From: Paul Mackerras <paulus@samba.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Huang Ying <ying.huang@intel.com>, Ingo Molnar <mingo@elte.hu>,
"H. Peter Anvin" <hpa@zytor.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Andi Kleen <andi@firstfloor.org>, dhowells <dhowells@redhat.com>,
Russell King <rmk@arm.linux.org.uk>,
Kyle McMartin <kyle@mcmartin.ca>,
Martin Schwidefsky <schwidefsky@de.ibm.com>,
davem <davem@davemloft.net>,
Linux-Arch <linux-arch@vger.kernel.org>
Subject: Re: [PATCH -tip -v5] irq_work: generic hard-irq context callbacks
Date: Mon, 20 Sep 2010 14:20:11 +1000 [thread overview]
Message-ID: <20100920042011.GA13542@drongo> (raw)
In-Reply-To: <1284728802.28028.470.camel@twins>
On Fri, Sep 17, 2010 at 03:06:42PM +0200, Peter Zijlstra wrote:
> Provide a mechanism that allows running code in IRQ context. It is most
> useful for NMI code that needs to interact with the rest of the system
> -- like wakeup a task to drain buffers.
>
> Perf currently has such a mechanism, so extract that and provide it as a
> generic feature, independent of perf so that others may also benefit.
>
> The IRQ context callback is generated through self-IPIs where possible,
> or on architectures like powerpc which have soft-disabled IRQs, its ran
> on the soft-enable path.
Actually these days we do it by setting the decrementer (the built-in
timer facility) to generate an interrupt immediately (well, within one
timebase tick, i.e. a small number of nanoseconds).
Paul.
next prev parent reply other threads:[~2010-09-20 4:49 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-17 2:05 [PATCH -tip -v5] irq_work: generic hard-irq context callbacks Huang Ying
2010-09-17 13:06 ` Peter Zijlstra
2010-09-20 4:20 ` Paul Mackerras [this message]
2010-09-20 9:13 ` Peter Zijlstra
2010-09-21 3:05 ` Paul Mackerras
2010-09-21 18:20 ` Peter Zijlstra
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