Messages in this thread | | | Date | Wed, 10 Nov 1999 22:42:04 +0100 | From | Marcel Lanz <> | Subject | Re: [question/comment/help] pseudo function-call from kernel to a user-process |
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Pavel Machek wrote: snip snap > > OK. This works. My Questions: > > - can I do this in an other way ? Is there any functionality in the > > kernel to do somethin like this? > > - as you can see int the code, I tried to use a self-defined spinlock to > > protect the area, but that doesn't work, why? aren't spinlocks like > > semaphores or mutex'es? > > Spinlocks are NOP on uniprocessor. > > > - are there any pitfalls ? > > Yes. Think hard about deadlocks. thank you, I have to think harder on it. I saw that I havent to use a spinlock really, or a semaphore to protect somthing. All info is task-local. (spinlocks perhaps become more serious if I want to run it on SMP-maschines)
> Well - when I was about to do something like this (block device in > userland), I called it network block device. Loopback network is quite > nice to use. > > > void on_sigusr2(int signal) > > { > > char* node_name; > > char* buff; > > > > node_name = (char*) malloc(64); > > buff = (char*) malloc(64); > > > > printf("sigusr2 from kernel reveived\n"); > > dkmctl(DKM_MAP_REQ, buff, NULL); > > printf("buff is: %s\n", buff); > > strcpy(node_name, "orinoco"); > > What's that? Some kind of distributed system? I WANT THAT! Yes. It's my diploma-work. dkm is "distributed kernel multiprocessing". I'll send you a email, if it runs ;)
> I have two machines, and would like to use them both for kernel > compiles. Bitcluster has some serious problems :-( and mj's slice is > 2.2. only and I was unable to port it. Yes, dkm should/will do that transparently.
greetings marcel -- Marcel Lanz <marcel.lanz@ds9.ch>
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