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All data in a write buffer can be divided on two parts sent but not yet acknowledged data and unsent data. Currently the boundary between sent and unsent data is not dumped and all the data are restored as if they have already been sent. This methode can provoke long delays in tcp connection, because a kernel can wait before retransmitting data. https://bugzilla.openvz.org/show_bug.cgi?id=2808 The TCP stack must know which data have been sent, because acknowledgment can be received for them. These data must be restored in repair mode. The second part of data have never been sent out, so they can be restored without any tricks. These data can be sent into socket as usual. For restoring unsent data the repair mode is disabled for socket, but it is enabled back after restoring data. It will be disabled after unlocking network. In this case window probe is sent, which is required for waknge the connection. This patch fixes long delays in tcp connections after dumping and restoring. Thanks Pavel for the idea of disabling repair mode for restoring unsent data. https://bugzilla.openvz.org/show_bug.cgi?id=2808 Signed-off-by: Andrey Vagin <avagin@openvz.org> Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
criu ==== An utility to checkpoint/restore tasks. Some code snippets are borrowed from - Linux kernel (http://kernel.org/) - git (http://git-scm.com/) - kvm-tools (https://github.com/penberg/linux-kvm) - ptrace-parasite (https://code.google.com/p/ptrace-parasite/) Many thanks to these projects. Licensed under GPLv2 (http://www.gnu.org/licenses/gpl-2.0.txt)