Messages in this thread | | | Date | Tue, 11 Sep 2012 17:03:48 +0200 | From | Manfred Spraul <> | Subject | Re: [PATCH v4 8/9] IPC: message queue copy feature introduced |
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On 08/13/2012 02:32 PM, Stanislav Kinsbursky wrote: > This patch is required for checkpoint/restore in userspace. > IOW, c/r requires some way to get all pending IPC messages without deleting > them from the queue (checkpoint can fail and in this case tasks will be resumed, > so queue have to be valid). > To achive this, new operation flag MSG_COPY for sys_msgrcv() system call was > introduced. If this flag was specified, then mtype is interpreted as number of > the message to copy. > If MSG_COPY is set, then kernel will allocate dummy message with passed size, > and then use new copy_msg() helper function to copy desired message (instead of > unlinking it from the queue). > > Notes: > 1) Return -ENOSYS if MSG_COPY is specified, but CONFIG_CHECKPOINT_RESTORE is > not set. How is CONFIG_CHECKPOINT_RESTORE set? I'm not sure, but I think it should be added to Kconfig.
-- Manfred
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