Re: [patch] cache color info for remote X sessions [Was: Emacs 21/X11 generating unbelieveable network traffic]

[Richard Stallman]

    Another obvious thing to cache would be the font data that emacs can
    request, although it is much less clear to me how to cache the XExtData
    list that is potentially contained in an XFontStruct (namely, how do you
    know how big the private data is?  If anyone has any suggestions here, I'd
    like to hear them).

Maybe the thing to do is to copy and cache just the data that Emacs
actually looks at in that code.

For fonts that are actually being used for display, Emacs already has
a cache.  So I suspect (though I'm partly guessing) that this is for
some other part of Emacs which is just thinking about fonts and not
actually using them.  If that is true, I suspect that the parts of the
font data it uses are rather limited.