Hi, A couple of months ago, Pierre Peiffer has submitted a patch series to enable checkpointing / restarting ipcs. 4 of these patches were related to semaphores: https://lists.linux-foundation.org/pipermail/containers/2008-January/thread.html#9756 https://lists.linux-foundation.org/pipermail/containers/2008-January/thread.html#9757 https://lists.linux-foundation.org/pipermail/containers/2008-January/thread.html#9758 https://lists.linux-foundation.org/pipermail/containers/2008-January/thread.html#9759 They introduced a new procfs file: /proc/<pid>/semundo to read and write the semaphores undo values for a given process. These patches are widely used in the -lxc development tree cryo code is based upon. (more information about lxc can be found at http://lxc.sourceforge.net/ and the development tree can be found there too - under the patches link). Manfred Spraul, on his side, has rewritten an important part of the semaphores code. See: 1. http://lkml.org/lkml/2008/5/24/92 2. http://lkml.org/lkml/2008/5/24/93 3. http://lkml.org/lkml/2008/5/24/90 4. http://lkml.org/lkml/2008/5/24/91 Mainly patches 1 and 4 made Pierre's patches unappliable. . patch 1 changed the semundo_list proc_list field into a linked list. . patch 2 . reversed the locking order of the sem_undo_list lock and the semaphore lock. . converted the sem_undo structure to use rcu. Since 2.6.26-rc5-mm3 is now the new target for the -lxc development tree, I've ported them and taking this opportunity to resubmit them to the containers list. I have in mind a simpler solution, which I think I'll propose next week: instead of writing into the /proc/<pid>/semundo of a third party process, only allow the write operation to be done for <current>. Kathy, can you please pull in these patches? Regards, Nadia -- _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers
