From: "Ken Chen" <kenchen@google.com>
To: linux-ia64@vger.kernel.org
Subject: Re: [PATCH] disable irq's and check need_resched before safe_halt
Date: Tue, 07 Aug 2007 21:26:16 +0000 [thread overview]
Message-ID: <b040c32a0708071426g3b42dc84oa2209a64c3dc33d3@mail.gmail.com> (raw)
In-Reply-To: <20070807134932.GA30447@sgi.com>
On 8/7/07, Luck, Tony <tony.luck@intel.com> wrote:
> This looks like it re-introduces code that Ken Chen backed out
> about two years ago. Here's Ken's commit that explains what
> broke last time we made the idle loop look like this. Now
> that code was wider ranging ... messing with TIF bits too,
> so maybe this is different this time?
Yeah, I think the TIF flag was the key in fixing the resched IPI
notification. The change in default_idle() is an optimization.
I'm horrified to see the same code coming back: doing interrupt
enable/disable in the most inner while loop. Disable interrupt is
just crude, but I suppose that's the only way to resolve the race
condition? Looking at other arch like x86_64, it is also doing the
same thing.
- Ken
next prev parent reply other threads:[~2007-08-07 21:26 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-08-07 13:49 [PATCH] disable irq's and check need_resched before safe_halt Dimitri Sivanich
2007-08-07 20:11 ` Luck, Tony
2007-08-07 21:26 ` Ken Chen [this message]
2007-08-08 15:01 ` Dimitri Sivanich
2007-08-09 3:36 ` Hidetoshi Seto
2007-08-09 12:41 ` Dimitri Sivanich
2007-08-13 20:36 ` Luck, Tony
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