Re: qemu-kvm.git now live
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Jan Kiszka wrote:
If migration disables dirty memory logging, it must keep the vga logging enabled, and vice versa.So we need some notifier callbacks on slot changes so that all users canre-enable dirty logging after the update as required.
Simpler to do reference counting. When a user enables logging for a memory range, the refcount for all slots containing that range gets bumped. When a user enables logging for all of memory, a global refcount is bumped. For a given slot, dirty logging is enabled if either the slot logging refcount or the global logging refcount is nonzero.
That's sort of what's implemented in qemu-kvm.git. In qemu.git vga logging does not get disabled, which is really broken. It prevents optimizations like disabling logging when the screen is not displayed to a human.
Where/how does the migration code disable dirty logging?
Should be phase 3 of ram_save_live(). -- I have a truly marvellous patch that fixes the bug which this signature is too narrow to contain. -- To unsubscribe from this list: send the line "unsubscribe kvm-ia64" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html