On Wed, Aug 24 2005, Esben Nielsen wrote: > On Wed, 24 Aug 2005, Jens Axboe wrote: > > > On Wed, Aug 24 2005, Lee Revell wrote: > > > Just found this in dmesg. > > > > > > BUG: scheduling with irqs disabled: libc6.postinst/0x20000000/13229 > > > caller is ___down_mutex+0xe9/0x1a0 > > > [<c029c1f9>] schedule+0x59/0xf0 (8) > > > [<c029ced9>] ___down_mutex+0xe9/0x1a0 (28) > > > [<c0221832>] cfq_exit_single_io_context+0x22/0xa0 (84) > > > [<c02218ea>] cfq_exit_io_context+0x3a/0x50 (16) > > > [<c021db84>] exit_io_context+0x64/0x70 (16) > > > [<c011efda>] do_exit+0x5a/0x3e0 (20) > > > [<c011f3ca>] do_group_exit+0x2a/0xb0 (24) > > > [<c0103039>] syscall_call+0x7/0xb (20) > > > > Hmm, Ingo I seem to remember you saying that the following construct: > > > > local_irq_save(flags); > > spin_lock(lock); > > > > which is equivelant to spin_lock_irqsave() in mainline being illegal in > > -RT, is that correct? > > I can easily answer this for Ingo. > > Yes, spin_lock(lock) is blocking since lock is mutex, not a spinlock under > preempt-rt. But isn't it easy to fix? Replace the two lines by > spin_lock_irqsave(flags). That would work for both preempt-rt > and !preempt-rt.
Well, it might and it might not be. There's a correctness and optimization side to it. For this case it is probably doable, but I have to say that the new semantics defy normal logic. > You supposed to ask if the macro name spin_lock() isn't confusing. It very > much is, but one of Ingo's aims is not to change existing code too much. > The purist would probably change all instances of spin_lock() to lock() or > down() to stop refering to a specific lock type when it can be changed > with config-options. That would, however, require a large patch, > which does the preempt-rt branch harder to merge with the main-line. I can certainly understand Ingo's point of view, as long as he is maintaining the patch outside of the kernel. Where it ever to go in, this would have to change. -- Jens Axboe - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
