Messages in this thread | | | Subject | Re: PFs on pages pinned with get_user_pages() | From | Peter Zijlstra <> | Date | Thu, 29 Jan 2009 17:11:23 +0100 |
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On Thu, 2009-01-29 at 17:03 +0100, Frank Mehnert wrote: > On Thursday 29 January 2009, Peter Zijlstra wrote: > > > > That aside, is there any reason you have to avoid scheduling? Otherwise > > > > I would just allow so and be done with it. > > > > > > The reason is that our code expects that to ensure syncing of the CPU > > > state with the saved state. I fear it is quite difficult to change > > > that... > > > > Ah, is that what KVM uses the preempt notifiers for? Could you too? > > Right, that could be an option. > > We will try to change our code which is a big effort as we try > to keep the code as unique as possible between the different > hosts we support (Linux, Solaris, Windows, Mac OS X). > > Just to be sure: There is no other option than disabling interrupts > or calling disable_preemption() to prevent scheduling?
Thing is, lock_page() and down_read() require to be able to schedule(), so there's no way around that.
So even if there was another way to disable scheduling, you'd still have the same problem.
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