dg@informix.com (David Gould) writes:
[ reversed, and possibly bad NS32K patch removed from quoted material. ]
> I wish I had noticed this before Bruce applied it.
Me too, I wrote a quick hack that worked, and I always like people
who know what's really going on to double check things when possible.
> The TAS function is needed so that stuck spinlocks can be recovered from.
> Also, it enables the pseudo random back off which helps performance when
> there are many backends.
I suspected as much, which is why I wrote a tas function to fix
the link errors, rather than try to remove the code that called
tas.
> In any case, this patch does not "follow the one true path" that I tried
> to outline in s_lock.c and s_lock.h. In fact it is exactly backwards.
>
> Basically the preferred way is:
>
> - in s_lock.h do nothing, the defaults should take care of you.
>
> -in s_lock.c define a TAS function that sets the spinlock and returns the
> previous state of the lock.
>
> I see from your asm()s that you are using gcc. In this case, your TAS function
> should be called tas(), and should be defined inside the __GNUC__ section.
Your quote removes the comment that says something to the effect
of: I think I built a bogus patch, you might need patch -r to make
it work because it's backwards. In fact you might need more than
that to get the right pathnames in the right places. (My quoting
removes the whole patch... 8-) I built the patch by hand, since
cvs patch spewed out a whole bunch of stuff in files I know I never
touched. I figured they were altered in the build process or
something...
However, what I did on my machine was to remove a #define S_LOCK ...
from s_lock.h and add function tas in s_lock.c. It wouldn't link
the way it came out of cvs checkout, but it would with the changes
I just described.
I suspect Bruce got it right, otherwise hed have a handful of
garbled code. I think it *might* be like you describe it should
be, but please double check it, I will. (Like I said above, the
more the better, since I don't really know what I'm doing, just
making some guesses.)
