From: Robert Love <rml@tech9.net>
To: Jeremy Hall <jhall@maoz.com>
Cc: linux-mm@kvack.org
Subject: Re: interrupt context
Date: 14 Apr 2003 14:56:50 -0400 [thread overview]
Message-ID: <1050346609.3664.55.camel@localhost> (raw)
In-Reply-To: <200304141851.h3EIpZjV015008@sith.maoz.com>
On Mon, 2003-04-14 at 14:51, Jeremy Hall wrote:
> On a UP machine, is it possible for two interrupts to occur at once? as
> in, can card a create an interrupt while card b is in interrupt context?
Yes. Normally, all interrupts are enabled (the interrupt system is on)
but the _current_ interrupt line is masked out. Thus you will never get
a recursive interrupt (A while processing A) but you may get A while
processing B.
Note if SA_INTERRUPT flag was given to request_irq() then the interrupt
is a "fast" interrupt and runs with all interrupts disabled on the local
processor.
> what about an SMP machine operating in UP mode (nosmp)
By nature of above, yes.
If you need to ensure concurrency is protected in your interrupt
handler, grab a lock and disable interrupts around the critical region.
Robert Love
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next prev parent reply other threads:[~2003-04-14 18:56 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-04-14 18:51 interrupt context Jeremy Hall
2003-04-14 18:56 ` Robert Love [this message]
2003-04-14 19:32 ` Jeremy Hall
2003-04-14 19:35 ` Robert Love
2003-04-14 21:09 ` Jeremy Hall
2003-04-14 21:18 ` Robert Love
2003-04-14 21:48 ` Jeremy Hall
2003-04-14 22:57 ` Robert Love
2003-04-15 3:44 ` Jeremy Hall
2003-04-15 4:14 ` Jeremy Hall
2003-04-15 21:40 ` Robert Love
2003-04-15 23:02 ` Jeremy Hall
2003-04-16 3:41 ` Jeremy Hall
-- strict thread matches above, loose matches on Subject: below --
2008-03-23 21:44 Interrupt context Codrin Alexandru Grajdeanu
2008-03-24 21:00 ` Christopher Li
2008-03-25 1:34 ` Octavian Purdila
2008-03-25 2:57 ` Christopher Li
2008-03-26 12:43 ` Octavian Purdila
2008-03-26 21:53 ` Christopher Li
[not found] <CA+bLfK5FPqFvU2xy7xKdV4LkAvmY6GAPFrB-4UBzn-cOunQ6Xg@mail.gmail.com>
2012-10-05 8:51 ` interrupt context Iain Fraser
2012-10-05 9:32 ` Borislav Petkov
2012-10-05 10:20 ` Iain Fraser
2012-10-05 10:34 ` Borislav Petkov
2012-10-05 13:27 ` Theodore Ts'o
2012-10-05 14:03 ` Iain Fraser
2012-10-05 18:05 ` anish kumar
2012-10-05 18:15 ` Iain Fraser
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