Re: 2.1.93 uniprocessor with SMP kernel -- partial success

Linus Torvalds (torvalds@transmeta.com)
Wed, 8 Apr 1998 14:58:04 -0700 (PDT)


On Wed, 8 Apr 1998, Adam J. Richter wrote:
>
> Thanks for the pointer, Linus. I can confirm that turning off
> CONFIG_SERIAL_ECHO per your advice did indeed solve the "2400 baud
> console" problem.

Good.

> I can also confirm that my system still locks up hard
> under 2.1.93 after a few minutes of running X windows even if
> I buld 2.1.93 without SMP. In a sense, this is good news, because
> it means that I do not see any *SMP-related* functional problems.

There's a new problem with the code that tried to solve the SMP io-request
spinlock problems. In particular, "unplug_device()" used to call in to the
device driver with interrupts disabled, the new version has moved it to
outside the interrupt disabled region. That might result in some nasty
re-entrancy issues.

Ingo, would you think about this? I agree with your change wrt the
io_request_lock, but it definitely looks a bit fishy wrt this.

Linus

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