Messages in this thread | | | Date | Tue, 4 Oct 2011 15:46:53 +0200 | From | Borislav Petkov <> | Subject | Re: [BUGFIX][PATCH] Freezer, CPU hotplug, x86 Microcode: Fix task freezing failures |
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On Tue, Oct 04, 2011 at 06:45:12PM +0530, Srivatsa S. Bhat wrote: > I would like to propose a modified solution to the problem: > > Taking a CPU offline: > * Upon a CPU_DEAD notification, just like the code originally did, we free > the kernel's copy of the microcode and invalidate it. So no changes here. > > Bringing a CPU online: > * When a CPU_ONLINE or CPU_ONLINE_FROZEN notification is received, > a. If the userspace is not frozen, we request microcode from userspace and > apply it to the cpu. > > b. However if we find that the userspace is frozen at that moment, we defer > applying microcode now and register a callback function to be executed > immediately when the userspace gets thawed. This callback function would > request microcode from userspace and apply it to the cpu.
No need for that if we can drop the whole re-requesting of ucode on CPU_ONLINE* (see my other mail). Let me run some tests before though.
Thanks.
-- Regards/Gruss, Boris.
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