Changes between Version 41 and Version 42 of processus_thread


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Timestamp:
Nov 9, 2017, 11:40:15 AM (5 years ago)
Author:
alain
Comment:

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  • processus_thread

    v41 v42  
    7979
    8080A thread of parent process P, running in a cluster X,  executes the fork() system call to create a child process C on a remote cluster Y, that will  become both the owner and the reference cluster for the C process. A new process descriptor, and a new thread descriptor must be created and initialized in target cluster Y for the child process.
    81 The calling thread  can run in any cluster. If the reference cluster Z for process P is different from the calling thread cluster X, the calling thread must use a RPC to ask the reference cluster Z to do the work, because only the reference cluster Z contains a complete description of the parent process VSL and GPT.
     81The calling thread  can run in any cluster. If the target cluster Y is different from the calling thread cluster X, the calling thread must use a RPC to ask the target cluster Y to do the work, because only the target cluster Y can allocate memory for the new process and thread descriptor.
    8282
    83 Regarding the process descriptor, a new PID must be allocated in cluster Y.  The child process C inherit the vsegs registered in the parent process VSL, but the ALMOS-MKH replication policy depends on the vseg type:
     83Regarding the process descriptor, a new PID must be allocated in cluster Y.  The child process C inherit the vsegs registered in the parent process reference VSL, but the ALMOS-MKH replication policy depends on the vseg type:
    8484 * for the '''DATA, MMAP, REMOTE''' vsegs (containing shared, non replicated data), all vsegs registered in the parent reference VSL(Z,P) are registered in the child  reference VSL(Y,C), and all valid GPT entries in the reference parent GPT(Z,P) are copied in the child reference GPT(Y,C). For all pages, the WRITABLE flag is reset and the COW flag is set, in both (parent and child) GPTs. This require to update all replicated parent GPT copies in all cluster.
    8585 * for the '''STACK''' vseg(that are private), only one vseg is registered in the child reference VSL(Y,C). This vseg contains the user stack of the user thread requesting the fork, running in cluster X. All valid GPT entries in the parent GPT(X,P) are copied in the child GPT(Y,C). For all pages, the WRITABLE flag is reset and the COW flag is set, in both (parent and child) GPTs. This require to update all replicated parent GPT copies in all cluster.