6>] __down_mutex+0x276/0x440 (4)
 [<c03a75cc>] schedule+0xec/0x100 (4)
 [<c03a88d6>] __down_mutex+0x276/0x440 (12)
 [<c012b290>] remove_wait_queue+0x10/0x40 (64)
 [<c0130e02>] __spin_lock+0x22/0x40 (32)
 [<c012b290>] remove_wait_queue+0x10/0x40 (8)
 [<c0130e8c>] _spin_lock_irqsave+0xc/0x20 (12)
 [<c012b290>] remove_wait_queue+0x10/0x40 (8)
 [<c012b290>] remove_wait_queue+0x10/0x40 (4)
 [<c0126a2b>] worker_thread+0x14b/0x280 (20)
 [<c01265a0>] __call_usermodehelper+0x0/0x60 (16)
 [<c0112d20>] default_wake_function+0x0/0x40 (28)
 [<c0112d20>] default_wake_function+0x0/0x40 (32)
 [<c01268e0>] worker_thread+0x0/0x280 (36)
 [<c012af24>] kthread+0x84/0xc0 (4)
 [<c012aea0>] kthread+0x0/0xc0 (20)
 [<c010132d>] kernel_thread_helper+0x5/0x18 (16)




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