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From: Oleg Nesterov <oleg@tv-sign.ru>
To: linux-kernel@vger.kernel.org
Cc: Ingo Molnar <mingo@elte.hu>
Subject: Re: [announce, patch, RFC] "big IRQ lock" removal, IRQ cleanups.
Date: Sat, 20 Jul 2002 21:57:32 +0400	[thread overview]
Message-ID: <3D39A48C.C0863416@tv-sign.ru> (raw)

Hello.

> - to remove the preemption count increase/decrease code from the lowlevel
>   IRQ assembly code.

So do_IRQ() can start with preempt_count == 0.
Suppose another cpu sets TIF_NEED_RESCHED flag
at the same time.

spin_lock(&desc->lock) sets preempt_count == 1.
Before calling handle_IRQ_event() (which adds IRQ_OFFSET
to preempt_count), do_IRQ() does spin_unlock(&desc->lock)
and falls into schedule().

Am I missed something?

It seems to me that call to irq_enter() must be shifted
from handle_IRQ_event() to do_IRQ().

Oleg.

             reply	other threads:[~2002-07-20 17:51 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-07-20 17:57 Oleg Nesterov [this message]
2002-07-21 23:43 ` [announce, patch, RFC] "big IRQ lock" removal, IRQ cleanups george anzinger
2002-07-21 23:50   ` Ingo Molnar
  -- strict thread matches above, loose matches on Subject: below --
2002-07-20 20:54 Ingo Molnar
2002-07-19 21:49 ` george anzinger
2002-07-20 14:25 ` Marcin Dalecki
2002-07-21 21:17   ` Ingo Molnar
2002-07-20 20:57 ` Ingo Molnar
2002-07-22 14:45 Oleg Nesterov
2002-07-22 18:03 ` george anzinger
2002-07-22 18:04   ` Ingo Molnar

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