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at Oct 12, 2012 at 8:27 pm
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On 2012/10/12 18:35:23, rsc wrote:
I'm sorry, but we're not going to use bitfields here. They have a long history
of problems and complications, and I'd prefer that we keep them out of this code
base.
The bitfields were part of CL 6345044. I will delete them from 6345044.
I have no problem collapsing the fields into a uint64 flag or
something like
that, which can be tested with if(n->flag & Whatever) etc.
I'm a little surprised that these 6 bytes are the main memory
overhead.
It is true that there exist larger memory overheads.
Removing
even a single pointer field, such as by making Val val into Val *val, allocated
as needed, seems like it would have a larger effect.
sizeof(Val) is just 2 pointers, so the effect of replacing it with Val*
is of the same order as the effect of collapsing the 6 bytes in this CL.
The code in src/cmd/gc/walk.c seems incorrect (uchar may overflow?), so
at the very least we could merge src/cmd/gc/walk.c
I think there's interesting work to be done here but I would prefer it to be
driven by profiling data.
https://codereview.appspot.com/6650054/
