From: "Jan Beulich" <jbeulich@novell.com>
To: Juergen Gross <juergen.gross@fujitsu-siemens.com>
Cc: "xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>
Subject: Re: [Patch] don't spin with irq disabled
Date: Thu, 26 Mar 2009 12:23:14 +0000 [thread overview]
Message-ID: <49CB81C2.76E4.0078.0@novell.com> (raw)
In-Reply-To: <49CB441E.9030006@fujitsu-siemens.com>
>>> Juergen Gross <juergen.gross@fujitsu-siemens.com> 26.03.09 10:00 >>>
>Attached patch reduces interrupt latency in lock handling.
>spin_lock_irq and spin_lock_irqsave used to turn off IRQs and then tried to
>get the lock. If the lock was already held, waiting for the lock was done with
>IRQs still off.
>The patch reenables IRQs during the wait loop.
This is wrong - you must not enable interrupts if they weren't enabled upon
entry to these two functions.
Jan
next prev parent reply other threads:[~2009-03-26 12:23 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-03-26 9:00 [Patch] don't spin with irq disabled Juergen Gross
2009-03-26 12:23 ` Jan Beulich [this message]
2009-03-26 12:36 ` Juergen Gross
2009-03-27 7:41 ` Jan Beulich
2009-03-27 9:09 ` Keir Fraser
2009-03-27 17:00 ` spinlock requests (was RE: [Patch] don't spin with irq disabled) Dan Magenheimer
2009-03-27 17:46 ` Keir Fraser
2009-03-27 18:00 ` Dan Magenheimer
2009-03-27 18:12 ` Keir Fraser
2009-04-02 23:08 ` Dan Magenheimer
2009-04-03 7:17 ` Keir Fraser
2009-03-30 6:11 ` Juergen Gross
2009-03-31 13:12 ` Dan Magenheimer
2009-03-31 13:40 ` Juergen Gross
2009-03-31 13:48 ` Keir Fraser
2009-03-31 19:00 ` Jeremy Fitzhardinge
2009-03-31 20:57 ` Keir Fraser
2009-03-31 21:16 ` Jeremy Fitzhardinge
2009-03-26 14:27 ` [Patch] don't spin with irq disabled Keir Fraser
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