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From: GKN%OAK.SAINET.MFENET@LLL-MFE.ARPA
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Subject: EXE$DEANONPAGED and EXE$ALONONPAGED
Message-ID: <8602020146.AA25596@ucbvax.berkeley.edu>
Date: Thu, 30-Jan-86 19:12:00 EST
Article-I.D.: ucbvax.8602020146.AA25596
Posted: Thu Jan 30 19:12:00 1986
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Date:    Thu, 30-JAN-1986 19:14 EST
To:      info-vax@sri-kl.arpa
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        From:   Arpa%"dean  @A.PSY.CMU.EDU" 29-JAN-1986 06:06
        Subj:   EXE$ALONONPAGED and EXE$DEANONPAGED
        Date:   Monday, 27 Jan 86 15:09:25 EST

        The problem I suspect is a synch probelm with allocation and
        dealloction of memory.  ie. I am in the middle of a dealloction, the
        system interrupts at high IPL and is able to allocate the peice I
        just deaalocated.  I then finish deallocating.  When the kernel mode
        ast later dealloctes a previously deallocted piece, POW.
        The Fiche doesn't mention any need to raise IPL when allocating or
        deallocting though.

        Anyone have any thoughts/experience/comments ?

        Randall W. Dean

Well, the only thing I can think of is that you ALWAYS RAISE IPL to
synchronize access, never lower it.  For EXE$ALONONPAGED, this means
that your current IPL must be .leq. IPL$_MAILBOX (11) when you call
it.  If you are at a higher IPL (eg - device interrupt level), then
you must create a fork process at a lower IPL in order for it to raise
IPL to allocate memory.

Regards,

gerard

[sorry if you get the top half of this - my fingers slipped]