Messages in this thread | | | Date | Fri, 29 Aug 2008 10:29:40 -0400 (EDT) | From | Steven Rostedt <> | Subject | Re: [PATCH RFC] pm_qos_requirement might sleep |
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On Fri, 29 Aug 2008, John Kacur wrote: > > Hi Andrew > > The purpose of the patch is to remove the spin_lock around the read in > the function pm_qos_requirement - since spinlocks can sleep in -rt and > this function is called from idle. I did propose a patch, that simply > removed the spinlock, since Peter Zilstra and others (yourself) point > out, the lock isn't needed to read a single word from memory. Although > the patch worked fine, Arjan objected to it, because it was not > symmetric. A reader of the code might wonder why it was locked in > other functions but not here. He suggested changing it to an atomic > type might be less confusing. The alternative which I like better > actually is to simply remove the lock in pm_qos_requirement and add a > comment for readers of the code.
This is a much better changelog, and is what should have been written in the first place ;-)
-- Steve
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