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Keir Fraser
fd6c8de67e
than discard characters in the console daemon buffers. New option: -o, --overflow-data=discard|keep This option changes the behaviour when dealing with data that overflow the max capacity of the buffer. If overflow-data is set to discard (the default), the current behaviour is used: we discard some data in the middle of the buffer. If overflow-data is set to keep, we stop listening to the ring until we free some space in the buffer. This can cause the ring to fill up and the guest kernel internal buffer to fill up as well. When this happens the guest kernel stops reading characters from the console device so the application generating data hangs. When xenconsoled resumes reading from the ring, the guest kernel will be able to resume reading from the console device as well. At that point the guest application will be allowed to continue. The risk of making this behaviour the default is that existing kernel drivers may assume they can rely on timely ring updates by the console daemon and thus themselves block on the ring being emptied. Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>