Date: Wed, 30 Jun 1999 13:58:03 -0400 (EDT) From: "Brian F. Feldman" <green@unixhelp.org> To: Julian Elischer <julian@whistle.com> Cc: Garrett Wollman <wollman@khavrinen.lcs.mit.edu>, Peter Wemm <peter@FreeBSD.org>, cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/kern init_main.c kern_fork.c kern_linker.c vfs_aio.c src/sys/sys proc.h Message-ID: <Pine.BSF.4.10.9906301357250.50480-100000@janus.syracuse.net> In-Reply-To: <Pine.BSF.3.95.990630104113.12786A-100000@current1.whistle.com>
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On Wed, 30 Jun 1999, Julian Elischer wrote:
>
>
> On Wed, 30 Jun 1999, Garrett Wollman wrote:
>
> > <<On Wed, 30 Jun 1999 08:33:43 -0700 (PDT), Peter Wemm <peter@FreeBSD.org> said:
> >
> > > syscalls set p->p_retval[] themselves. Simplify the SYSINIT_KT() code
> > > and other kernel thread creators to not need to use pfind() to find the
> > > child based on the pid. While here, partly tidy up some of the fork1()
> >
> > On an almost-unrelated tangent...
> >
> > Because proc structures are now stored in type-stable memory (via the
> > zone allocator), other places in the kernel which now reference
> > processes by pid and pfind should be able to keep a reference to the
> > proc instead. (There does need to be a version number which gets
> > incremented when proc structs are recycled, but this should still be
> > cheaper than pfind().) This would benefit network applications
> > written around a poll or select loop, since the simple case of
> > selwakeup() uses pfind() to locate the specific process to wake up.
>
> Bill Jolitz added the PID stuff because there can be races where
> the proc structure is re-used..
> I can't remember the exact case but my gut feeling is that whatever it was
> is still there..
I thought about this a LOT, and it's not a great idea to hold a pointer to
the proc...
>
> julian
>
>
>
> >
> > -GAWollman
> >
> > --
> > Garrett A. Wollman | O Siem / We are all family / O Siem / We're all the same
> > wollman@lcs.mit.edu | O Siem / The fires of freedom
> > Opinions not those of| Dance in the burning flame
> > MIT, LCS, CRS, or NSA| - Susan Aglukark and Chad Irschick
> >
> >
>
>
>
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