Re: Callbacks

From: Paul H. Hargrove (PHHargrove_at_lbl_dot_gov)
Date: Wed Feb 23 2005 - 10:29:47 PST

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    If *any* caller of cr_checkpoint() indicates a failure 
    (CR_CHECKPOINT_TEMP_FAILURE or CR_CHECKPOINT_PERM_FAILURE) then no 
    checkpoint will be taken.  The assumption is that each callback is 
    managing some important resource that the process will not be able to 
    restart without.  Thus we assume that they must all succeed or the 
    checkpoint is unusable.
    
    In the TEMP case, the process is returned to a running state.  In the 
    PERM case the process is aborted.
    
    -Paul
    
    Michael Klemm wrote:
    
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    > Hi,
    >
    > Paul H. Hargrove wrote:
    > | Micheal,
    > |   Ulisses is correct, our design uses a single callback for
    > | "checkpoint", "continue after taking checkpoint" and "restart from
    > | checkpoint".  The later two cases are to be distiguished by the value
    > | returned from cr_checkpoint().
    >
    > Ah... OK. After re-reading the headers and getting an example to work I
    > understand that fact.  Afterall, I can assume that each callback routine
    > has to call cr_checkpoint to allow BLCR to proceed to the next phase
    > during checkpoint. If just one callback denies, the whole process is
    > terminated. Right?
    >
    >     -michael
    >
    > - --
    > Computer Science Department 2, University of Erlangen-Nuremberg
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    -- 
    Paul H. Hargrove                          PHHargrove_at_lbl_dot_gov
    Future Technologies Group                 
    HPC Research Department                   Tel: +1-510-495-2352
    Lawrence Berkeley National Laboratory     Fax: +1-510-486-6900
    

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