Date: Sun, 21 Mar 1999 14:01:31 +0000 (GMT) From: Brian Feldman <green@unixhelp.org> To: Matthew Dillon <dillon@apollo.backplane.com> Cc: Alfred Perlstein <bright@rush.net>, "John S. Dyson" <dyson@iquest.net>, samit@usa.ltindia.com, commiters@FreeBSD.ORG, freebsd-current@FreeBSD.ORG Subject: Re: rfork() Message-ID: <Pine.BSF.4.05.9903211357250.1144-100000@zone.syracuse.net> In-Reply-To: <199903210743.XAA09505@apollo.backplane.com>
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On Sat, 20 Mar 1999, Matthew Dillon wrote: > > :> > rfork(RFMEM) doesn't easily work from C. You need to > :> > create an assembly stub. > :> > > :> > -- > :> > John | Never try to teach a pig to sing, > :> > dyson@iquest.net | it makes one look stupid > :> > jdyson@nc.com | and it irritates the pig. > :> > > :> > :> I've seen about 6 people ask about this because the manual lies about > :> what is done. I asked a while back about it, and John was kind enough > :> to dig up some code that used rfork to properly split the stack should > :> I try to dig it up? > :> > :> In the meantime, can someone commit this or suggest something? > : > :For the suggest something, you realize that with Richard's VM_STACK code it > :should be relatively trivial to make this automatic (suggestion: add > :RFSTACK flag). > : > : Brian Feldman _ __ ___ ___ ___ > : green@unixhelp.org _ __ ___ | _ ) __| \ > : http://www.freebsd.org/ _ __ ___ ____ | _ \__ \ |) | > : FreeBSD: The Power to Serve! _ __ ___ ____ _____ |___/___/___/ > > If the goal is to completely share the address space, which > RFMEM does, you can't split anything, not even the stack. It > sure would be useful if there were a standard clib call adequate > for calling rfork() and calling a function in the child w/ a new > stack. Hence the NEW flag RFSTACK. Why would this be a bad thing? This would keep the old behavior and allow much nicer new behavior. I didn't suggest changing the old behavior. This would just greatly simplify things so all of the assembly wouldn't be needed. Hmm... actually... if one were to mmap() a stack and as soon as the rfork() returned movl newstack,%esp and whatnot, wouldn't this be a pretty simple solution? > > -Matt > Matthew Dillon > <dillon@backplane.com> > > > > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-current" in the body of the message > Brian Feldman _ __ ___ ___ ___ green@unixhelp.org _ __ ___ | _ ) __| \ http://www.freebsd.org/ _ __ ___ ____ | _ \__ \ |) | FreeBSD: The Power to Serve! _ __ ___ ____ _____ |___/___/___/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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