From: "Chen, Kenneth W" <kenneth.w.chen@intel.com>
To: linux-ia64@vger.kernel.org
Subject: RE: PMU and timer interrupts
Date: Mon, 13 Feb 2006 22:49:57 +0000 [thread overview]
Message-ID: <200602132249.k1DMnvg15069@unix-os.sc.intel.com> (raw)
In-Reply-To: <20060209171648.GA26865@frankl.hpl.hp.com>
Chen, Kenneth W wrote on Monday, February 13, 2006 12:32 PM
> Stephane Eranian wrote on Monday, February 13, 2006 12:13 PM
> > Jes seems to believe than this is more historical than anything for qla2xxx.
> > Now what about the timer interrupt, why does it really need SA_INTERRUPT especially
> > given that it is so high priority and with the TPR mechanism. IT seems to be
> > a protection against MCA, IPI, IPI_RESCHEDULE based on the current layout.
>
> scheduler_tick function expects irq off because it calls load_balance and
> will muck around with runqueue list. Won't that race with resched IPI if
> irq is not masked?
NO! Ken needs more coffee Monday morning ....
I forgot that we don't check TIF_ flag when we are still on kernel stack.
So resched IPI should be safe w.r.t timer interrupt because schedule is
called after timer_interrupt finishes.
- Ken
next prev parent reply other threads:[~2006-02-13 22:49 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-02-09 17:16 PMU and timer interrupts Stephane Eranian
2006-02-09 18:16 ` Jack Steiner
2006-02-09 18:20 ` Luck, Tony
2006-02-09 18:39 ` Stephane Eranian
2006-02-09 19:10 ` Jack Steiner
2006-02-09 19:11 ` Stephane Eranian
2006-02-10 13:35 ` Stephane Eranian
2006-02-10 13:54 ` Jes Sorensen
2006-02-10 20:33 ` Chen, Kenneth W
2006-02-10 21:22 ` Stephane Eranian
2006-02-10 23:04 ` Chen, Kenneth W
2006-02-10 23:21 ` Stephane Eranian
2006-02-10 23:26 ` Jes Sorensen
2006-02-13 10:38 ` Stephane Eranian
2006-02-13 10:53 ` Jes Sorensen
2006-02-13 20:01 ` Stephane Eranian
2006-02-13 20:12 ` Stephane Eranian
2006-02-13 20:13 ` Chen, Kenneth W
2006-02-13 20:32 ` Chen, Kenneth W
2006-02-13 21:26 ` Keith Owens
2006-02-13 22:49 ` Chen, Kenneth W [this message]
2006-02-13 23:46 ` Stephane Eranian
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