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Date: Tue, 31 Aug 2010 07:59:35 -0700
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From: ron minnich <rminnich@gmail.com>
To: Fans of the OS Plan 9 from Bell Labs <9fans@9fans.net>
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Subject: Re: [9fans] problem with building from source on vx32 solved
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On Tue, Aug 31, 2010 at 5:54 AM, erik quanstrom <quanstro@quanstro.net> wro=
te:
>> A simple change:
>> pid =3D getpid();
>
> shouldn't you just fix it so _tos->pid is set?

yep. I just have to find the time.

>
> also, the comments in the new nsec.c don't
> match the code. =A0the code looks something like this
>
> =A0 =A0 =A0 =A0do{
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0...
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0tries =3D 0;
> =A0 =A0 =A0 =A0}while(tries++ =3D=3D 0); =A0 /* retry once */
>
> of course either this should be
>
> =A0 =A0 =A0 =A0/* just retry for ever */
> =A0 =A0 =A0 =A0for(;;){
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0...
> =A0 =A0 =A0 =A0}
> or
> =A0 =A0 =A0 =A0/* retry once */
> =A0 =A0 =A0 =A0for(tries =3D 0; tries < 2; tries++)
>
> also, there's nothing stoping the race between
> - two procs allocating the same element of the pid array
> - two procs opening the global fd twice



personal opinion: the difficulty of getting this code right, and its
complexity, tell me something is wrong with the interface. Look at the
trouble we're going through to get a 64-bit number out of the kernel.
Look at how hard it is to get right.

Two ways out:
1. "reserved" fds. an fd that is always open, can not be closed, and
will return important values, e.g. reserved fd 32766 could always be a
connection to bintime
2. a system call to get bintime.

others? Either way I don't see the current approach as making a lot of sens=
e.

ron