Date: Tue, 24 Oct 1995 21:34:47 -0700 (PDT) From: Julian Elischer <julian@ref.tfs.com> To: terry@lambert.org (Terry Lambert) Cc: bugs@ns1.win.net, hackers@FreeBSD.ORG Subject: Re: process migration Message-ID: <199510250434.VAA16988@ref.tfs.com> In-Reply-To: <199510250359.UAA18032@phaeton.artisoft.com> from "Terry Lambert" at Oct 24, 95 08:59:29 pm
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> > > There's also other problems: > > 1) File as swap store. The executable file is acting as its own > swap store; this means you must reopen the file (which means > you need its name) and reestablish the flags on the vnode to > orevent writes to it. write the entire process space including non resident pages.. (implies that shared programs become static ) > > 2) Memory overcommit. There very well may not be enough swap > to checkpoint the program. put it out to a file....... > > 3) Shared libraries. The shared library mappings must be > restored, probably seperately. static.. quite possibly this might be used in a specialist environment (such as what russel is working on,) where shared libs might not be required in any case) > > 4) Shared memory, semaphores, etc. this gets hard, > > 5) Open file descriptors. you can only do a single process, file descriptors not open to files probably are pointed deadfs (as if the other end died) > > 6) Network listens (recoverable) and network connections (not > recoverable if reliable stream delivery, recoverable for > stateless datagrams). listens can probably be re-established if you can track them down.. certainly a certain amount of info can be stored on each fd, and a listen sounds feasible to restart.. > > 7) Mapped files (other than shared libraries). > > 8) FIFO/pipe/cooperating process recovery. > > This is a non-trivial task. I guess that's whey they decided to do it :) > > > > Terry Lambert > terry@lambert.org > --- > Any opinions in this posting are my own and not those of my present > or previous employers. >
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