Messages in this thread | | | Date | Tue, 24 Feb 2015 17:55:40 +0100 | From | Sebastian Andrzej Siewior <> | Subject | Re: [RFC PATCH] futex: Remove requirement for lock_page in get_futex_key |
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On 2014-02-11 16:51:55 [+0100], Thomas Gleixner wrote: > On Wed, 30 Oct 2013, Mel Gorman wrote: > > On Wed, Oct 30, 2013 at 09:45:31AM +0100, Thomas Gleixner wrote: > > > On Tue, 29 Oct 2013, Mel Gorman wrote: > > > > Patch boots and futextest did not explode but I did no comparison > > > > performance tests. Thomas, do you have details of the workload that > > > > drove you to examine this problem? Alternatively, can you test it and > > > The scenario is simple. All you need is a PSHARED futex. > > > > > > Task A > > > get_futex_key() > > > lock_page() > > > > > > ---> preemption > > > > > Do please. I'd rather not sink time into trying to reproduce a hypothetical > > problem when people who are already familiar with it can provide better > Took some time, but the folks finally came around to give it a try and > it fixes their problem. I did not explode either, but I doubt, that > their workload can trigger any of the corner cases.
I just stumbled uppon this patch and now I am curious about its status. tglx said that it solves the problem in question (with doubt of triggering all the corner cases). Chris pointed out that moving put_page() might be worth doing.
Sebastian
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